len(st1):\\n\\t\\t\\t(st1, st2) = (st2, st1)\\n\\t\\t\\t(s1, s2) = (s2, s1)\\n\\t\\t\\torde = not orde\\n\\t\\trml = []\\n\\t\\tfor el in st2:\\n\\t\\t\\tif el in st1:\\n\\t\\t\\t\\trml.append(el)\\n\\t\\tfor el in rml:\\n\\t\\t\\tst1.remove(el)\\n\\t\\t\\tst2.remove(el)\\n\\t\\ttot = len(st1) + len(st2)\\n\\t\\tif tot & 1:\\n\\t\\t\\tpl = []\\n\\t\\t\\tbreak\\n\\t\\tfor k in st2:\\n\\t\\t\\tst1.add(k)\\n\\t\\t\\tpl.append((k, k))\\n\\t\\t\\t(s1[k], s2[k]) = (s2[k], s1[k])\\n\\t\\tfor j in range(tot // 2):\\n\\t\\t\\tk1 = st1.pop()\\n\\t\\t\\tk2 = st1.pop()\\n\\t\\t\\tpl.append((k1, k2) if orde else (k2, k1))\\n\\t\\t\\t(s1[k1], s2[k2]) = (s2[k2], s1[k1])\\n\\tif pl == []:\\n\\t\\tprint('No')\\n\\telse:\\n\\t\\tprint(f'Yes\\\\n{len(pl)}\\\\n' + ''.join([f'{tup[0] + 1} {tup[1] + 1}\\\\n' for tup in pl]))\\n\",\n \"t = int(input())\\nfor l in range(t):\\n\\tn = int(input())\\n\\ts = input()\\n\\tk = input()\\n\\tds = list()\\n\\tdk = list()\\n\\tfor i in range(n):\\n\\t\\tif s[i] != k[i]:\\n\\t\\t\\tds.append(s[i])\\n\\t\\t\\tdk.append(k[i])\\n\\tif len(dk) != 2:\\n\\t\\tprint('NO')\\n\\telif dk[0] == dk[1] and ds[0] == ds[1]:\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"import sys\\nip = lambda : sys.stdin.readline().rstrip()\\nfrom collections import *\\nfor _ in range(int(ip())):\\n\\tn = int(ip())\\n\\ts = ip()\\n\\tt = ip()\\n\\tct = 0\\n\\td = Counter(s)\\n\\te = Counter(t)\\n\\tfl = False\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tct += 1\\n\\t\\t\\tif ct == 1:\\n\\t\\t\\t\\tprev1 = s[i]\\n\\t\\t\\t\\tprev2 = t[i]\\n\\t\\t\\tif ct == 2:\\n\\t\\t\\t\\tif s[i] == prev1 and t[i] == prev2:\\n\\t\\t\\t\\t\\tfl = True\\n\\tif ct == 2 and fl or ct == 0:\\n\\t\\tprint('yes')\\n\\telse:\\n\\t\\tprint('no')\\n\",\n \"def solve():\\n\\tn = int(input())\\n\\t(s, t) = (input(), input())\\n\\tif s == t:\\n\\t\\tunique_letters = set(s)\\n\\t\\tif len(unique_letters) == n:\\n\\t\\t\\tprint('No')\\n\\t\\telse:\\n\\t\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tdifferent = []\\n\\t\\tfor i in range(n):\\n\\t\\t\\tif s[i] != t[i]:\\n\\t\\t\\t\\tdifferent.append(i)\\n\\t\\tif len(different) != 2:\\n\\t\\t\\tprint('No')\\n\\t\\telif s[different[0]] == s[different[1]] and t[different[1]] == t[different[0]]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\nk = int(input())\\nfor i in range(k):\\n\\tsolve()\\n\",\n \"for u in range(int(input())):\\n\\tn = int(input())\\n\\ts = list(input())\\n\\tt = list(input())\\n\\tpos = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tpos.append(i)\\n\\tif len(pos) != 2:\\n\\t\\tprint('No')\\n\\telse:\\n\\t\\t(s[pos[0]], t[pos[1]]) = (t[pos[1]], s[pos[0]])\\n\\t\\tif s == t:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\",\n \"k = int(input())\\n\\ndef replace(s1, s2):\\n\\tif s1 == s2:\\n\\t\\treturn 'YES'\\n\\telse:\\n\\t\\tdif = 0\\n\\t\\tl = []\\n\\t\\tfor j in range(n):\\n\\t\\t\\tif s1[j] != s2[j]:\\n\\t\\t\\t\\tdif += 1\\n\\t\\t\\t\\tl.append(j)\\n\\t\\tif dif == 2:\\n\\t\\t\\t(a, b) = (l[0], l[1])\\n\\t\\t\\tif s1[a] == s1[b] and s2[a] == s2[b]:\\n\\t\\t\\t\\treturn 'YES'\\n\\t\\treturn 'NO'\\nfor i in range(k):\\n\\tn = int(input())\\n\\ts1 = list(input())\\n\\ts2 = list(input())\\n\\tprint(replace(s1, s2))\\n\",\n \"from collections import Counter\\nk = int(input())\\nfor i in range(k):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tc = Counter(s + t)\\n\\tf = False\\n\\tfor key in c:\\n\\t\\tif c[key] % 2 != 0:\\n\\t\\t\\tprint('No')\\n\\t\\t\\tf = True\\n\\t\\t\\tbreak\\n\\tif f:\\n\\t\\tcontinue\\n\\telse:\\n\\t\\tprint('Yes')\\n\\top = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] == t[i]:\\n\\t\\t\\tcontinue\\n\\t\\tf = True\\n\\t\\tif t[i] in t[i + 1:]:\\n\\t\\t\\tidx = t[i + 1:].index(t[i]) + i + 1\\n\\t\\t\\top.append((i + 1, idx + 1))\\n\\t\\t\\t(s, t) = (s[:i] + t[idx] + s[i + 1:], t[:idx] + s[i] + t[idx + 1:])\\n\\t\\telse:\\n\\t\\t\\tidx = s[i + 1:].index(t[i]) + i + 1\\n\\t\\t\\top.append((idx + 1, i + 1 + 1))\\n\\t\\t\\top.append((i + 1, i + 1 + 1))\\n\\t\\t\\t(s, t) = (s[:idx] + t[i + 1] + s[idx + 1:], t[:i + 1] + s[idx] + t[i + 2:])\\n\\t\\t\\t(s, t) = (s[:i] + t[i + 1] + s[i + 1:], t[:i + 1] + s[i] + t[i + 2:])\\n\\tif not f:\\n\\t\\tprint('1')\\n\\t\\tprint('1 1')\\n\\telse:\\n\\t\\tprint(len(op))\\n\\t\\tfor sw in op:\\n\\t\\t\\tprint(*sw)\\n\",\n \"for _ in range(int(input())):\\n\\tn = int(input())\\n\\ta = input()\\n\\tb = input()\\n\\tcount = 0\\n\\tz = []\\n\\tfor i in range(n):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\tcount += 1\\n\\t\\t\\tz.append([a[i], b[i]])\\n\\tif count == 2 and z[0] == z[1]:\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"for _ in range(int(input())):\\n\\tn = int(input())\\n\\ts = list(input())\\n\\tt = list(input())\\n\\tx = 0\\n\\tdiff = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tx += 1\\n\\t\\t\\tdiff.append(i)\\n\\t\\tif x == 3:\\n\\t\\t\\tbreak\\n\\tif x >= 3 or x < 2:\\n\\t\\tprint('No')\\n\\telif s[diff[0]] == s[diff[1]] and t[diff[0]] == t[diff[1]]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"from datetime import datetime\\nimport math\\n\\nclass Read:\\n\\n\\t@staticmethod\\n\\tdef string():\\n\\t\\treturn input()\\n\\n\\t@staticmethod\\n\\tdef int():\\n\\t\\treturn int(input())\\n\\n\\t@staticmethod\\n\\tdef list(sep=' '):\\n\\t\\treturn input().split(sep)\\n\\n\\t@staticmethod\\n\\tdef list_int(sep=' '):\\n\\t\\treturn list(map(int, input().split(sep)))\\n\\ndef solve():\\n\\tn = Read.int()\\n\\ts = input()\\n\\tt = input()\\n\\tsa = []\\n\\tta = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tsa.append(s[i])\\n\\t\\t\\tta.append(t[i])\\n\\tif len(sa) == 0:\\n\\t\\tprint('YES')\\n\\telif len(sa) == 2 and sa[0] == sa[1] and (ta[0] == ta[1]):\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\nquery_count = Read.int()\\nwhile query_count:\\n\\tquery_count -= 1\\n\\tsolve()\\n\",\n \"q = int(input())\\nfor i in range(q):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\ts1 = list(s)\\n\\tt1 = list(t)\\n\\tj = 0\\n\\tk = n - 1\\n\\twhile j <= k:\\n\\t\\tif s1[j] == t1[j]:\\n\\t\\t\\tj += 1\\n\\t\\tif s1[k] == t1[k]:\\n\\t\\t\\tk -= 1\\n\\t\\tif s1[j] != t1[j] and s1[k] != t1[k]:\\n\\t\\t\\tbreak\\n\\tif j == k:\\n\\t\\tprint('NO')\\n\\telse:\\n\\t\\ta = s1[j]\\n\\t\\ts1[j] = t1[k]\\n\\t\\tt1[k] = a\\n\\t\\tt2 = ''.join(t1)\\n\\t\\ts2 = ''.join(s1)\\n\\t\\tif s2 == t2:\\n\\t\\t\\tprint('YES')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\",\n \"t = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tc = 0\\n\\tindx = []\\n\\tfor j in range(0, n):\\n\\t\\tif s[j] != t[j]:\\n\\t\\t\\tindx.append(j)\\n\\t\\t\\tc += 1\\n\\t\\tif c > 2:\\n\\t\\t\\tbreak\\n\\tif c == 2:\\n\\t\\tif s[indx[0]] == s[indx[1]] and t[indx[0]] == t[indx[1]]:\\n\\t\\t\\tprint('YES')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"k = int(input())\\nresult = []\\nfor i in range(k):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tsum = 0\\n\\ttl = []\\n\\tsave = ''\\n\\ts1 = list(s1)\\n\\ts2 = list(s2)\\n\\tfor t in range(n):\\n\\t\\tif s1[t] != s2[t]:\\n\\t\\t\\tsum += 1\\n\\t\\t\\ttl.append(t)\\n\\tif sum == 1:\\n\\t\\td = tl[0]\\n\\t\\tsave = s1[d]\\n\\t\\ts1[d] = s2[d]\\n\\t\\ts2[d] = save\\n\\t\\tif s1 == s2:\\n\\t\\t\\tresult.append('yes')\\n\\t\\telse:\\n\\t\\t\\tresult.append('no')\\n\\telif sum == 2:\\n\\t\\td1 = tl[0]\\n\\t\\td2 = tl[1]\\n\\t\\tsave1 = s1[d1]\\n\\t\\ts1[d1] = s2[d2]\\n\\t\\ts2[d2] = save1\\n\\t\\tif s1 == s2:\\n\\t\\t\\tresult.append('yes')\\n\\t\\telse:\\n\\t\\t\\tresult.append('no')\\n\\telse:\\n\\t\\tresult.append('no')\\nfor y in range(k):\\n\\tprint(result[y])\\n\",\n \"import sys\\nsys.setrecursionlimit(10 ** 8)\\ninput = sys.stdin.readline\\norda = ord('a')\\nk = int(input())\\nfor i in range(k):\\n\\tn = int(input())\\n\\ts = input().rstrip()\\n\\tt = input().rstrip()\\n\\tsnum = []\\n\\ttnum = []\\n\\talpha = [0] * 26\\n\\tfor (i, ch) in enumerate(s):\\n\\t\\talpha[ord(ch) - orda] += 1\\n\\t\\tsnum.append(ord(ch) - orda)\\n\\tfor (i, ch) in enumerate(t):\\n\\t\\talpha[ord(ch) - orda] += 1\\n\\t\\ttnum.append(ord(ch) - orda)\\n\\tok = True\\n\\tfor i in range(26):\\n\\t\\tif alpha[i] % 2 == 1:\\n\\t\\t\\tok = False\\n\\t\\t\\tbreak\\n\\tif ok:\\n\\t\\tprint('Yes')\\n\\t\\tans = []\\n\\t\\tfor i in range(n):\\n\\t\\t\\tif snum[i] == tnum[i]:\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\telif tnum[i + 1:].count(tnum[i]) > 0:\\n\\t\\t\\t\\tindex = tnum[i + 1:].index(tnum[i]) + i + 1\\n\\t\\t\\t\\tans.append((i, index))\\n\\t\\t\\t\\t(snum[i], tnum[index]) = (tnum[index], snum[i])\\n\\t\\t\\telse:\\n\\t\\t\\t\\tindex = snum[i + 1:].index(tnum[i]) + i + 1\\n\\t\\t\\t\\tans.append((index, n - 1))\\n\\t\\t\\t\\tans.append((i, n - 1))\\n\\t\\t\\t\\t(snum[i], snum[index], tnum[n - 1]) = (snum[index], tnum[n - 1], snum[i])\\n\\t\\tprint(len(ans))\\n\\t\\tret = ''\\n\\t\\tfor (a, b) in ans:\\n\\t\\t\\tprint(a + 1, b + 1)\\n\\telse:\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\",\n \"k = int(input())\\nfor _ in range(k):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\t(c, c1, c2) = (0, [], [])\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tc += 1\\n\\t\\t\\tc1.append(s[i])\\n\\t\\t\\tc2.append(t[i])\\n\\tif c == 2 and len(set(c1)) == 1 and (len(set(c2)) == 1):\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"import collections\\nk = int(input())\\nfor kk in range(k):\\n\\tn = int(input())\\n\\ts = list(input())\\n\\tt = list(input())\\n\\toperations = list()\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tok = False\\n\\t\\t\\tfor j in range(i + 1, n):\\n\\t\\t\\t\\tif s[i] == s[j]:\\n\\t\\t\\t\\t\\tok = True\\n\\t\\t\\t\\t\\toperations.append((j, i))\\n\\t\\t\\t\\t\\t(s[j], t[i]) = (t[i], s[j])\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\t\\tif s[i] == t[j] and i + 1 < n:\\n\\t\\t\\t\\t\\tok = True\\n\\t\\t\\t\\t\\toperations.append((i + 1, j))\\n\\t\\t\\t\\t\\t(t[j], s[i + 1]) = (s[i + 1], t[j])\\n\\t\\t\\t\\t\\toperations.append((i + 1, i))\\n\\t\\t\\t\\t\\t(s[i + 1], t[i]) = (t[i], s[i + 1])\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\tif not ok:\\n\\t\\t\\t\\toperations = None\\n\\t\\t\\t\\tbreak\\n\\tif operations is None:\\n\\t\\tprint('No')\\n\\telse:\\n\\t\\tassert s == t\\n\\t\\tprint('Yes')\\n\\t\\tprint(len(operations))\\n\\t\\tfor (i, j) in operations:\\n\\t\\t\\tprint(1 + i, 1 + j)\\n\",\n \"from sys import stdin\\nfrom collections import Counter\\n\\ndef check(x):\\n\\tsor = x.most_common()\\n\\ttop = sor[:2]\\n\\tbot = sor[:-3:-1]\\n\\tif (top[0][1] == 2) & (bot[0][1] == -2):\\n\\t\\tif top[1][1] == bot[1][1] == 0:\\n\\t\\t\\treturn True\\n\\t\\tif (top[1][1] == -2) & (bot[1][1] == 2):\\n\\t\\t\\treturn True\\n\\treturn False\\n\\ndef doublecheck(a, b, l):\\n\\td = 0\\n\\tfor i in range(l):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\td += 1\\n\\t\\t\\tif d > 2:\\n\\t\\t\\t\\treturn False\\n\\treturn True\\nfor _ in range(int(stdin.readline())):\\n\\tl = int(stdin.readline())\\n\\ts1 = stdin.readline().strip()\\n\\ts2 = stdin.readline().strip()\\n\\tif s1 == s2:\\n\\t\\tprint('Yes')\\n\\t\\tcontinue\\n\\ta = Counter(s1)\\n\\tb = Counter(s2)\\n\\ta.subtract(b)\\n\\tif check(a):\\n\\t\\tif doublecheck(s1, s2, l):\\n\\t\\t\\tprint('Yes')\\n\\t\\t\\tcontinue\\n\\tprint('No')\\n\",\n \"k = int(input())\\nwhile k:\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\ta = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\ta.append(i)\\n\\tif len(a) == 2 and s[a[0]] == s[a[1]] and (t[a[0]] == t[a[1]]):\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\\tk -= 1\\n\",\n \"k = int(input())\\nfor kk in range(k):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\ti = None\\n\\tj = None\\n\\tok = True\\n\\tfor (l, (ss, tt)) in enumerate(zip(s, t)):\\n\\t\\tif ss != tt:\\n\\t\\t\\tif i is None:\\n\\t\\t\\t\\ti = l\\n\\t\\t\\telif j is None:\\n\\t\\t\\t\\tj = l\\n\\t\\t\\telse:\\n\\t\\t\\t\\tok = False\\n\\t\\t\\t\\tbreak\\n\\tif ok and (i is None and j is None or (i is not None and j is not None and (s[i] == s[j]) and (t[j] == t[i]))):\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"def main():\\n\\n\\tdef solve():\\n\\t\\tn = int(input())\\n\\t\\tss = input()\\n\\t\\ttt = input()\\n\\t\\tdiffpos = []\\n\\t\\tfor i in range(n):\\n\\t\\t\\tif ss[i] != tt[i]:\\n\\t\\t\\t\\tdiffpos.append(i)\\n\\t\\tif len(diffpos) > 2 or len(diffpos) == 1:\\n\\t\\t\\tprint('No')\\n\\t\\t\\treturn\\n\\t\\tif len(diffpos) == 0:\\n\\t\\t\\tprint('Yes')\\n\\t\\t\\treturn\\n\\t\\tif ss[diffpos[0]] == ss[diffpos[1]] and tt[diffpos[0]] == tt[diffpos[1]]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\\tq = int(input())\\n\\tfor _ in range(q):\\n\\t\\tsolve()\\nmain()\\n\",\n \"k = int(input(''))\\nfor tc in range(k):\\n\\tn = int(input(''))\\n\\ts = input('')\\n\\tt = input('')\\n\\toop_pair = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\toop_pair.append([s[i], t[i]])\\n\\tif len(oop_pair) == 2:\\n\\t\\tif oop_pair[0] == oop_pair[1]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"import sys\\ninput = sys.stdin.readline\\nN = int(input())\\nfor _ in range(N):\\n\\tk = int(input())\\n\\ts = list(input())[:-1]\\n\\tt = list(input())[:-1]\\n\\tx = -1\\n\\ty = -1\\n\\tf = 0\\n\\tfor i in range(k):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tif x == -1:\\n\\t\\t\\t\\tx = i\\n\\t\\t\\telif y == -1:\\n\\t\\t\\t\\ty = i\\n\\t\\t\\telse:\\n\\t\\t\\t\\tf = 1\\n\\tif f or (x != -1 and y == -1):\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\\tif s[x] == s[y] and t[x] == t[y]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nwhile t > 0:\\n\\tn = int(input())\\n\\ta = input()\\n\\tb = input()\\n\\tind = []\\n\\tfor i in range(0, len(a)):\\n\\t\\tif a[i] == b[i]:\\n\\t\\t\\tpass\\n\\t\\telse:\\n\\t\\t\\tind.append(i)\\n\\tif len(ind) > 2 or len(ind) == 1:\\n\\t\\tprint('No')\\n\\telif a[ind[0]] == a[ind[1]] and b[ind[0]] == b[ind[1]]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\\tt -= 1\\n\",\n \"def solve(s, t):\\n\\tdiff = 0\\n\\ti1 = -1\\n\\ti2 = -1\\n\\tfor i in range(len(s)):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tif diff == 0:\\n\\t\\t\\t\\ti1 = i\\n\\t\\t\\telse:\\n\\t\\t\\t\\ti2 = i\\n\\t\\t\\tdiff += 1\\n\\t\\t\\tif diff > 2:\\n\\t\\t\\t\\treturn 0\\n\\tif diff == 1:\\n\\t\\treturn 0\\n\\tif diff == 0:\\n\\t\\treturn 1\\n\\tif s[i1] == s[i2] and t[i1] == t[i2]:\\n\\t\\treturn 1\\n\\treturn 0\\nt = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tif solve(s, t) == 0:\\n\\t\\tprint('No')\\n\\telse:\\n\\t\\tprint('Yes')\\n\",\n \"from collections import Counter, deque\\nimport sys\\nimport math\\nfrom functools import reduce\\n\\ndef factors(n):\\n\\treturn set(reduce(list.__add__, ([i, n // i] for i in range(1, int(n ** 0.5) + 1) if n % i == 0)))\\n\\ndef li():\\n\\treturn [int(i) for i in input().rstrip('\\\\n').split(' ')]\\n\\ndef st():\\n\\treturn input().rstrip('\\\\n')\\n\\ndef val():\\n\\treturn int(input())\\nfor _ in range(val()):\\n\\tn = val()\\n\\ts1 = st()\\n\\ts2 = st()\\n\\tcnt = Counter(s1) + Counter(s2)\\n\\tans = 'YES'\\n\\tfor i in cnt:\\n\\t\\tif cnt[i] & 1:\\n\\t\\t\\tans = 'NO'\\n\\t\\t\\tbreak\\n\\tprint(ans)\\n\\tif ans[0] == 'N':\\n\\t\\tcontinue\\n\\ts1 = list(s1)\\n\\ts2 = list(s2)\\n\\tans = []\\n\\tfor i in range(len(s1)):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\tcurr = 0\\n\\t\\t\\tfor j in range(i + 1, len(s1)):\\n\\t\\t\\t\\tif s1[j] == s1[i]:\\n\\t\\t\\t\\t\\ts1[j] = s2[i]\\n\\t\\t\\t\\t\\tans.append([j, i])\\n\\t\\t\\t\\t\\tcurr = 1\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\tif curr:\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\tfor j in range(i + 1, len(s2)):\\n\\t\\t\\t\\tif s2[j] == s1[i]:\\n\\t\\t\\t\\t\\tans.append([j, j])\\n\\t\\t\\t\\t\\tans.append([j, i])\\n\\t\\t\\t\\t\\t(s1[j], s2[j]) = (s2[j], s1[j])\\n\\t\\t\\t\\t\\ts1[j] = s2[i]\\n\\t\\t\\t\\t\\tcurr = 1\\n\\t\\t\\t\\t\\tbreak\\n\\tprint(len(ans))\\n\\tfor i in ans:\\n\\t\\tprint(i[0] + 1, i[1] + 1)\\n\",\n \"import sys\\n\\ndef get(s, t):\\n\\tarr = [0] * 26\\n\\tans = []\\n\\tn = len(s)\\n\\tfor i in range(n):\\n\\t\\tarr[ord(s[i]) - 97] += 1\\n\\t\\tarr[ord(t[i]) - 97] += 1\\n\\tfor i in range(26):\\n\\t\\tif arr[i] % 2 != 0:\\n\\t\\t\\treturn False\\n\\tfor i in range(n):\\n\\t\\tif s[i] == t[i]:\\n\\t\\t\\tpass\\n\\t\\telse:\\n\\t\\t\\tz = True\\n\\t\\t\\tfor k in range(i + 1, n):\\n\\t\\t\\t\\tif s[k] == s[i]:\\n\\t\\t\\t\\t\\tz = False\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\tif not z:\\n\\t\\t\\t\\t(t[i], s[k]) = (s[k], t[i])\\n\\t\\t\\t\\tans.append([k, i])\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\tfor k in range(i + 1, n):\\n\\t\\t\\t\\tif t[k] == s[i]:\\n\\t\\t\\t\\t\\tz = False\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\tif not z:\\n\\t\\t\\t\\tans.append([n - 1, k])\\n\\t\\t\\t\\t(s[n - 1], t[k]) = (t[k], s[n - 1])\\n\\t\\t\\t\\tans.append([n - 1, i])\\n\\t\\t\\t\\t(s[n - 1], t[i]) = (t[i], s[n - 1])\\n\\treturn ans\\nt = int(sys.stdin.readline())\\nfor _ in range(t):\\n\\tn = int(sys.stdin.readline())\\n\\ts = list(sys.stdin.readline())[:-1]\\n\\tt = list(sys.stdin.readline())[:-1]\\n\\ta = get(s, t)\\n\\tif a:\\n\\t\\tprint('YES')\\n\\t\\tprint(len(a))\\n\\t\\tfor i in range(len(a)):\\n\\t\\t\\tprint(a[i][0] + 1, a[i][1] + 1)\\n\\telse:\\n\\t\\tprint('no')\\n\",\n \"for _ in range(int(input())):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tprev1 = ''\\n\\tprev2 = ''\\n\\tc = 1\\n\\tflag = 1\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i] and prev1 == '' and (prev2 == ''):\\n\\t\\t\\tprev1 = s[i]\\n\\t\\t\\tprev2 = t[i]\\n\\t\\telif s[i] != t[i] and prev1 == s[i] and (prev2 == t[i]):\\n\\t\\t\\tc += 1\\n\\t\\t\\tif c > 2:\\n\\t\\t\\t\\tflag = 0\\n\\t\\t\\t\\tbreak\\n\\t\\telif s[i] != t[i]:\\n\\t\\t\\tif prev1 != s[i] or prev2 != t[i]:\\n\\t\\t\\t\\tc += 1\\n\\t\\t\\tc += 1\\n\\t\\t\\tif c > 2:\\n\\t\\t\\t\\tflag = 0\\n\\t\\t\\t\\tbreak\\n\\tif c != 2:\\n\\t\\tflag = 0\\n\\tprint(['NO', 'YES'][flag])\\n\",\n \"from collections import Counter\\nr = []\\nfor jwwej in range(int(input())):\\n\\tn = int(input())\\n\\ts = list(input())\\n\\tt = list(input())\\n\\tg = 0\\n\\tif s == t:\\n\\t\\tff = list(Counter(s).values())\\n\\t\\tff.sort()\\n\\t\\tif ff[len(ff) - 1] > 1:\\n\\t\\t\\tr.append('YES')\\n\\t\\telse:\\n\\t\\t\\tr.append('NO')\\n\\telse:\\n\\t\\tfs = []\\n\\t\\tfr = []\\n\\t\\tfor i in range(0, n):\\n\\t\\t\\tif s[i] != t[i]:\\n\\t\\t\\t\\tfs.append(s[i])\\n\\t\\t\\t\\tfr.append(t[i])\\n\\t\\t\\tif len(fs) > 2:\\n\\t\\t\\t\\tr.append('NO')\\n\\t\\t\\t\\tbreak\\n\\t\\tif len(fs) == 1:\\n\\t\\t\\tr.append('NO')\\n\\t\\telif len(fs) == 2:\\n\\t\\t\\tif fs[0] == fs[1] and fr[0] == fr[1]:\\n\\t\\t\\t\\tr.append('YES')\\n\\t\\t\\telse:\\n\\t\\t\\t\\tr.append('NO')\\nfor i in r:\\n\\tprint(i)\\n\",\n \"import math\\nt = int(input())\\nfor _ in range(t):\\n\\tk = int(input())\\n\\tans = False\\n\\ts1 = input()\\n\\ts2 = input()\\n\\ts1ptr = -1\\n\\tfor i in range(k):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\tif s1ptr == -1:\\n\\t\\t\\t\\ts1ptr = i\\n\\t\\t\\telse:\\n\\t\\t\\t\\ttemp = s2[i]\\n\\t\\t\\t\\ts2 = s2[:i] + s1[s1ptr] + s2[i + 1:]\\n\\t\\t\\t\\tif s1ptr == 0:\\n\\t\\t\\t\\t\\ts1 = temp + s1[s1ptr + 1:]\\n\\t\\t\\t\\telse:\\n\\t\\t\\t\\t\\ts1 = s1[:s1ptr] + temp + s1[s1ptr + 1:]\\n\\t\\t\\t\\tbreak\\n\\tif s1 == s2:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"k = int(input())\\n\\ndef solve(n, s, t):\\n\\td = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\td.append(i)\\n\\tif len(d) == 2 and s[d[0]] == s[d[1]] and (t[d[1]] == t[d[0]]):\\n\\t\\treturn 'Yes'\\n\\treturn 'No'\\nfor _ in range(k):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tprint(solve(n, s, t))\\n\",\n \"k = int(input())\\nfor da in range(k):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\ta = []\\n\\tfor i in range(n):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\ta.append(i)\\n\\tif len(a) == 0:\\n\\t\\tprint('Yes')\\n\\t\\tcontinue\\n\\tif len(a) != 2:\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\\tif s1[a[0]] == s1[a[1]] and s2[a[0]] == s2[a[1]]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"import math\\nt = int(input())\\nfor g in range(0, t):\\n\\tn = int(input())\\n\\ta = input()\\n\\tb = input()\\n\\tdiff = 0\\n\\tchar1 = []\\n\\tchar2 = []\\n\\tbreaks = 0\\n\\tfor i in range(0, n):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\tdiff += 1\\n\\t\\t\\tchar1.append(a[i])\\n\\t\\t\\tchar2.append(b[i])\\n\\t\\tif diff > 2:\\n\\t\\t\\tprint('No')\\n\\t\\t\\tbreaks = 1\\n\\t\\t\\tbreak\\n\\tif breaks == 0:\\n\\t\\tif diff != 2:\\n\\t\\t\\tprint('No')\\n\\t\\telse:\\n\\t\\t\\tchar1.sort()\\n\\t\\t\\tchar2.sort()\\n\\t\\t\\tif char1[0] == char1[1] and char2[1] == char2[0]:\\n\\t\\t\\t\\tprint('Yes')\\n\\t\\t\\telse:\\n\\t\\t\\t\\tprint('No')\\n\",\n \"t = int(input())\\nwhile t:\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tl1 = []\\n\\tl2 = []\\n\\tfor i in range(len(s1)):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\tl1.append(s1[i])\\n\\t\\t\\tl2.append(s2[i])\\n\\tif (len(set(l1)) == 1 and len(set(l2)) == 1) and (len(l1) == 2 and len(l2) == 2):\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\\tt -= 1\\n\",\n \"from math import floor, ceil\\nfrom collections import defaultdict\\nt = int(input())\\nfor _ in range(t):\\n\\tn = int(input())\\n\\ta = list(input())\\n\\tb = list(input())\\n\\tus = defaultdict(set)\\n\\tns = defaultdict(set)\\n\\td = defaultdict(lambda : 0)\\n\\tans = list()\\n\\tdone = False\\n\\tfor c in a + b:\\n\\t\\td[c] += 1\\n\\tfor k in d:\\n\\t\\tif d[k] % 2 != 0:\\n\\t\\t\\tprint('No')\\n\\t\\t\\tdone = True\\n\\t\\t\\tbreak\\n\\tif done:\\n\\t\\tcontinue\\n\\tfor (i, c) in enumerate(a):\\n\\t\\tus[c].add(i)\\n\\tfor (i, c) in enumerate(b):\\n\\t\\tns[c].add(i)\\n\\tfor i in range(n - 1):\\n\\t\\tfor k in us:\\n\\t\\t\\tus[k].discard(i)\\n\\t\\tfor k in ns:\\n\\t\\t\\tns[k].discard(i)\\n\\t\\tif a[i] == b[i]:\\n\\t\\t\\tcontinue\\n\\t\\tif len(us[a[i]]) > 0:\\n\\t\\t\\tpos = list(us[a[i]])[0]\\n\\t\\t\\tus[b[i]].add(pos)\\n\\t\\t\\ta[pos] = b[i]\\n\\t\\t\\tb[i] = a[i]\\n\\t\\t\\tus[a[i]].discard(pos)\\n\\t\\t\\tans.append((pos + 1, i + 1))\\n\\t\\telse:\\n\\t\\t\\tpos = list(ns[a[i]])[0]\\n\\t\\t\\tns[a[i + 1]].add(pos)\\n\\t\\t\\tus[b[i]].add(i + 1)\\n\\t\\t\\tb[pos] = a[i + 1]\\n\\t\\t\\ta[i + 1] = b[i]\\n\\t\\t\\tb[i] = a[i]\\n\\t\\t\\tns[a[i]].discard(pos)\\n\\t\\t\\tans.extend([(i + 1 + 1, pos + 1), (i + 1 + 1, i + 1)])\\n\\tprint('Yes')\\n\\tprint(len(ans))\\n\\tfor (a, b) in ans:\\n\\t\\tprint(a, b)\\n\",\n \"for i in range(int(input())):\\n\\tn = int(input())\\n\\ts = input()\\n\\ts = list(s)\\n\\tt = input()\\n\\tt = list(t)\\n\\tcount = 0\\n\\tflag = 0\\n\\tls = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tif count < 2:\\n\\t\\t\\t\\tls.append(i)\\n\\t\\t\\t\\tcount += 1\\n\\t\\t\\telse:\\n\\t\\t\\t\\tprint('NO')\\n\\t\\t\\t\\tflag = 1\\n\\t\\t\\t\\tbreak\\n\\tif flag == 0:\\n\\t\\tif len(ls) == 2:\\n\\t\\t\\t(s[ls[0]], t[ls[1]]) = (t[ls[1]], s[ls[0]])\\n\\t\\t\\tif ''.join(s) == ''.join(t):\\n\\t\\t\\t\\tprint('YES')\\n\\t\\t\\telse:\\n\\t\\t\\t\\tprint('NO')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\",\n \"from sys import stdin, stdout\\nfrom collections import Counter, deque\\nfrom bisect import bisect_left\\nfrom itertools import product\\nT = int(input())\\nfor _ in range(T):\\n\\tn = int(input())\\n\\t(a, b) = (list(input()), list(input()))\\n\\tcc = Counter(a + b)\\n\\tif any([u % 2 for u in cc.values()]):\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\\tres = []\\n\\tfor i in range(n):\\n\\t\\tif a[i] == b[i]:\\n\\t\\t\\tcontinue\\n\\t\\tif a[i] in a[i + 1:]:\\n\\t\\t\\tp = a[i + 1:].index(a[i])\\n\\t\\t\\t(b[i], a[i + p + 1]) = (a[i + p + 1], b[i])\\n\\t\\t\\tres.append((i + p + 1, i))\\n\\t\\telse:\\n\\t\\t\\tp = b[i + 1:].index(a[i])\\n\\t\\t\\t(a[i + 1], b[i + p + 1]) = (b[i + p + 1], a[i + 1])\\n\\t\\t\\t(a[i + 1], b[i]) = (b[i], a[i + 1])\\n\\t\\t\\tres.append((i + 1, i + p + 1))\\n\\t\\t\\tres.append((i + 1, i))\\n\\tprint('Yes')\\n\\tprint(len(res))\\n\\tfor (u, v) in res:\\n\\t\\tprint(str(u + 1) + ' ' + str(v + 1))\\n\",\n \"for z in range(int(input())):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tind = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tind.append(i)\\n\\tif len(ind) != 2 and len(ind) != 0:\\n\\t\\tprint('NO')\\n\\telif len(ind) == 2 and (s[ind[0]] != s[ind[1]] or t[ind[1]] != t[ind[0]]):\\n\\t\\tprint('NO')\\n\\telse:\\n\\t\\tprint('YES')\\n\",\n \"def solve(s1, s2):\\n\\tL = [0] * 26\\n\\tn = len(s1)\\n\\tsolution = []\\n\\tfor i in s1:\\n\\t\\tL[ord(i) - 97] += 1\\n\\tfor j in s2:\\n\\t\\tL[ord(j) - 97] += 1\\n\\tfor i in L:\\n\\t\\tif i % 2:\\n\\t\\t\\treturn -1\\n\\ts1 = list(s1)\\n\\ts2 = list(s2)\\n\\tfor i in range(n):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\tc = True\\n\\t\\t\\tfor j in range(i + 1, n):\\n\\t\\t\\t\\tif s1[i] == s1[j]:\\n\\t\\t\\t\\t\\tc = False\\n\\t\\t\\t\\t\\t(s1[j], s2[i]) = (s2[i], s1[j])\\n\\t\\t\\t\\t\\tsolution.append((j + 1, i + 1))\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\tif c:\\n\\t\\t\\t\\tfor j in range(i + 1, n):\\n\\t\\t\\t\\t\\tif s1[i] == s2[j]:\\n\\t\\t\\t\\t\\t\\t(s1[j], s2[j]) = (s2[j], s1[j])\\n\\t\\t\\t\\t\\t\\tsolution.append((j + 1, j + 1))\\n\\t\\t\\t\\t\\t\\t(s1[j], s2[i]) = (s2[i], s1[j])\\n\\t\\t\\t\\t\\t\\tsolution.append((j + 1, i + 1))\\n\\t\\t\\t\\t\\t\\tbreak\\n\\treturn solution\\nfor i in ' ' * int(input()):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\ts = solve(s1, s2)\\n\\tif s == -1:\\n\\t\\tprint('No')\\n\\telse:\\n\\t\\tprint('Yes')\\n\\t\\tprint(len(s))\\n\\t\\tfor i in s:\\n\\t\\t\\t(a, b) = i\\n\\t\\t\\tprint(a, b)\\n\",\n \"q = int(input())\\nfor _ in range(q):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tra = 0\\n\\t(a, c) = ('', '')\\n\\tok = True\\n\\tfor i in range(n):\\n\\t\\tif ra > 2:\\n\\t\\t\\tbreak\\n\\t\\telif s[i] != t[i]:\\n\\t\\t\\ta += s[i]\\n\\t\\t\\tc += t[i]\\n\\t\\t\\tra += 1\\n\\tif ra > 2:\\n\\t\\tok = False\\n\\tif ra < 2 or not ok:\\n\\t\\tprint('No')\\n\\telif a[0] == a[1] and c[0] == c[1] and ok:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"for _ in range(int(input())):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tlst = list()\\n\\tfor i in range(n):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\tlst.append(i)\\n\\tif len(lst) == 2 and s1[lst[0]] == s1[lst[1]] and (s2[lst[0]] == s2[lst[1]]):\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"k = int(input())\\nfor _ in range(k):\\n\\tn = int(input())\\n\\t(s, t) = (input(), input())\\n\\t(flag, diff1, diff2) = (0, '', '')\\n\\tfor (c1, c2) in zip(s, t):\\n\\t\\tif c1 != c2:\\n\\t\\t\\tif not flag:\\n\\t\\t\\t\\tflag = 1\\n\\t\\t\\t\\tdiff1 = c1\\n\\t\\t\\t\\tdiff2 = c2\\n\\t\\t\\telif flag == 1:\\n\\t\\t\\t\\tif c1 != diff1 or c2 != diff2:\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\t\\tflag = 2\\n\\t\\t\\telse:\\n\\t\\t\\t\\tbreak\\n\\telse:\\n\\t\\tprint('Yes' if flag == 2 else 'No')\\n\\t\\tcontinue\\n\\tprint('No')\\n\",\n \"for n in range(int(input())):\\n\\tc = int(input())\\n\\tg = 0\\n\\tab = ''\\n\\tba = ''\\n\\ta = list(input())\\n\\tb = list(input())\\n\\tif c == 2:\\n\\t\\ta = set(a)\\n\\t\\tb = set(b)\\n\\t\\tif len(a ^ b) == 2:\\n\\t\\t\\tprint('Yes')\\n\\t\\t\\tcontinue\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\\t\\t\\tcontinue\\n\\tfor i in range(c):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\tg += 1\\n\\t\\t\\tab += a[i]\\n\\t\\t\\tba += b[i]\\n\\tif g != 0 and g != 2:\\n\\t\\tprint('No')\\n\\telif g == 2:\\n\\t\\tif ab[0] + ba[1] == ab[1] + ba[0]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\\telse:\\n\\t\\tprint('Yes')\\n\",\n \"for _ in range(int(input())):\\n\\tlength = int(input())\\n\\tstr1 = str(input())\\n\\tstr2 = str(input())\\n\\tindices = []\\n\\tdiff = 0\\n\\tYes = True\\n\\tfor i in range(len(str1)):\\n\\t\\tif str1[i] != str2[i]:\\n\\t\\t\\tdiff += 1\\n\\t\\t\\tindices.append(i)\\n\\t\\tif diff > 2:\\n\\t\\t\\tbreak\\n\\tif diff == 0 or (diff == 2 and str1[indices[0]] == str1[indices[1]] and (str2[indices[1]] == str2[indices[0]])):\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nwhile t > 0:\\n\\tmaxVal = 0\\n\\tn = int(input())\\n\\tst1 = input()\\n\\tst2 = input()\\n\\tlistO1 = []\\n\\tlistO2 = []\\n\\ti = 0\\n\\twhile i < n:\\n\\t\\tif st1[i] != st2[i]:\\n\\t\\t\\tlistO1.append(st1[i])\\n\\t\\t\\tlistO2.append(st2[i])\\n\\t\\ti += 1\\n\\tif len(listO1) == 2 and len(listO2) == 2:\\n\\t\\tif len(set(listO1)) == 1 and len(set(listO2)) == 1:\\n\\t\\t\\tprint('YES')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\\telse:\\n\\t\\tprint('NO')\\n\\tt -= 1\\n\",\n \"tc = int(input())\\nfor t in range(tc):\\n\\tn = int(input())\\n\\ts = [char for char in input()]\\n\\tt = [char for char in input()]\\n\\tfreq = {}\\n\\tfor i in range(n):\\n\\t\\tif s[i] in freq.keys():\\n\\t\\t\\tfreq[s[i]] += 1\\n\\t\\telse:\\n\\t\\t\\tfreq[s[i]] = 1\\n\\t\\tif t[i] in freq.keys():\\n\\t\\t\\tfreq[t[i]] += 1\\n\\t\\telse:\\n\\t\\t\\tfreq[t[i]] = 1\\n\\tisPossible = True\\n\\tfor key in freq.keys():\\n\\t\\tif freq[key] % 2 != 0:\\n\\t\\t\\tisPossible = False\\n\\tif isPossible == False:\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\\tprint('Yes')\\n\\tmoves = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] == t[i]:\\n\\t\\t\\tcontinue\\n\\t\\telse:\\n\\t\\t\\tfound = False\\n\\t\\t\\tfor j in range(i + 1, n):\\n\\t\\t\\t\\tif s[j] == s[i]:\\n\\t\\t\\t\\t\\tmoves.append((j, i))\\n\\t\\t\\t\\t\\ts[j] = t[i]\\n\\t\\t\\t\\t\\tt[i] = s[i]\\n\\t\\t\\t\\t\\tfound = True\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\tif found:\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\tfor j in range(i + 1, n):\\n\\t\\t\\t\\tif t[j] == s[i]:\\n\\t\\t\\t\\t\\tmoves.append((j, j))\\n\\t\\t\\t\\t\\ttemp = s[j]\\n\\t\\t\\t\\t\\ts[j] = t[j]\\n\\t\\t\\t\\t\\tt[j] = temp\\n\\t\\t\\t\\t\\tmoves.append((j, i))\\n\\t\\t\\t\\t\\ts[j] = t[i]\\n\\t\\t\\t\\t\\tt[i] = s[i]\\n\\t\\t\\t\\t\\tbreak\\n\\tprint(len(moves))\\n\\tfor (i, j) in moves:\\n\\t\\tprint(str(i + 1) + ' ' + str(j + 1))\\n\",\n \"def yes(s, t):\\n\\ts = list(s)\\n\\tt = list(t)\\n\\ta = []\\n\\tfor i in range(len(s)):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\ta.append(i)\\n\\tif len(a) == 0:\\n\\t\\treturn True\\n\\telif len(a) == 1 or len(a) > 2:\\n\\t\\treturn False\\n\\telif s[a[0]] == s[a[1]] and t[a[0]] == t[a[1]]:\\n\\t\\treturn True\\n\\telse:\\n\\t\\treturn False\\nfor i in range(int(input())):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tif yes(t, s):\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"for _ in range(int(input())):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\td = dict()\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i] and (s[i], t[i]) not in d:\\n\\t\\t\\td[s[i], t[i]] = 1\\n\\t\\telif s[i] != t[i] and (s[i], t[i]) in d:\\n\\t\\t\\td[s[i], t[i]] += 1\\n\\tf = 0\\n\\tct = 0\\n\\tfor i in d:\\n\\t\\tif d[i] != 2:\\n\\t\\t\\tf = 1\\n\\t\\tct += 1\\n\\tif f == 0 and ct == 1:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\tb = input()\\n\\tc = input()\\n\\ts = 0\\n\\tm = 0\\n\\tfor j in range(n):\\n\\t\\tif b[j] != c[j] and s == 1:\\n\\t\\t\\tif p == b[j] and q == c[j]:\\n\\t\\t\\t\\tm = 1\\n\\t\\t\\ts += 1\\n\\t\\telif b[j] != c[j] and s != 1:\\n\\t\\t\\ts += 1\\n\\t\\t\\tp = b[j]\\n\\t\\t\\tq = c[j]\\n\\tif s == 1:\\n\\t\\tprint('No')\\n\\telif s > 2:\\n\\t\\tprint('No')\\n\\telif s == 0:\\n\\t\\tprint('Yes')\\n\\telif s == 2:\\n\\t\\tif m == 1:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\",\n \"ntest = int(input())\\nwhile ntest > 0:\\n\\tntest = ntest - 1\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tv = []\\n\\tfor i in range(n):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\tv.append([s1[i], s2[i]])\\n\\tif len(v) != 2 and len(v) != 0:\\n\\t\\tprint('No')\\n\\telif len(v) == 2:\\n\\t\\tif v[0][0] == v[1][0] and v[0][1] == v[1][1]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\\telse:\\n\\t\\tprint('Yes')\\n\",\n \"from collections import defaultdict\\n\\ndef case():\\n\\tn = int(input())\\n\\ts = input()\\n\\ts = [i for i in s]\\n\\tt = input()\\n\\tt = [i for i in t]\\n\\td = defaultdict(int)\\n\\tfor i in s:\\n\\t\\td[i] += 1\\n\\tfor i in t:\\n\\t\\td[i] += 1\\n\\tfor i in d.values():\\n\\t\\tif i % 2:\\n\\t\\t\\tprint('NO')\\n\\t\\t\\treturn\\n\\tans = []\\n\\tfor i in range(n):\\n\\t\\tflag = 0\\n\\t\\tfor j in range(i + 1, n):\\n\\t\\t\\tif s[i] == s[j]:\\n\\t\\t\\t\\t(t[i], s[j]) = (s[j], t[i])\\n\\t\\t\\t\\tans.append([j + 1, i + 1])\\n\\t\\t\\t\\tflag = 1\\n\\t\\t\\t\\tbreak\\n\\t\\tif flag:\\n\\t\\t\\tcontinue\\n\\t\\tfor j in range(i + 1, n):\\n\\t\\t\\tif s[i] == t[j]:\\n\\t\\t\\t\\t(s[j], t[j]) = (t[j], s[j])\\n\\t\\t\\t\\tans.append([j + 1, j + 1])\\n\\t\\t\\t\\t(t[i], s[j]) = (s[j], t[i])\\n\\t\\t\\t\\tans.append([j + 1, i + 1])\\n\\t\\t\\t\\tflag = 1\\n\\t\\t\\t\\tbreak\\n\\t\\tif flag:\\n\\t\\t\\tcontinue\\n\\tprint('YES')\\n\\tprint(len(ans))\\n\\tfor i in ans:\\n\\t\\tprint(*i)\\nfor _ in range(int(input())):\\n\\tcase()\\n\",\n \"def solve(s, t):\\n\\tans = 'NO'\\n\\tinds = []\\n\\tfor i in range(len(s)):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tinds.append(i)\\n\\t\\tif len(inds) > 2:\\n\\t\\t\\tbreak\\n\\tfor i in inds:\\n\\t\\tfor j in inds:\\n\\t\\t\\t(tmp1, tmp2) = (list(s), list(t))\\n\\t\\t\\t(tmp1[i], tmp2[j]) = (t[j], s[i])\\n\\t\\t\\tif tmp1 == tmp2:\\n\\t\\t\\t\\tans = 'YES'\\n\\t\\t\\t\\tbreak\\n\\t\\tif ans == 'YES':\\n\\t\\t\\tbreak\\n\\tprint(ans)\\nk = int(input())\\nfor _ in range(k):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tsolve(s, t)\\n\",\n \"for i in range(int(input())):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\ta = -1\\n\\tb = -1\\n\\tc = 0\\n\\tfor j in range(n):\\n\\t\\tif s[j] != t[j]:\\n\\t\\t\\tc += 1\\n\\t\\t\\tif a == -1:\\n\\t\\t\\t\\ta = j\\n\\t\\t\\telse:\\n\\t\\t\\t\\tb = j\\n\\tif s[a] == s[b] and t[a] == t[b] and (c == 2):\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"for _ in range(int(input())):\\n\\tn = int(input())\\n\\ta = [i for i in input()]\\n\\tb = [i for i in input()]\\n\\td = 0\\n\\tbuc = []\\n\\tfor i in range(n):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\td += 1\\n\\t\\t\\tbuc.append(i)\\n\\tif d == 0:\\n\\t\\tprint('Yes')\\n\\telif d == 1 or d > 2:\\n\\t\\tprint('No')\\n\\telse:\\n\\t\\tans = 'No'\\n\\t\\tif a[buc[0]] == a[buc[1]] and b[buc[0]] == b[buc[1]]:\\n\\t\\t\\tans = 'Yes'\\n\\t\\tprint(ans)\\n\",\n \"t = int(input())\\nfor you in range(t):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tposs = 0\\n\\tlet1 = 0\\n\\tlet2 = 0\\n\\tcount = 0\\n\\tfor i in range(n):\\n\\t\\tif s1[i] != s2[i] and let1 == 0:\\n\\t\\t\\tlet1 = [s1[i], s2[i]]\\n\\t\\telif s1[i] != s2[i] and let2 == 0:\\n\\t\\t\\tlet2 = [s1[i], s2[i]]\\n\\t\\t\\tif let1 == let2:\\n\\t\\t\\t\\tposs = 1\\n\\t\\t\\telse:\\n\\t\\t\\t\\tposs = 0\\n\\t\\t\\t\\tbreak\\n\\t\\telif s1[i] != s2[i]:\\n\\t\\t\\tposs = 0\\n\\t\\t\\tbreak\\n\\tif poss:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\ts = input()\\n\\ttt = input()\\n\\tcnt = 0\\n\\tinds = []\\n\\tfor k in range(n):\\n\\t\\tif s[k] != tt[k]:\\n\\t\\t\\tcnt += 1\\n\\t\\t\\tinds.append(k)\\n\\tif cnt != 2:\\n\\t\\tprint('NO')\\n\\telif s[inds[0]] == s[inds[-1]] and tt[inds[0]] == tt[inds[-1]]:\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"k = int(input())\\nfor _ in range(0, k):\\n\\tsss = []\\n\\tn = int(input())\\n\\tss = input()\\n\\ttt = input()\\n\\ts = [i for i in ss]\\n\\tt = [i for i in tt]\\n\\tfor i in range(0, n):\\n\\t\\tif s[i] == t[i]:\\n\\t\\t\\tcontinue\\n\\t\\tj = ss.find(s[i], i + 1)\\n\\t\\tif j != -1:\\n\\t\\t\\t(s[j], t[i]) = (t[i], s[j])\\n\\t\\t\\tss = ''.join(s)\\n\\t\\t\\ttt = ''.join(t)\\n\\t\\t\\tsss.append([j + 1, i + 1])\\n\\t\\t\\tcontinue\\n\\t\\tj = tt.find(s[i], i + 1)\\n\\t\\tif j != -1:\\n\\t\\t\\t(s[j], t[j]) = (t[j], s[j])\\n\\t\\t\\tsss.append([j + 1, j + 1])\\n\\t\\t\\t(s[j], t[i]) = (t[i], s[j])\\n\\t\\t\\tsss.append([j + 1, i + 1])\\n\\t\\t\\tss = ''.join(s)\\n\\t\\t\\ttt = ''.join(t)\\n\\t\\t\\tcontinue\\n\\t\\tj = tt.find(t[i], i + 1)\\n\\t\\tif j != -1:\\n\\t\\t\\t(s[i], t[j]) = (t[j], s[i])\\n\\t\\t\\tsss.append([i + 1, j + 1])\\n\\t\\t\\tss = ''.join(s)\\n\\t\\t\\ttt = ''.join(t)\\n\\t\\t\\tcontinue\\n\\t\\tj = ss.find(t[i], i + 1)\\n\\t\\tif j != -1:\\n\\t\\t\\t(s[j], t[j]) = (t[j], s[j])\\n\\t\\t\\tsss.append([j + 1, j + 1])\\n\\t\\t\\t(s[i], t[j]) = (t[j], s[i])\\n\\t\\t\\tsss.append([i + 1, j + 1])\\n\\t\\t\\tss = ''.join(s)\\n\\t\\t\\ttt = ''.join(t)\\n\\t\\t\\tcontinue\\n\\tif s == t:\\n\\t\\tprint('YES')\\n\\t\\tprint(len(sss))\\n\\t\\tfor i in sss:\\n\\t\\t\\tprint(*i)\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"n = int(input())\\nfor i in range(n):\\n\\tf = 0\\n\\tz = 0\\n\\tz1 = []\\n\\tn1 = int(input())\\n\\ts = str(input())\\n\\tt = str(input())\\n\\tfor j in range(n1):\\n\\t\\tif s[j] != t[j]:\\n\\t\\t\\tz = z + 1\\n\\t\\t\\tz1.append(j)\\n\\t\\t\\tif z > 2:\\n\\t\\t\\t\\tbreak\\n\\tif z == 2 and s[z1[0]] == s[z1[1]] and (t[z1[0]] == t[z1[1]]):\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\ts = s1 + s2\\n\\tcount = 0\\n\\td1 = []\\n\\td2 = []\\n\\tfor j in range(n):\\n\\t\\tif s1[j] != s2[j]:\\n\\t\\t\\tcount += 1\\n\\t\\t\\td1.append(s1[j])\\n\\t\\t\\td2.append(s2[j])\\n\\t\\tif count > 2:\\n\\t\\t\\tbreak\\n\\tif count == 2:\\n\\t\\tif d1[0] == d1[1] and d2[0] == d2[1]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"def solve():\\n\\tn = int(input())\\n\\ta = input()\\n\\tb = input()\\n\\t(x, y) = ('', '')\\n\\tw = 0\\n\\tflag = 0\\n\\tfor i in range(len(a)):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\tif w == 0:\\n\\t\\t\\t\\tx = a[i]\\n\\t\\t\\t\\ty = b[i]\\n\\t\\t\\t\\tw += 1\\n\\t\\t\\telif w == 1:\\n\\t\\t\\t\\tif x == a[i] and y == b[i]:\\n\\t\\t\\t\\t\\tflag = 2\\n\\t\\t\\t\\t\\tw += 1\\n\\t\\t\\t\\telse:\\n\\t\\t\\t\\t\\tflag = 1\\n\\t\\t\\t\\t\\tbreak\\n\\t\\t\\telse:\\n\\t\\t\\t\\tflag = 1\\n\\t\\t\\t\\tbreak\\n\\tif flag == 1 or w == 1:\\n\\t\\treturn 'No'\\n\\telse:\\n\\t\\treturn 'Yes'\\nfor _ in range(int(input())):\\n\\tprint(solve())\\n\",\n \"t = int(input())\\nfor _ in range(t):\\n\\tn = int(input())\\n\\ts = list(input())\\n\\tt = list(input())\\n\\ta = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] == t[i]:\\n\\t\\t\\tcontinue\\n\\t\\tj = i + 1\\n\\t\\twhile j < n and t[i] != t[j]:\\n\\t\\t\\tj += 1\\n\\t\\tif j < n:\\n\\t\\t\\t(t[j], s[i]) = (s[i], t[j])\\n\\t\\t\\ta.append([i + 1, j + 1])\\n\\t\\t\\tcontinue\\n\\t\\tj = i + 1\\n\\t\\twhile j < n and t[i] != s[j]:\\n\\t\\t\\tj += 1\\n\\t\\tif j < n:\\n\\t\\t\\t(t[i], s[i]) = (s[i], t[i])\\n\\t\\t\\ta.append([i + 1, i + 1])\\n\\t\\t\\t(t[i], s[j]) = (s[j], t[i])\\n\\t\\t\\ta.append([j + 1, i + 1])\\n\\tif s != t:\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\\tprint('Yes')\\n\\tprint(len(a))\\n\\tfor x in a:\\n\\t\\tprint(x[0], x[1])\\n\",\n \"for i in range(int(input())):\\n\\tn = int(input())\\n\\ta = input()\\n\\tb = input()\\n\\tcounter = 0\\n\\t(x, y) = ([], [])\\n\\tfor (i, j) in zip(a, b):\\n\\t\\tif i != j:\\n\\t\\t\\tcounter += 1\\n\\t\\t\\tx.append(i)\\n\\t\\t\\ty.append(j)\\n\\tif len(set(x)) == len(set(y)) == 1 and counter == 2:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"q = int(input())\\nfor _ in range(q):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tb = 0\\n\\tot = False\\n\\tt = 0\\n\\tfor i in range(n):\\n\\t\\tif s1[i] == s2[i]:\\n\\t\\t\\tt += 1\\n\\t\\tif (s1[i] != s2[i]) & (b == 0):\\n\\t\\t\\tb = 1\\n\\t\\t\\tsi1 = s1[i]\\n\\t\\t\\tsi2 = s2[i]\\n\\t\\telif (s1[i] != s2[i]) & (b == 1):\\n\\t\\t\\tif (si1 == s1[i]) & (si2 == s2[i]):\\n\\t\\t\\t\\tot = True\\n\\tif (ot or s1 == s2) and t == n - 2:\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"for i in range(int(input())):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tc = 0\\n\\tq = ''\\n\\tw = ''\\n\\tfor i in range(len(s1)):\\n\\t\\tif s1[i] == s2[i]:\\n\\t\\t\\tcontinue\\n\\t\\telse:\\n\\t\\t\\tc += 1\\n\\tif c != 2:\\n\\t\\tprint('No')\\n\\telse:\\n\\t\\tfor i in range(len(s1)):\\n\\t\\t\\tif s1[i] == s2[i]:\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\telse:\\n\\t\\t\\t\\tq = q + s1[i]\\n\\t\\t\\t\\tw = w + s2[i]\\n\\t\\tif q[0] == q[1] and w[0] == w[1]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\",\n \"o = int(input())\\nfor _ in range(o):\\n\\tn = int(input())\\n\\ts = list(input())\\n\\tt = list(input())\\n\\tx = 0\\n\\ta = []\\n\\tb = []\\n\\tfor i in range(n - 1, -1, -1):\\n\\t\\tif s[i] == t[i]:\\n\\t\\t\\tdel s[i]\\n\\t\\t\\tdel t[i]\\n\\tif len(s) == 0:\\n\\t\\tprint('Yes')\\n\\telif len(s) == 2 and s[0] + t[0] == s[1] + t[1]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"n = int(input())\\nfor i in range(n):\\n\\tk = int(input())\\n\\ta = input()\\n\\tb = input()\\n\\tcount = 0\\n\\tf = []\\n\\tfor i in range(len(a)):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\tcount += 1\\n\\t\\t\\tf.append(i)\\n\\tif len(f) == 0:\\n\\t\\tprint('Yes')\\n\\telif count > 2 or len(f) < 2:\\n\\t\\tprint('No')\\n\\telif a[f[0]] == a[f[1]] and b[f[0]] == b[f[1]]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"for _ in range(int(input())):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tc = 0\\n\\tl = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != t[i]:\\n\\t\\t\\tc += 1\\n\\t\\t\\tl.append(i)\\n\\tif c == 2 or len(l) == 2:\\n\\t\\tf = 0\\n\\t\\tif s[l[0]] == s[l[1]] and t[l[0]] == t[l[1]]:\\n\\t\\t\\tprint('YES')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"t = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\ts = list(input())\\n\\tt = list(input())\\n\\tcount = 0\\n\\tchange = []\\n\\tfor j in range(n):\\n\\t\\tif s[j] != t[j]:\\n\\t\\t\\tchange.append((s[j], t[j]))\\n\\t\\t\\tcount += 1\\n\\tif count != 2:\\n\\t\\tprint('No')\\n\\telif change[0][0] == change[1][0] and change[0][1] == change[1][1]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\tS1 = input()\\n\\tS2 = input()\\n\\ts1 = list(S1)\\n\\ts2 = list(S2)\\n\\tif S1 == S2:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tfor j in range(n):\\n\\t\\t\\tif s1[j] == s2[j]:\\n\\t\\t\\t\\ts1[j] = '0'\\n\\t\\t\\t\\ts2[j] = '0'\\n\\t\\tx = s1.count('0')\\n\\t\\tfor z in range(x):\\n\\t\\t\\ts1.remove('0')\\n\\t\\t\\ts2.remove('0')\\n\\t\\tif len(s1) > 2:\\n\\t\\t\\tprint('No')\\n\\t\\telif len(s1) == 2:\\n\\t\\t\\tif s1[0] == s1[1] and s2[0] == s2[1]:\\n\\t\\t\\t\\tprint('Yes')\\n\\t\\t\\telse:\\n\\t\\t\\t\\tprint('No')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\",\n \"ans = []\\nfor i in [0] * int(input()):\\n\\tl = int(input())\\n\\t(a, b, x, y, mis) = (input(), input(), set(), set(), 0)\\n\\tfor j in range(l):\\n\\t\\tif a[j] != b[j]:\\n\\t\\t\\tx.add(a[j])\\n\\t\\t\\ty.add(b[j])\\n\\t\\t\\tmis += 1\\n\\tans.append('no' if len(x) > 1 or len(y) > 1 or mis != 2 else 'yes')\\nprint('\\\\n'.join(ans))\\n\",\n \"q = int(input())\\nfor i in range(q):\\n\\tn = int(input())\\n\\ts1 = list(input())\\n\\ts2 = list(input())\\n\\ts1n = list()\\n\\ts2n = list()\\n\\tfor i in range(n):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\ts1n.append(s1[i])\\n\\t\\t\\ts2n.append(s2[i])\\n\\tif len(s1n) == len(s2n) == 2 and s1n[0] == s1n[1] and (s2n[0] == s2n[1]) or len(s1n) == len(s2n) == 0:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nfor _ in range(t):\\n\\tn = int(input())\\n\\ts = input()\\n\\ts1 = input()\\n\\tdiff = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] != s1[i]:\\n\\t\\t\\tdiff.append(i)\\n\\tdiff_len = len(diff)\\n\\tif diff_len == 0:\\n\\t\\tprint('YES')\\n\\telif diff_len == 2:\\n\\t\\tif s[diff[0]] == s[diff[1]] and s1[diff[0]] == s1[diff[1]]:\\n\\t\\t\\tprint('YES')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"def replace_symb(n, word1, word2):\\n\\tletter_pairs = list(zip(word1, word2))\\n\\tstack = []\\n\\tcount = 0\\n\\tfor pair in letter_pairs:\\n\\t\\tif pair[0] != pair[1]:\\n\\t\\t\\tcount += 1\\n\\t\\t\\tif pair in stack:\\n\\t\\t\\t\\tstack.remove(pair)\\n\\t\\t\\telse:\\n\\t\\t\\t\\tstack.append(pair)\\n\\tprint('No' if bool(stack) or count > 2 else 'Yes')\\nfor i in range(int(input())):\\n\\treplace_symb(int(input()), input(), input())\\n\",\n \"t = int(input())\\nfor _ in range(t):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\ti = 0\\n\\t(a, b) = ([], [])\\n\\tcount = 0\\n\\twhile i < n and count < 3:\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\ta.append(s1[i])\\n\\t\\t\\tb.append(s2[i])\\n\\t\\t\\tcount += 1\\n\\t\\ti += 1\\n\\tif count == 2:\\n\\t\\tif a[0] == a[1] and b[0] == b[1]:\\n\\t\\t\\tprint('YES')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"N = int(input())\\nfor _ in range(N):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tdiff_s1 = None\\n\\tdiff_s2 = None\\n\\tfor i in range(n):\\n\\t\\tc1 = s1[i]\\n\\t\\tc2 = s2[i]\\n\\t\\tif c1 == c2:\\n\\t\\t\\tcontinue\\n\\t\\telse:\\n\\t\\t\\tif diff_s1:\\n\\t\\t\\t\\tif diff_s1 == c1 and diff_s2 == c2 and (s1[i + 1:] == s2[i + 1:]):\\n\\t\\t\\t\\t\\tprint('Yes')\\n\\t\\t\\t\\telse:\\n\\t\\t\\t\\t\\tprint('No')\\n\\t\\t\\t\\tbreak\\n\\t\\t\\tdiff_s1 = c1\\n\\t\\t\\tdiff_s2 = c2\\n\\telse:\\n\\t\\tif diff_s1 or len(set(s1)) == n:\\n\\t\\t\\tprint('No')\\n\",\n \"for i in range(int(input())):\\n\\tN = int(input())\\n\\tS1 = input()\\n\\tS2 = input()\\n\\tA = list()\\n\\tB = list()\\n\\tA.extend(S1)\\n\\tB.extend(S2)\\n\\tcount = 0\\n\\ta = list()\\n\\tfor (i, j) in zip(A, B):\\n\\t\\tif i != j:\\n\\t\\t\\tcount += 1\\n\\t\\t\\ta.append((i, j))\\n\\t\\tif count > 2:\\n\\t\\t\\tbreak\\n\\tif count == 1 or count > 2:\\n\\t\\tprint('No')\\n\\telif count == 2:\\n\\t\\tif a[0] == a[1]:\\n\\t\\t\\tprint('Yes')\\n\\t\\telse:\\n\\t\\t\\tprint('No')\\n\",\n \"t = int(input())\\n\\ndef equal(s, t):\\n\\ts = [x for x in s]\\n\\tt = [x for x in t]\\n\\tans = []\\n\\tfor i in range(len(s)):\\n\\t\\tfor j in range(i + 1, len(s)):\\n\\t\\t\\tif s[i] == s[j]:\\n\\t\\t\\t\\t(s[j], t[i]) = (t[i], s[j])\\n\\t\\t\\t\\tans.append([j + 1, i + 1])\\n\\t\\t\\t\\tbreak\\n\\t\\t\\tif s[i] == t[j]:\\n\\t\\t\\t\\t(s[j], t[j]) = (t[j], s[j])\\n\\t\\t\\t\\tans += [[j + 1, j + 1]]\\n\\t\\t\\t\\t(s[j], t[i]) = (t[i], s[j])\\n\\t\\t\\t\\tans += [[j + 1, i + 1]]\\n\\t\\t\\t\\tbreak\\n\\tl = len(ans)\\n\\tans = '\\\\n'.join(['%s %s' % (x[0], x[1]) for x in ans])\\n\\tif s == t:\\n\\t\\treturn 'YES\\\\n%s\\\\n%s' % (l, ans)\\n\\telse:\\n\\t\\treturn 'NO'\\nfor i in range(t):\\n\\tl = input()\\n\\tprint(equal(input(), input()))\\n\",\n \"no_of_test_cases = int(input())\\nfor test_cases in range(no_of_test_cases):\\n\\tlength = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tcheck = [[x, y] for (x, y) in zip(s, t) if x != y]\\n\\tanswer = len(check) == 0\\n\\tif len(check) == 2:\\n\\t\\tanswer = check[0] == check[1]\\n\\tprint('Yes' if answer else 'No')\\n\",\n \"t = int(input())\\nfor i in range(t):\\n\\tn = int(input())\\n\\ts1 = input()\\n\\ts2 = input()\\n\\tdiff = 0\\n\\tt1 = ''\\n\\tt2 = ''\\n\\tfor i in range(n):\\n\\t\\tif s1[i] != s2[i]:\\n\\t\\t\\tdiff += 1\\n\\t\\t\\tt1 += s1[i]\\n\\t\\t\\tt2 += s2[i]\\n\\tif diff > 2 or diff == 1:\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\\tif t1[0] == t1[1] and t2[0] == t2[1]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"k = int(input())\\nfor i in range(k):\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\tif s == t:\\n\\t\\tprint('YES')\\n\\t\\tcontinue\\n\\telse:\\n\\t\\tcount = 0\\n\\t\\tdiff = []\\n\\t\\tfor j in range(n):\\n\\t\\t\\tif s[j] != t[j]:\\n\\t\\t\\t\\tcount += 1\\n\\t\\t\\t\\tdiff.append(j)\\n\\t\\tif count == 2:\\n\\t\\t\\tif s[diff[0]] == s[diff[1]] and t[diff[1]] == t[diff[0]]:\\n\\t\\t\\t\\tprint('YES')\\n\\t\\t\\telse:\\n\\t\\t\\t\\tprint('NO')\\n\\t\\telse:\\n\\t\\t\\tprint('NO')\\n\",\n \"q = int(input())\\nwhile q > 0:\\n\\tq = q - 1\\n\\tn = int(input())\\n\\ts = input()\\n\\tt = input()\\n\\ta = [i for i in s]\\n\\tb = [i for i in t]\\n\\taa = []\\n\\tbb = []\\n\\tc = 0\\n\\tfor i in range(n):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\tc += 1\\n\\t\\t\\taa.append(a[i])\\n\\t\\t\\tbb.append(b[i])\\n\\tif c != 2:\\n\\t\\tprint('No')\\n\\telif aa[0] == aa[1] and bb[1] == bb[0]:\\n\\t\\tprint('Yes')\\n\\telse:\\n\\t\\tprint('No')\\n\",\n \"t = int(input())\\nfor k in range(t):\\n\\tn = int(input())\\n\\ta = input()\\n\\tb = input()\\n\\tdiff = []\\n\\tfail = 0\\n\\tfor i in range(n):\\n\\t\\tif a[i] != b[i]:\\n\\t\\t\\tif len(diff) >= 2:\\n\\t\\t\\t\\tfail = 1\\n\\t\\t\\t\\tbreak\\n\\t\\t\\tdiff.append([a[i], b[i]])\\n\\tif fail or len(diff) == 1:\\n\\t\\tprint('NO')\\n\\t\\tcontinue\\n\\tif (diff[0][0] == diff[1][0]) & (diff[0][1] == diff[1][1]):\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\",\n \"from sys import stdin, stdout\\nfrom collections import Counter\\n\\ndef upar(ind, ch):\\n\\tfor i in range(ind, n):\\n\\t\\tif s[i] == ch:\\n\\t\\t\\treturn i\\n\\treturn -1\\n\\ndef neeche(ind, ch):\\n\\tfor i in range(ind, n):\\n\\t\\tif s1[i] == ch:\\n\\t\\t\\treturn i\\n\\treturn -1\\nfor _ in range(int(stdin.readline())):\\n\\tn = int(stdin.readline())\\n\\ts = list(input())\\n\\ts1 = list(input())\\n\\td = Counter(s)\\n\\tf = 1\\n\\td1 = Counter(s1)\\n\\tfor asc in range(97, 123):\\n\\t\\tch = chr(asc)\\n\\t\\tif d.get(ch, 0) + d1.get(ch, 0) & 1:\\n\\t\\t\\tf = 0\\n\\t\\t\\tbreak\\n\\tif f == 0:\\n\\t\\tprint('No')\\n\\t\\tcontinue\\n\\tl = []\\n\\tfor i in range(n):\\n\\t\\tif s[i] == s1[i]:\\n\\t\\t\\tcontinue\\n\\t\\tp = upar(i + 1, s[i])\\n\\t\\tif p != -1:\\n\\t\\t\\tl += [[p + 1, i + 1]]\\n\\t\\t\\t(s[p], s1[i]) = (s1[i], s[p])\\n\\t\\t\\tcontinue\\n\\t\\tp = neeche(i + 1, s1[i])\\n\\t\\tif p != -1:\\n\\t\\t\\tl += [[i + 1, p + 1]]\\n\\t\\t\\t(s[i], s1[p]) = (s1[p], s[i])\\n\\t\\t\\tcontinue\\n\\t\\tl += [[i + 1, i + 1]]\\n\\t\\t(s[i], s1[i]) = (s1[i], s[i])\\n\\t\\tp = upar(i + 1, s[i])\\n\\t\\tl += [[p + 1, i + 1]]\\n\\t\\t(s[p], s1[i]) = (s1[i], s[p])\\n\\tprint('Yes')\\n\\tprint(len(l))\\n\\tfor (k, v) in l:\\n\\t\\tprint(k, v)\\n\"\n]","isConversational":false},"starter_code":{"kind":"string","value":""},"input_output":{"kind":"string","value":"{\"inputs\": [\"4\\n5\\nsouse\\nhouhe\\n3\\ncat\\ndog\\n2\\naa\\naz\\n3\\nabc\\nbca\\n\", \"10\\n11\\nartiovnldnp\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\nza\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\nix\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nab\\ncd\\n\", \"1\\n4\\naacd\\nbbdc\\n\", \"1\\n4\\naabb\\ncccc\\n\", \"1\\n2\\nab\\ncc\\n\", \"10\\n11\\nartiovnldnp\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\nza\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\nix\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nab\\ncc\\n\", \"1\\n4\\naacd\\nbbdc\\n\", \"1\\n2\\nab\\ncd\\n\", \"1\\n4\\naabb\\ncccc\\n\", \"10\\n11\\nartiovnldnp\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\nza\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nba\\ncc\\n\", \"10\\n11\\npndlnvoitra\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\nza\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"10\\n11\\npndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\naa\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdtfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"4\\n5\\nsouse\\niouhe\\n3\\ncat\\ndog\\n2\\naa\\naz\\n3\\nabc\\nbca\\n\", \"10\\n11\\nartiovnldnp\\nartiovsldsp\\n2\\naa\\nzy\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\nza\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n4\\naadc\\nbbdc\\n\", \"4\\n5\\nsouse\\nhouhe\\n3\\ncat\\ndgo\\n2\\naa\\naz\\n3\\nabc\\nbca\\n\", \"1\\n4\\naadd\\nbbdc\\n\", \"1\\n3\\naabb\\ncccc\\n\", \"1\\n2\\nba\\ncb\\n\", \"1\\n4\\ndaca\\nbbdc\\n\", \"10\\n11\\npndlnvoitra\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nab\\ncb\\n\", \"1\\n1\\ndaca\\nbbdc\\n\", \"10\\n11\\npndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\naa\\ncb\\n\", \"1\\n1\\ndaca\\nbbec\\n\", \"10\\n11\\npndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\naa\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\ndaca\\nbbec\\n\", \"1\\n2\\nacad\\nbbec\\n\", \"10\\n11\\npndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\naa\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdtfkajf\\n2\\nwi\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nacad\\nbbed\\n\", \"10\\n11\\npndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n1\\naa\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdtfkajf\\n2\\nwi\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nacae\\nbbed\\n\", \"1\\n2\\nacaf\\nbbed\\n\", \"10\\n11\\nartiovnldnp\\naruiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\nza\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\nix\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nab\\nbc\\n\", \"1\\n4\\nadca\\nbbdc\\n\", \"1\\n2\\nba\\ncd\\n\", \"1\\n1\\nba\\ncc\\n\", \"1\\n3\\naabb\\ncbcc\\n\", \"10\\n11\\npndlnvoitra\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\nza\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npq\\npa\\n\", \"10\\n11\\npndlnvoitra\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\naz\\nzz\\n3\\nabc\\nacb\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\naa\\nbc\\n\", \"1\\n1\\ndaba\\nbbec\\n\", \"1\\n3\\ndaca\\nbbec\\n\", \"1\\n1\\nacad\\nbbec\\n\", \"10\\n11\\npndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\naa\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdtfkajf\\n2\\nwi\\nhi\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n2\\nacae\\ndbeb\\n\", \"1\\n4\\nacda\\nbbdc\\n\", \"1\\n1\\nba\\ncd\\n\", \"1\\n1\\nab\\ncc\\n\", \"1\\n2\\naa\\nac\\n\", \"1\\n1\\ndbca\\nbbec\\n\", \"1\\n3\\ndbca\\nbbec\\n\", \"1\\n1\\nadad\\nbbec\\n\", \"1\\n2\\neaca\\ndbeb\\n\", \"1\\n4\\ndcaa\\nbbdc\\n\", \"1\\n1\\nbb\\ncd\\n\", \"1\\n2\\ndbca\\nbbec\\n\", \"1\\n3\\ncbca\\nbbec\\n\", \"1\\n2\\nadad\\nbbec\\n\", \"1\\n2\\nacae\\nebeb\\n\", \"1\\n4\\ndcaa\\nbdbc\\n\", \"1\\n3\\ndcba\\nbbec\\n\", \"1\\n3\\nccca\\nbbec\\n\", \"1\\n2\\nadac\\nbbec\\n\", \"1\\n4\\nddaa\\nbdbc\\n\", \"1\\n3\\ndbca\\nebbc\\n\", \"1\\n3\\nccca\\nbaec\\n\", \"1\\n2\\nadac\\nbbce\\n\", \"1\\n4\\nddaa\\nbcbd\\n\", \"1\\n2\\ncada\\nbbce\\n\", \"1\\n2\\ncdaa\\nbbce\\n\", \"1\\n4\\ncdaa\\nbbce\\n\", \"1\\n1\\ncdaa\\nbbce\\n\", \"1\\n2\\naa\\ncc\\n\", \"1\\n3\\naacd\\nbbdc\\n\", \"1\\n2\\nab\\ndc\\n\", \"1\\n4\\naaba\\ncccc\\n\", \"1\\n4\\naadd\\nbdbc\\n\", \"1\\n4\\naabb\\ncccb\\n\", \"1\\n1\\nba\\ncb\\n\", \"1\\n4\\ndbca\\nbbdc\\n\", \"10\\n11\\npndlnvoitra\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\nbajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n1\\nacad\\nbbdc\\n\", \"10\\n11\\npndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\nab\\naa\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdsfkajf\\n2\\niw\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"1\\n1\\ndaca\\ncebb\\n\", \"1\\n4\\nacad\\nbbec\\n\", \"1\\n2\\nacad\\nbbdc\\n\", \"10\\n11\\nqndrnvoitla\\nartiovsldsp\\n2\\naa\\nzz\\n2\\naa\\nxy\\n2\\naa\\nba\\n2\\naz\\nzz\\n3\\nabc\\nbca\\n16\\naajjhdsjfdsfkadf\\naajjhjsjfdtfkajf\\n2\\nwi\\nii\\n2\\noo\\nqo\\n2\\npp\\npa\\n\", \"4\\n5\\nsouse\\nhouhe\\n3\\ncat\\ndog\\n2\\naa\\naz\\n3\\nabc\\nbca\\n\"], \"outputs\": [\"Yes\\nNo\\nNo\\nNo\\n\", \"Yes\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"Yes\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"Yes\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\n\", \"No\\nNo\\nNo\\nNo\\n\", \"Yes\\nNo\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"Yes\\n\", \"Yes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"Yes\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nYes\\nNo\\nNo\\nNo\\n\", \"No\\n\", \"No\\n\", \"No\\n\", \"No\\nYes\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\nNo\\n\", \"Yes\\nNo\\nNo\\nNo\\n\"]}"},"difficulty":{"kind":"string","value":"EASY"},"raw_tags":{"kind":"string","value":"['strings']"},"name":{"kind":"null"},"source":{"kind":"string","value":"codeforces"},"tags":{"kind":"string","value":"['String algorithms']"},"skill_types":{"kind":"string","value":"[]"},"url":{"kind":"string","value":"https://codeforces.com/problemset/problem/1243/B1"},"time_limit":{"kind":"null"},"date":{"kind":"string","value":"2019-12-31"},"picture_num":{"kind":"null"},"memory_limit":{"kind":"null"},"Expected Time Complexity":{"kind":"null"},"task_id":{"kind":"number","value":25408,"string":"25,408"},"solution_id":{"kind":"number","value":0,"string":"0"},"solution":{"kind":"string","value":"t = int(input())\nfor x in range(t):\n\tn = int(input())\n\ts = input()\n\tt = input()\n\ti = c = 0\n\ta = b = ''\n\twhile c < 4 and i < n:\n\t\tif s[i] != t[i]:\n\t\t\tc += 1\n\t\t\ta += s[i]\n\t\t\tb += t[i]\n\t\ti += 1\n\tif c == 2 and len(set(a)) == len(set(b)) == 1:\n\t\tprint('Yes')\n\telse:\n\t\tprint('No')\n"},"text":{"kind":"string","value":"# Question\n\nThis problem is different from the hard version. In this version Ujan makes exactly one exchange. You can hack this problem only if you solve both problems.\n\nAfter struggling and failing many times, Ujan decided to try to clean up his house again. He decided to get his strings in order first.\n\nUjan has two distinct strings $s$ and $t$ of length $n$ consisting of only of lowercase English characters. He wants to make them equal. Since Ujan is lazy, he will perform the following operation exactly once: he takes two positions $i$ and $j$ ($1 \\le i,j \\le n$, the values $i$ and $j$ can be equal or different), and swaps the characters $s_i$ and $t_j$. Can he succeed?\n\nNote that he has to perform this operation exactly once. He has to perform this operation.\n\n\n-----Input-----\n\nThe first line contains a single integer $k$ ($1 \\leq k \\leq 10$), the number of test cases.\n\nFor each of the test cases, the first line contains a single integer $n$ ($2 \\leq n \\leq 10^4$), the length of the strings $s$ and $t$. \n\nEach of the next two lines contains the strings $s$ and $t$, each having length exactly $n$. The strings consist only of lowercase English letters. It is guaranteed that strings are different.\n\n\n-----Output-----\n\nFor each test case, output \"Yes\" if Ujan can make the two strings equal and \"No\" otherwise.\n\nYou can print each letter in any case (upper or lower).\n\n\n-----Example-----\nInput\n4\n5\nsouse\nhouhe\n3\ncat\ndog\n2\naa\naz\n3\nabc\nbca\n\nOutput\nYes\nNo\nNo\nNo\n\n\n\n-----Note-----\n\nIn the first test case, Ujan can swap characters $s_1$ and $t_4$, obtaining the word \"house\".\n\nIn the second test case, it is not possible to make the strings equal using exactly one swap of $s_i$ and $t_j$.\n\n# Solution\n\n```python\nt = int(input())\nfor x in range(t):\n\tn = int(input())\n\ts = input()\n\tt = input()\n\ti = c = 0\n\ta = b = ''\n\twhile c < 4 and i < n:\n\t\tif s[i] != t[i]:\n\t\t\tc += 1\n\t\t\ta += s[i]\n\t\t\tb += t[i]\n\t\ti += 1\n\tif c == 2 and len(set(a)) == len(set(b)) == 1:\n\t\tprint('Yes')\n\telse:\n\t\tprint('No')\n```"}}},{"rowIdx":19492,"cells":{"question":{"kind":"string","value":"You are given a rectangular board of M × N squares. Also you are given an unlimited number of standard domino pieces of 2 × 1 squares. You are allowed to rotate the pieces. You are asked to place as many dominoes as possible on the board so as to meet the following conditions:\n\n1. Each domino completely covers two squares.\n\n2. No two dominoes overlap.\n\n3. Each domino lies entirely inside the board. It is allowed to touch the edges of the board.\n\nFind the maximum number of dominoes, which can be placed under these restrictions.\n\nInput\n\nIn a single line you are given two integers M and N — board sizes in squares (1 ≤ M ≤ N ≤ 16).\n\nOutput\n\nOutput one number — the maximal number of dominoes, which can be placed.\n\nExamples\n\nInput\n\n2 4\n\n\nOutput\n\n4\n\n\nInput\n\n3 3\n\n\nOutput\n\n4"},"solutions":{"kind":"list like","value":["(M, N) = map(int, input().split())\nd = M * N // 2\nprint(d)\n","a = list(map(int, input().split()))\na = a[1] * a[0]\nprint(a // 2)\n","(M, N) = [int(x) for x in input().split()]\nq = N % 2\nw = N // 2\nif q == 0:\n\ts = w * M\nelse:\n\tc = M // 2\n\ts = c + w * M\nprint(s)\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\tprint(int(n * (m / 2)))\nelse:\n\tprint(int(n * (m // 2) + n // 2))\n","def Domino(m, n):\n\tS = m * n\n\tx = S // 2\n\treturn x\n(m, n) = list(map(int, input().split(' ')))\nprint(Domino(m, n))\n","(a, c) = map(int, input().split(' '))\nprint(a * c // 2)\n","lol = [int(i) for i in input().split()]\na = lol[0]\nb = lol[1]\nprint(a * b // 2)\n","(m, n) = [int(i) for i in input().split(' ')]\nif m % 2 == 0:\n\tprint(int(n * (m / 2)))\nelif n % 2 == 0:\n\tprint(int(m * (n / 2)))\nelse:\n\tprint(int(n * ((m - 1) / 2) + n // 2))\n","from math import trunc\n(M, N) = [int(s) for s in input().split(' ')]\nprint(trunc(M * N / 2))\n","inp = input()\ninp = inp.split(' ')\nnum_squares = int(inp[0]) * int(inp[1])\nprint(int(num_squares / 2))\n","(m, n) = map(int, input().split())\na = max(m, n)\nb = min(m, n)\np = a // 2 * b\nif a % 2 != 0:\n\tp = p + b // 2\nprint(p)\n","x = input().split()\np = int(x[0]) * int(x[1])\nif p % 2 == 0:\n\tprint(p // 2)\nif p % 2 != 0:\n\tprint((p - 1) // 2)\n","(w, h) = input().split()\nw = int(w)\nh = int(h)\nif w % 2 == 0:\n\ttotal = w / 2 * h\nelif h % 2 == 0:\n\ttotal = h / 2 * w\nelse:\n\ttotal = (w - 1) / 2 * h + int(h / 2)\nprint(int(total))\n","arr = input().split()\nprint(int(arr[0]) * int(arr[1]) // 2)\n","(m, n) = map(int, input().split())\nif m % 2 == 0 and n % 2 == 0:\n\tprint(int(m / 2 * (n / 1)))\nelif m % 2 == 0 and n % 2 != 0:\n\tprint(int(m / 2 * n))\nelif m % 2 != 0 and n % 2 == 0:\n\tprint(int(n / 2 * m))\nelif m % 2 != 0 and n % 2 != 0:\n\tprint(int(int(m / 2) * int(n - 1) + int(m / 2) + int(n / 2)))\n","(n, m) = map(int, input().split())\nprint(int(n * m / 2))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\na = m * n\nnumber = int(a / 2)\nprint(number)\n","ip = input()\nargs = ip.split(' ')\nM = int(args[0])\nN = int(args[1])\narea = M * N\nans = 0\noneMax = int(M / 2)\nans = oneMax * N\nif oneMax * 2 < M:\n\tans += int(N / 2)\nprint(ans)\n","(m, n) = map(int, input().split(' '))\ntotal_square = m * n\nif total_square % 2 == 0:\n\tprint(int(total_square / 2))\nelse:\n\tprint(int((total_square - 1) / 2))\n","a = input().split(' ')\nm = int(a[0])\nn = int(a[1])\nprint(int(m * n / 2))\n","(m, n) = map(int, input().split())\n(m, r) = divmod(m, 2)\nprint(m * n + n // 2 * r)\n","lisa = input()\nindex = 0\nfor i in range(len(lisa)):\n\tif lisa[i] == ' ':\n\t\tindex = i\nprint(int(int(lisa[0:index]) * int(lisa[index + 1:len(lisa)]) / 2))\n","(M, N) = [int(i) for i in input().split()]\narea = M * N\nprint(area // 2)\n","line = input()\na = line.split()\nx = int(a[0])\ny = int(a[1])\ns = x * y\nif s % 2 == 0:\n\tprint(int(s / 2))\nelse:\n\tprint(int((s - 1) / 2))\n","import math\n(m, n) = list(map(int, str(input()).split()))\nprint(math.floor(m * n / 2))\n","line = input().split()\nprint(int(line[0]) * int(line[1]) // 2)\n","(m, n) = map(int, input().split())\nh = n * int(m / 2)\nv = 0\nif m % 2 == 1:\n\tv = n / 2\nprint(int(h + v))\n","import sys\ninput = sys.stdin.readline\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef insr():\n\ts = input()\n\treturn list(s[:len(s) - 1])\n\ndef invr():\n\treturn map(int, input().split())\n(n, k) = inlt()\ns = int(k * n / 2)\nprint(s)\n","import math\n(a, b) = map(int, input().split())\nn = a * b // 2\nprint(math.ceil(n))\n","import sys\nONLINE_JUDGE = __debug__\nif ONLINE_JUDGE:\n\tinput = sys.stdin.readline\nelse:\n\tsys.stdin = open('ip.txt', 'r')\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef insr():\n\ts = input()\n\treturn list(s[:len(s) - 1])\n\ndef invr():\n\treturn map(int, input().split())\n(M, N) = invr()\nprint(int(M * N / 2))\n","x = input()\nx = x.split(' ')\ny = int(x[0]) * int(x[1])\nprint(y // 2)\n","t = input().split()\nprint(int(int(t[0]) * int(t[1]) / 2))\n","q = input()\nprint(int(q.split(' ')[0]) * int(q.split(' ')[1]) // 2)\n","line = input().split(' ')\n(a, b) = line\na = int(a)\nb = int(b)\nc = a * b / 2\nc = int(c)\nprint('%d' % c)\n","(w, l) = map(int, input().split())\no = int(w * l / 2)\nprint(o)\n","(a, b) = tuple(map(int, input().split()))\nprint(a * b // 2)\n","from math import floor\n(M, N) = map(int, input().split())\nprint(floor(M * N / 2))\n","def main(inp):\n\tprod = inp[0] * inp[1]\n\tif prod % 2 == 0:\n\t\treturn int(prod / 2)\n\telse:\n\t\treturn int((prod - 1) / 2)\ninp = list(map(int, input().split(' ')))\nprint(main(inp))\n","n = list(map(int, input().split(' ')))\nm = n[1]\nn = n[0]\nprint(m * n // 2)\n","(M, N) = [int(x) for x in input().split()]\nou = int(M * N / 2)\nprint(ou)\n","(a, b) = map(int, input().split())\nif a * b % 2 == 0:\n\tz = a * b / 2\nelif a * b % 2 == 1:\n\tz = (a * b - 1) / 2\nprint(int(z))\n","(a, b) = map(int, input().split())\nm = a * b\nif m % 2 == 0:\n\tprint(int(m / 2))\nelse:\n\tprint(int((m - 1) / 2))\n","import math\n(A, B) = map(int, input().split())\n\ndef C(m, n):\n\tA = m * n\n\treturn math.floor(A / 2)\nprint(C(A, B))\n","def solve():\n\t(n, m) = [int(s) for s in input().split()]\n\tprint(n * m // 2)\nsolve()\n","m = input()\nm = m.split(' ')\nc = int(m.pop(), 10)\nf = int(m.pop(), 10)\nif f % 2 == 0:\n\tprint(int(f * c / 2))\nelse:\n\tprint(int(f * (c - 1) / 2 + f / 2))\n","s = input()\n(n, m) = s.split()\nn = int(n)\nm = int(m)\nif n % 2 == 0 or m % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m * n - 1) / 2))\n","data = input().split()\nM = int(data[0])\nN = int(data[1])\nprint((M - M % 2) * (N - N % 2) // 2 + M % 2 * (N // 2) + N % 2 * (M // 2))\n","mn = input().split(' ')\nm = int(mn[0])\nn = int(mn[1])\nprint(m * n // 2)\n","line = input()\n(m, n) = line.split()\nm = int(m)\nn = int(n)\na = max(m, n)\nb = min(m, n)\nif a % 2 == 0:\n\tans = a * b / 2\nelif b % 2 == 0:\n\tans = (a - 1) * b / 2 + b / 2\nelse:\n\tans = (a - 1) * b / 2 + (b - 1) / 2\nans = int(ans)\nprint(ans)\n","inp = list(map(int, input().split()))\nprint(int(inp[0] * inp[1] / 2))\n","def solve(m, n):\n\tdominoes = 0\n\twhile m > 1:\n\t\tdominoes += n\n\t\tm -= 2\n\tif m > 0:\n\t\tdominoes += n // 2\n\treturn dominoes\nprint(solve(*[int(i) for i in input().split(' ')]))\n","line = input().split()\na = int(line[0])\nb = int(line[1])\nif b % 2 == 0:\n\toutcome = a * (b / 2)\n\tprint(int(outcome))\nelse:\n\tb = b - 1\n\tif a % 2 == 0:\n\t\toutcome = a * (b / 2) + a / 2\n\telse:\n\t\toutcome = a * (b / 2) + (a - 1) / 2\n\tprint(int(outcome))\n","M = input()\nN = M[M.find(' ') + 1:]\nM = int(M[:M.find(' ')])\nN = int(N)\nprint(M * N // 2)\n","print(int.__mul__(*map(int, input().split())) // 2)\n","temp = input()\n(m, n) = temp.split(' ')\nm = int(m)\nn = int(n)\ndomino = 2\nboard = m * n\nprint(int(board / domino))\n","mn = input().split()\nm = int(mn[0])\nn = int(mn[1])\na = m * n\nout = a // 2\nprint(out)\n","(m, n) = map(int, input().split())\na = 2 * 1\nb = m * n\nprint(int(b / a))\n","from math import floor\n(n, m) = list(map(int, input().split()))\nprint(floor(m * n * 0.5))\n","(a, b) = map(int, input().split())\nif a != 0 and b != 0:\n\tprint(a * b // 2)\n","import math\n(m, n) = map(int, input().split())\nproduct = m * n / 2\nprint(math.floor(product))\n","def checker(num):\n\treturn int(int(num[0]) * int(num[1]) / 2)\nprint(checker(input().split()))\n","data = list(map(int, input().split()))\nm = data[0]\nn = data[1]\nif m % 2 == 0:\n\tprint(int(m / 2 * n))\nelse:\n\tprint(int(n / 2 * m))\n","(m, n) = [int(x) for x in input().split()]\nprint(str(int(m * n / 2)))\n","(i, j) = input().split(' ')\ni = int(i)\nj = int(j)\nh = i // 2\nh = h * j\nif i % 2 == 0:\n\tprint(h)\nelse:\n\tm = j // 2\n\tm = m + h\n\tprint(m)\n","inputs = input().split(' ')\nm = int(inputs[0])\nn = int(inputs[1])\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\tprint(int(m * n / 2))\n\texit()\nif n % 2 == 0:\n\tprint(int(m * n / 2))\n\texit()\nprint(int((m * n - 1) / 2))\n","x = input().split()\nfor i in range(len(x)):\n\tx[i] = int(x[i])\ny = x[0] * x[1]\nres = y / 2\nif y % 2 != 0:\n\tres = y // 2\nprint(int(res))\n","import math\ndt = list(map(lambda x: int(x), input().split(' ')))\n(n, m) = (dt[0], dt[1])\nprint(max(math.floor(n / 2 * m / 1), math.floor(n / 1 * m / 2)))\n","import math\ninp = input().split()\nm = int(inp[0])\nn = int(inp[1])\nprint(math.floor(m * n / 2))\n","a = input().split()\n(b, c) = (int(a[0]), int(a[1]))\nif b % 2 and c % 2:\n\tprint(int((b * c - 1) / 2))\nelse:\n\tprint(int(b * c / 2))\n","from math import floor\n(m, n) = input().split()\nm = int(m)\nn = int(n)\nprint(floor(m * n / 2))\n","import math\n(M, N) = input().split()\nanswer = 0\nanswer = int(M) * int(N)\nanswer = math.floor(answer / 2)\nprint(answer)\n","s = input().split(' ')\na = int(int(s[0]) * int(s[1]) / 2)\nprint(a)\n","(M, N) = map(int, input().split())\narea = M * N\nanswer = area // 2\nprint(answer)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nn = M * N\nprint(int(n / 2))\n","(n, m) = map(int, input().split())\nx = n * m\noutput = x // 2\nprint(output)\n","import math\n(row, col) = map(int, input().split())\nsizing = row * col\nif sizing % 2 == 0:\n\tamount = sizing / 2\nelse:\n\tamount = math.floor(sizing / 2)\nprint(int(amount))\n","(M, N) = [int(x) for x in input().split()]\nmult = M * N\nprint(int(mult / 2))\n","[m, n] = list(map(int, input().split(' ')))\nif m == 0 or n == 0:\n\tprint(0)\nif m == 1 and n == 1:\n\tprint(0)\nelse:\n\tprint(m * n // 2)\n","(M, N) = map(int, input().strip().split())\ncnt = 0\nif M >= 2:\n\tcnt += M // 2 * N\n\tif M % 2:\n\t\tif N > 1:\n\t\t\tprint(N // 2 + cnt)\n\t\telse:\n\t\t\tprint(cnt)\n\telse:\n\t\tprint(cnt)\nelif N > 1:\n\tprint(N // 2)\nelse:\n\tprint(0)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nd = 0\nif m % 2 == 0:\n\td = n * (m // 2)\nelif n % 2 == 0:\n\td = m * (n // 2)\nelse:\n\td = n * (m // 2) + n // 2\nprint(d)\n","(m, h) = lst = list(map(int, input().split(' ')))\nprint(m * h // 2)\n","import math\n\ndef main():\n\ti = input().split()\n\tm = int(i[0])\n\tn = int(i[1])\n\tout = math.floor(n * m / 2)\n\tprint(out)\nmain()\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nif N * M % 2 == 0:\n\tprint(int(N * M / 2))\nelse:\n\tprint(int((N * M - 1) / 2))\n","(a, b) = [int(i) for i in input().split()]\nprint(int(a * b / 2))\n","def domino(n):\n\tarea = n[0] * n[1]\n\tif area % 2 == 0:\n\t\treturn int(area / 2)\n\telse:\n\t\treturn int((area - 1) / 2)\nn = list(map(int, input().split(' ')))\nans = domino(n)\nprint(ans)\n","(n, m) = map(lambda x: int(x), input().split())\nans = int(n * m / 2.0)\nprint(ans)\n","f = input().split()\nm = int(f[0])\nn = int(f[1])\nM = m * n\nN = M // 2\nprint(N)\n","li = list(map(int, input().split()))\nm = li[0]\nn = li[1]\nres = int(m * n / 2)\nprint(res)\n","(m, n) = input().split()\ns = int(m) * int(n)\nprint(s // 2)\n","def pomnozi_listu(lista):\n\tiznos = 1\n\tfor x in lista:\n\t\tiznos *= x\n\treturn iznos\nbroj = input()\npovrsina = broj.split()\nfor i in range(0, len(povrsina)):\n\tpovrsina[i] = int(povrsina[i])\nif pomnozi_listu(povrsina) % 2 == 0:\n\tprint(pomnozi_listu(povrsina) // 2)\nelif pomnozi_listu(povrsina) % 2 == 1:\n\tprint((pomnozi_listu(povrsina) - 1) // 2)\n","(m, n) = map(int, input().split())\narea = m * n\ndominoes = area // 2\nprint(dominoes)\n","import sys\n\ndef max_dominos(a, b):\n\tif max(a, b) < 2:\n\t\treturn 0\n\tm = max(a, b)\n\tn = min(a, b)\n\tif m % 2 and n % 2:\n\t\treturn max_dominos(m - 1, n) + max_dominos(n, 1)\n\telse:\n\t\treturn int(n * m / 2)\n\ndef main():\n\tinput = sys.stdin.readline()\n\t(m, n) = map(int, input.split())\n\tprint(max_dominos(m, n))\nmain()\n","board_size = [int(i) for i in input().split()]\nif board_size[0] >= 2:\n\tif board_size[0] % 2 == 0:\n\t\tprint(board_size[0] // 2 * board_size[1])\n\telif board_size[1] % 2 == 0:\n\t\tprint(board_size[1] // 2 * board_size[0])\n\telse:\n\t\tprint(board_size[0] // 2 * board_size[1] + board_size[1] // 2)\nelif board_size[0] == 1 and board_size[1] >= 2:\n\tprint(board_size[1] // 2)\nelse:\n\tprint('0')\n","(m, n) = str(input()).split()\nm = int(m)\nn = int(n)\nif 1 <= m and m <= n and (n <= 16):\n\tprint(int(m * n // 2))\n","n_m = input()\nn_m = n_m.split()\nN = int(n_m[0])\nM = int(n_m[1])\nnumber_of_dominoes = int(N * M / 2)\nprint(number_of_dominoes)\n","(x, y) = map(int, input().strip().split())\nprint(x * y // 2)\n","(M, N) = [int(item) for item in input().split(' ')]\nprint(M * N // 2)\n","l = input().split()\nM = int(l[0])\nN = int(l[1])\nn = int(M * N / 2)\nprint(n)\n","rectangle_size = input().split()\nm = int(rectangle_size[0])\nn = int(rectangle_size[1])\ndominos = m * n // 2\nprint(dominos)\n","(m, n) = input().split()\ntotal_spaces = int(m) * int(n)\nmax_dominoes = int(total_spaces / 2)\nprint(max_dominoes)\n","(m, n) = [int(i) for i in input().split()]\nx = m * n // 2\nprint(x)\n","def dp(m, n):\n\ttileArea = 2 * 1\n\tboardArea = m * n\n\treturn boardArea // tileArea\n(m, n) = map(int, input().split())\nprint(dp(m, n))\n","import math\nlimit = input('').strip()\na = []\ncount = 0\nfor i in range(0, len(limit)):\n\tif limit[i] == ' ':\n\t\ta.append(int(limit[int(count):int(i)]))\n\t\tcount = i + 1\n\telif i == len(limit) - 1:\n\t\ta.append(int(limit[int(count):len(limit)]))\none_side = math.floor(a[0] / 2)\nother_side = a[1]\nresult = one_side * other_side + math.floor(a[1] * (a[0] % 2) / 2)\nprint(result)\n","import math\n(m, n) = map(int, input().split(' '))\ns = m * n\nt = math.floor(s / 2)\nprint(t)\n","[M, N] = [int(x) for x in input().split()]\nnmax = 0\nif M == 1:\n\tnmax = N // 2\nif M > 1:\n\ta = M // 2\n\tif N == 1:\n\t\tnmax = a\n\tif N > 1:\n\t\tB0 = M % 2\n\t\tb = N // 2\n\t\tnmax = a * N + b * B0\nprint(nmax)\n","(n, m) = map(int, input().split())\nif m % 2 == 1:\n\tprint(n * (m // 2) + n // 2)\nelse:\n\tprint(n * (m // 2))\n","(n, k) = [int(x) for x in input().split()]\nm = int(n / 2)\ncount = m * k + n % 2 * int(k / 2)\nprint(count)\n","board_dimensions = input('').split()\n(row, col) = board_dimensions\nm = int(row)\nn = int(col)\nlast_col = 0\ndimension_domino = [2, 1]\nif m % 2 == 0:\n\tper_row = m / 2\nelse:\n\tper_row = (m - 1) / 2\n\tif n % 2 == 0:\n\t\tlast_col = n / 2\n\telse:\n\t\tlast_col = (n - 1) / 2\ntotal_dominoes = per_row * n + last_col\nprint(int(total_dominoes))\n","s = input()\nss = s.split(' ')\nlen = float(ss[0]) / 2\nsum = len * float(ss[1])\nprint(int(sum))\n","(m, n) = [int(v) for v in input().split(' ')]\nr = m * n\nif r % 2 == 0:\n\tprint(r // 2)\nelse:\n\tprint((r - 1) // 2)\n","line = input()\nm = int(line.split()[0])\nn = int(line.split()[1])\nprint(m * n // 2)\n","import math\n(m, n) = [int(i) for i in input().split(' ')]\nh = math.floor(m / 2) * n\nif m % 2:\n\th += math.floor(n / 2)\nv = math.floor(n / 2) * m\nif n % 2:\n\tv += math.floor(m / 2)\nprint('%d' % max(v, h))\n","import math\n(M, N) = map(int, input().split())\nA = M * N\nif A % 2 == 0:\n\tprint(int(A / 2))\nelse:\n\tprint(int(math.floor(A / 2)))\n","x = list(map(int, input().split()))\nprint(x[0] * x[1] // 2)\n","ch = input().split()\nn = int(ch[0])\nm = int(ch[1])\nprint(n * m // 2)\n","game_board = input().split()\nX = int(game_board[0])\nY = int(game_board[1])\nboard_size = X * Y\nif board_size % 2 == 0:\n\tans1 = board_size / 2\n\tprint(int(ans1))\nelse:\n\tans2 = (board_size - 1) / 2\n\tprint(int(ans2))\n","import math\n(W, L) = map(int, input().split())\nX = W * L / 2\nout = math.floor(X)\nprint(out)\n","(n, m) = input().split()\n(n, m) = (int(n), int(m))\nc = n * m\nprint(c // 2)\n","(a, b) = map(int, input().split())\nc = a * b\nd = c % 2\nc = c - d\nprint(int(c // 2))\n","(m, n) = [int(elem) for elem in input().split()]\nprint(n * (m // 2) + n // 2 * (m % 2))\n","import sys\n(n, m) = [int(item) for item in sys.stdin.readline().split(' ')]\nif n % 2 == 0:\n\ta = n / 2 * m\nelif m % 2 == 0:\n\ta = m / 2 * n\nelse:\n\ta = n // 2 * m + m // 2\nprint(int(a))\n","(a, b) = list(map(int, input().rstrip().split()))\nprint(a * b // 2)\n","import math\nn = list(map(int, input().split()))\nr = math.floor(n[0] * n[1] / 2)\nprint(r)\n","(m, n) = [int(x) for x in input().split()]\nd = m * n // 2\nprint(d)\n","s = input().split()\n(m, n) = (int(s[0]), int(s[1]))\nprint(m * n // 2)\n","import sys\n(m, n) = sys.stdin.readline().strip().split()\nn = int(n)\nm = int(m)\nif m % 2 == 0 or n % 2 == 0:\n\tresult = m * n / 2\nelse:\n\tresult = (m - 1) * n / 2 + (n - 1) / 2\nresult = int(result)\nprint(result)\n","nums = input().split(' ')\nnums = [int(x) for x in nums]\nres = nums[0] * nums[1]\nif res % 2 == 0:\n\tprint(int(res / 2))\nelse:\n\tprint(int((res - 1) / 2))\n","(m, n) = map(int, input().split())\nif m > n:\n\t(m, n) = (n, m)\ndom = 0\nif m == 1 and n == 1:\n\tprint(0)\nelse:\n\tdom = m * (n // 2)\n\tif n % 2 != 0:\n\t\tdom += m // 2\n\tprint(dom)\n","import math\n(N, M) = [int(x) for x in input().split()]\nd = int(math.floor(N * M / 2))\nprint(d)\n","a = input().split()\nm = int(a[0])\nn = int(a[1])\nboardsize = m * n\ndomino = 2\nmaxdomino = boardsize // domino\nprint(maxdomino)\n","size = [int(i) for i in input().split()]\narea = size[0] * size[1]\nnumb_dominos = int(area / 2)\nprint(numb_dominos)\n","(x, y) = (int(i) for i in input().split())\nprint(int(x * y / 2))\n","(a, b) = tuple((int(x) for x in input().split(' ')))\nt = a * b\nresult = t // 2\nprint(result)\n","MN = input().split(' ')\nM = int(MN[0])\nN = int(MN[1])\nprint(M * N // 2)\n","import sys\n(a, b) = [int(s) for s in input().strip().split()]\nprint(a * b // 2)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nnum = m * n // 2\nprint(num)\n","n = input()\nn = n.split(' ')\nprint(int(n[0]) * int(n[1]) // 2)\n","line = input()\nspieces = line.split()\nm = int(spieces[0])\nn = int(spieces[1])\nif m % 2 != 0 and n % 2 != 0:\n\tt = int((m * n - 1) / 2)\nelse:\n\tt = int(m * n / 2)\nprint(t)\n","(x, y) = map(int, input().split())\narea = x * y\ncounter = int(area / 2)\nprint(counter)\n","import math\ninputs = list(map(lambda x: int(x), input().split()))\nprint(math.floor(inputs[0] * inputs[1] / 2))\n","(m, n) = map(int, input().split())\nx = m / 2\ny = n / 1\nprint(int(x * y))\n","a = [] * 2\na = [int(i) for i in input().split()]\ns = a[0] * a[1]\nprint(s // 2)\n","import sys as s\noutpt = 0\nfor v in s.stdin:\n\tv = v.strip().split()\n\tif len(v) != 2:\n\t\texit(1)\n\telse:\n\t\tprint(int(v[0]) * int(v[1]) // 2)\n\t\texit(0)\nexit(1)\n","(m, n) = list(map(int, input().split()))\narea = m * n\nno = area // 2\nprint(no)\n","ar = [int(n) for n in input().split()]\nprint(ar[0] * ar[1] // 2)\n","(m, n) = input().split()\n(m, n) = (int(m), int(n))\narea = m * n\nprint(area // 2)\n","import time\n\nclass Profiler(object):\n\n\tdef __enter__(self):\n\t\tself._startTime = time.time()\n\n\tdef __exit__(self, type, value, traceback):\n\t\tprint('Elapsed time: {:.3f} sec'.format(time.time() - self._startTime))\n(m, n) = list(map(int, input().split()))\nm2 = m // 2 * 2\nn2 = n // 2 * 2\ncount = m2 * n2 // 2\ncount += (m - m2) * n2 // 2\ncount += (n - n2) * m2 // 2\nprint(count)\n","a = []\na = list(map(int, input().split()))\nl = a[1]\nw = a[0]\nans = 0\nwhile w >= 0:\n\tif w >= 2:\n\t\tans += l\n\telif w == 1:\n\t\tans += l // 2\n\tw = w - 2\nprint(ans)\n","t = input()\nt = list(map(int, t.split()))\nm = t[0]\nn = t[1]\nif m % 2 == 0:\n\td = m // 2 * n\nelif n % 2 == 0:\n\td = n // 2 * m\nelse:\n\td = m // 2 * n + n // 2\nprint(d)\n","str = input().split(' ')\n(M, N) = [int(x) for x in str]\ntotal = M // 2 * N + M % 2 * (N // 2)\nprint(total)\n","import math\nimport os\nimport random\nimport re\nimport sys\n(m, n) = list(map(int, input().split()))\nprint(int(m * n / 2))\n","inp = input()\nM = int(inp.split()[0])\nN = int(inp.split()[1])\ndesk = M * N\ni = desk // 2\nprint(i)\n","p = input()\np2 = p.split()\np1 = [int(p2[i]) for i in range(2)]\nprint(p1[0] * p1[1] // 2)\n","import math\nline = input()\n(n, m) = line.split()\nn = int(n)\nm = int(m)\nresult = math.floor(n * m / 2)\nprint(result)\n","string = [int(x) for x in str(input()).split()]\nprint(int(string[0] * string[1] / 2))\n","line = input().split(' ')\nsize = int(line[0]) * int(line[1])\nprint(int(size / 2) if size > 1 else 0)\n","import math\na = input().split()\nm = int(a[0])\nn = int(a[1])\ns = m * n\nprint(math.floor(s / 2))\n","(x, y) = map(int, input().split())\nz = x * y // 2\nprint(z)\n","F = lambda : map(int, input().split())\n(m, n) = F()\narea = m * n\nif area % 2 == 0:\n\tprint(int(area / 2))\nelse:\n\tprint(int((area - 1) / 2))\n","import math\n(m, n) = map(int, input().split())\narea = m * n\ndomino = 2\nif area % domino == 0:\n\tprint(area // domino)\nelse:\n\tprint(math.floor(area // domino))\n","(k, l) = [int(x) for x in input().split()]\nprint(k * l // 2)\n","(m, n) = map(int, input().split())\nm1 = m // 2 * n + m % 2 * n // 2\nm2 = n // 2 * m + n % 2 * m // 2\nprint(max(m1, m2))\n","(m, n) = input().split()\np = int(m) * int(n)\nprint(p // 2)\n","numbers = input().split(' ')\ncapacity = int(numbers[0]) * int(numbers[1])\nif capacity % 2 == 0:\n\tprint(int(capacity / 2))\nelse:\n\tprint(int((capacity - 1) / 2))\n","(s, r) = input().split()\ng = int(s) * int(r)\nprint(g // 2)\n","(m, n) = map(int, input().split())\ndistance = n * m\nif m <= n and (m >= 1 and m <= 16) and (n <= 16 and n >= 1):\n\tresult = distance // 2\n\tprint(result)\nelse:\n\tprint('exite')\n\tpass\n","(l, m) = map(int, input().split())\nprint(l * m // 2)\n","(n, k) = map(int, input().split())\nif n * k % 2 == 0:\n\tprint(int(n * k / 2))\nelse:\n\tprint(int(n * k) // 2)\n","(M, N) = map(int, input().split())\nif M == 1 and N == 1:\n\tprint(0)\nelse:\n\tprint(M * N // 2)\n","import math\n(r, c) = [int(x) for x in input().split()]\nprint(str(math.floor(r * c * 0.5)))\n","(n, k) = map(int, input().split())\nc = n * k // 2\nprint(c)\n","s = input()\ns = s.split()\nc = 0\nc = int(int(s[1]) / 2) * int(s[0])\nc = c + int(int(s[1]) % 2) * int(int(s[0]) / 2)\nprint(int(c))\n","data = input()\n(m, n) = data.split(' ')\nm = int(m)\nn = int(n)\nsizeOfBoard = m * n\nresult = sizeOfBoard // 2\nprint(result)\n","mn = list(map(int, input().strip().split()))\narea = mn[0] * mn[1]\nresult = int(area / 2)\nprint(result)\n","def domino(n):\n\treturn n // 2\n\ndef main():\n\t(l, L) = map(int, input().split())\n\tprint(domino(l * L))\nmain()\n","(M, N) = list(map(int, input().split()))\nprint(M * N // 2)\n","(w, h) = [int(x) for x in input().split()]\ndominoes = w * h // 2\nprint(dominoes)\n","tab = input()\np = ''\nwhile tab != '':\n\tc = tab[0]\n\tif c in ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']:\n\t\tp = p + c\n\telse:\n\t\tM = int(p)\n\t\tp = ''\n\tif len(tab) > 1:\n\t\ttab = tab[1:]\n\telse:\n\t\ttab = ''\n\t\tN = int(p)\nnum = M * N\ndiv = num // 2\nprint(div)\n","b = input()\nb = b.split()\na = int(b[0])\nb = int(b[1])\na = a * b\nif a % 2 == 0:\n\tprint(int(a / 2))\nelse:\n\tb = a % 2\n\ta = a - b\n\ta = a / 2\n\tprint(int(a))\n","from math import floor\nm = input().split()\nprint(floor(int(m[0]) * int(m[1]) / 2))\n","(x, y) = (int(x) for x in input().split())\nif x * y % 2 == 0:\n\tprint(x * y // 2)\nelse:\n\tprint(x * y // 2)\n","def main():\n\tfrom math import floor\n\t(M, N) = input().split()\n\t(M, N) = (int(M), int(N))\n\tprint(floor(M / 1 * (N / 2)))\nmain()\n","from math import floor\n(A, B) = [int(i) for i in input().split(' ')]\nprint(floor(A * B / 2))\n","(n, k) = input().split()\nprint(int(int(n) * int(k) / 2))\n","import math\n(m, n) = map(int, input().split(' '))\nmap_size = m * n\nprint(math.floor(map_size / 2))\n","import math\n(a, b) = map(int, input().split())\nprint(a * b // 2)\n","(m, n) = map(int, input().split())\nans = m * n // 2\nprint(str(ans))\n","(one, two) = map(int, input().split())\ncheck1 = one * two\nprint(check1 // 2)\n","(m, n) = list(map(int, input().split()))\na = m * n\nprint(a // 2)\n","def solve():\n\t(n, m) = input().split()\n\t(n, m) = (int(n), int(m))\n\treturn int(n * m / 2)\nprint(solve())\n","(a, b) = map(int, input().split())\nif a * b % 9 != 0:\n\tprint(int(a * b / 2))\nelse:\n\tprint(int(a * b // 2))\n","squares = [int(x) for x in input().split()]\nprint(squares[0] * squares[1] // 2)\n","(base, altura) = map(int, input().split())\nprint(base * altura // 2)\n","inp = input().split()\nwidth = int(inp[0])\nheight = int(inp[1])\nif width % 2 == 0 or height % 2 == 0:\n\tdominoes = int(width * height // 2)\nelse:\n\tdominoes = int((width * height - 1) // 2)\nprint(dominoes)\n","a = list(map(int, input().split()))\n(M, N) = (a[0], a[1])\nprint(M * N // 2)\n","import math\n(m, n) = map(int, input().split())\nsum = 0\nif n != 1:\n\tsum = m * math.floor(n / 2)\n\tif n % 2 != 0:\n\t\tsum += math.floor(m / 2)\nprint(sum)\n","(a, b) = map(int, input().split())\nsize = a * b\ndominoes = size // 2\nprint(dominoes)\n","def TotalDominos(m, n):\n\treturn m * n // 2\nvals = input().split()\nm = int(vals[0])\nn = int(vals[1])\nprint(TotalDominos(m, n))\n","texto = input('')\nvalores = texto.split(' ')\nM = int(valores[0])\nN = int(valores[1])\np = M * N\nif p % 2 == 0:\n\tc = p // 2\nelse:\n\tc = (p - 1) // 2\nprint(c)\n","import math\n(X, Y) = map(int, input().split())\np_in_x = X\nrotated_pieces = 0\nif Y % 2 == 0:\n\tp_in_y = int(Y / 2)\nelse:\n\tp_in_y = int(Y / 2)\n\trotated_pieces = int(X / 2)\npieces = p_in_x * p_in_y + rotated_pieces\nprint(int(pieces))\n","lists = list(map(int, input().split(' ')))\nz = int(lists[0] * lists[1] / 2)\nprint(str(z))\n","(r, c) = map(int, input().split())\nprint(r * c // 2)\n","x = str(input())\nM = x[:2]\nN = x[-2:]\nM = int(M)\nN = int(N)\ny = int(M * N / 2)\nprint(y)\n","a = [int(x) for x in input().split()]\nM = a[0]\nN = a[1]\nprod = M * N\nremainder = prod % 2\nif remainder == 0:\n\tprint(int(prod / 2))\nelse:\n\tans = prod - remainder\n\tprint(int(ans / 2))\n","import math as mt\nfrom collections import *\ninf = float('inf')\n\ndef ii():\n\treturn int(input())\n\ndef mii():\n\treturn map(int, input().split())\n\ndef lii():\n\treturn list(map(int, input().split()))\n\ndef gmat(n, m):\n\treturn [[0] * m for _ in range(n)]\n\ndef imat(n):\n\treturn [list(mii()) for _ in range(n)]\n(n, m) = mii()\nprint(mt.floor(n * m * 0.5))\n","def domino_piling(m, n):\n\treturn m * n // 2\n[m, n] = map(int, input().split())\nresult = domino_piling(m, n)\nprint(result)\n","import math\n(m, n) = map(int, input().split())\nif m != 1:\n\tif m % 2 == 1:\n\t\tprint(math.floor(m / 2) * n + n // 2)\n\telse:\n\t\tprint(math.floor(m / 2) * n)\nelif n % 2 == 1:\n\tprint(math.floor(n / 2) * m + m // 2)\nelse:\n\tprint(math.floor(n / 2) * m)\n","import math\n(n, m) = map(int, input().split())\na = math.floor(n * m / 2)\nprint(a)\n","inStr = input()\nm = inStr.split()[0]\nn = inStr.split()[1]\nm = int(m)\nn = int(n)\nprint(m * n // 2)\n","board = input()\nboard_dim = board.split(' ')\nM = int(board_dim[0])\nN = int(board_dim[1])\nprint(M * N // 2)\n","(m, n) = map(int, input().split())\narea = m * n\ndom = area // 2\nprint(dom)\n","g = list(map(int, input().split()))\nif g[0] < 2 and g[1] < 2:\n\tprint('0')\nelse:\n\tprint(int(g[0] * g[1] / 2))\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\na = 2\nb = n * m\nx = b / a\nz = int(x)\nprint(z)\n","(M, N) = input().split()\na = int(int(M) * int(N) / 2)\nprint(a)\n","(M, N) = input().split()\ns = int(M) * int(N)\ns //= 2\nprint(s)\n","n = list(map(int, input().rstrip(' ').split(' ')))\nsize = n[0] * n[1]\nprint(size // 2)\n","(a, b) = map(int, input().split())\nx = a * b / 2\nprint(int(x))\n","(squares_x, squares_y) = map(int, input().split())\nsquares_Sum = squares_x * squares_y\nprint(int(squares_Sum / 2))\n","s = input()\n(m, n) = [int(i) for i in s.split()]\nprint(m * n // 2)\n","def main(m, n):\n\treturn m * n // 2\n(m, n) = map(int, input().split(' '))\nprint(main(m, n))\n","[a, b] = input().split()\nc = int(a) * int(b)\nprint(c // 2)\n","(a, b) = map(int, input().split())\nnum = a * b\nprint(num // 2)\n","import math\n(m, n) = [int(m) for m in input().split()]\nprint(math.floor(m * n / 2))\n","tmp = input().split()\nS = int(tmp[0]) * int(tmp[1])\nprint(S // 2)\n","x = input().split()\nx[0] = int(x[0])\nx[1] = int(x[1])\ns = x[0] * x[1]\nprint(int(s / 2))\n","def main():\n\t(m, n) = get_ints()\n\tresult = m * n // 2\n\tprint(result)\n\ndef get_ints():\n\treturn (int(x) for x in input().split(' '))\nmain()\n","str = input()\nboardSize = [int(s) for s in str.split() if s.isdigit()]\nsurfArea = boardSize[0] * boardSize[1]\ntotal = surfArea / 2\nprint(int(total))\n","board_dimensions = [int(s) for s in input().split(' ')]\narea = board_dimensions[0] * board_dimensions[1]\nprint(int(area / 2))\n","import math\ninp = input()\ninp = inp.split(' ')\nboardSize = float(inp[0]) * float(inp[1])\nans = int(math.floor(boardSize / 2))\nprint(ans)\n","import math\narr = list(map(int, input().split()))\nprint(math.floor(arr[0] * arr[1] / 2))\n","x = input()\nints = [int(s) for s in x.split() if s.isdigit()]\nprint(ints[0] * ints[1] // 2)\n","(m, n) = list(map(int, input().split()))\nd = m * n\nif d % 2 == 0:\n\te = d // 2\n\tprint(e)\nelse:\n\to = (d - 1) // 2\n\tprint(o)\n","(x, y) = [int(x) for x in input().split()]\nk = int(x * y / 2)\nprint(k)\n","from math import floor\n(m, n) = map(int, input().split())\nif m % 2 == 0:\n\tprint(int(m / 2) * n)\nelse:\n\tprint(int(m / 2) * n + int(n / 2))\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nS_mn = n * m\nS_p = 2 * 1\ncount = int(S_mn / S_p)\nprint(count)\n","__author__ = 'runekri3'\n(m, n) = map(int, input().split(' '))\nres = m // 2 * n\nif m % 2:\n\tres += n // 2\nprint(res)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m >= 1 and m <= 16 and (n >= 1) and (n <= 16):\n\tarea = m * n\n\tsize = 2\n\tcount = area // size\nelse:\n\tquit()\nprint(count)\n","(a, b) = map(int, input().split())\nprint(a * b >> 1)\n","entrada = input().split(' ')\nm = int(entrada[0])\nn = int(entrada[1])\nprint(m * n // 2)\n","(n, k) = map(int, input().split())\ns = n * k // 2\nprint(s)\n","(m, n) = map(int, input().strip().split())\nmul = m * n\nif mul == 1:\n\tprint(0)\nelif mul % 2 == 0:\n\tprint(int(mul / 2))\nelse:\n\tprint(int((mul - 1) / 2))\n","import sys\nline = sys.stdin\nline2 = line.readline()\nline3 = line2.split()\na = int(line3[0])\nb = int(line3[1])\narea = int(a * b)\noutput = int(area / 2)\nprint(output)\n","(m, n) = input().strip().split(' ')\n(m, n) = [int(m), int(n)]\nans = m * n // 2\nprint(ans)\n","t = list(map(int, input().split(' ')))\na = t[0]\nb = t[1]\nprint(a * b // 2)\n","(M, N) = map(int, input().split())\nArea = M * N\nRes = Area / 2\nprint(int(Res))\n","(n, m) = input().split()\n\ndef domino(n, m):\n\tif n % 2 == 0 and m % 2 == 0:\n\t\treturn n * m // 2\n\telif n % 2 != 0 and m % 2 == 0:\n\t\treturn m // 2 * n\n\telif m % 2 != 0 and n % 2 == 0:\n\t\treturn n // 2 * m\n\telif n % 2 != 0 and m % 2 != 0:\n\t\treturn n * m // 2\nprint(domino(int(n), int(m)))\n","import sys\nlines = sys.stdin.readlines()\ninput1 = list(map(int, lines[0].split()))\n\ndef size(n, m):\n\tprint(int(n * m / 2))\nsize(input1[0], input1[1])\n","import math\nv = [int(x) for x in input().split(' ')]\nm = v[0]\nn = v[1]\na = max(m, n)\nb = min(m, n)\nc = int(a / 2)\nd = int(b / 2)\nif a % 2 == 0:\n\te = c * b\nelse:\n\te = d + c * b\nprint(e)\n","TN = 1\n\ndef solution():\n\t(m, n) = map(int, input().split())\n\t(m, n) = (min(m, n), max(m, n))\n\tprint(m * n // 2)\nwhile TN != 0:\n\tsolution()\n\tTN -= 1\n","def main():\n\t(n, m) = [int(i) for i in input().split()]\n\tprint(n * m // 2)\nmain()\n","import math\n(n, m) = input().split()\nm = int(m)\nn = int(n)\nm = n * m\nprint('{}'.format(math.floor(m / 2)))\n","from math import floor\n[a, b] = map(int, input().split())\nprint(floor(a * b * (1 / 2)))\n","(x, y) = input().split()\nx = int(x)\ny = int(y)\nif x % 2 == 1 and y % 2 == 1:\n\tans = int((x * y - 1) / 2)\nelse:\n\tans = int(x * y / 2)\nprint(ans)\n","n = input().split()\n(m, n, domino) = (int(n[0]), int(n[1]), 2)\nprint(m * n // domino)\n","(m, n) = [int(x) for x in input().split()]\nif m % 2 == 1 and n % 2 == 1:\n\tresult = int((m * n - 1) / 2)\nelse:\n\tresult = int(m * n / 2)\nprint(result)\n","import sys\nimport math as mt\ninput = sys.stdin.buffer.readline\nt = 1\nfor __ in range(t):\n\t(m, n) = map(int, input().split())\n\tif m % 2 == 0:\n\t\tprint(m // 2 * n)\n\telse:\n\t\tprint((m - 1) // 2 * n + n // 2)\n","(m, n) = [int(i) for i in input().split()]\ni = 0\ns = m * n\nwhile s >= 2:\n\ts -= 2\n\ti += 1\nprint(i)\n","import os\nimport sys\nfrom atexit import register\nfrom io import BytesIO\ninput = lambda : sys.stdin.readline().rstrip('\\r\\n')\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef insr():\n\ts = input()\n\treturn list(s[:len(s) - 1])\n\ndef invr():\n\treturn map(int, input().split())\n(m, n) = invr()\nprint(m // 2 * n + m % 2 * n // 2)\n","[m, n] = [int(i) for i in input().split()]\np = m * n\ncount = 0\nwhile p - 2 >= 0:\n\tcount += 1\n\tp -= 2\nprint(count)\n","line = input()\nline = line.split()\na = int(line[0])\nb = int(line[1])\nif a % 2 == 0 or b % 2 == 0:\n\tprint(int(a * b / 2))\nelif a % 2 != 0 and b % 2 != 0:\n\tprint(int((a * b - 1) / 2))\n","(x, y) = map(int, input().split())\nvolume = x * y\nmaks = volume // 2\nprint(maks)\n","(x, y) = map(int, input().split())\nmul = x * y\nprint(mul // 2)\n","def solve(mn):\n\tmn = mn.split(' ')\n\tarr = []\n\tfor i in mn:\n\t\tarr.append(i)\n\tm = int(arr[0])\n\tn = int(arr[1])\n\tprint(m * n // 2)\nmn = str(input())\nsolve(mn)\n","import math\n(m, n) = map(int, input().split())\nif m % 2 == 0:\n\tmnum = m / 2\n\tans = mnum * n\nelif n % 2 == 0:\n\tnnum = n / 2\n\tans = nnum * m\nelse:\n\tmnum = math.floor(m / 2)\n\tnnum = math.floor(n / 2)\n\tans = mnum * n + nnum\nprint(int(ans))\n","s = input()\nS2 = 2\ns1 = s.split()\nl1 = list(s1)\nl2 = list(map(int, l1))\nS1 = l2[0] * l2[1]\nres = S1 // S2\nprint(res)\n","ip = input().strip().split()\n(M, N) = (int(ip[0]), int(ip[1]))\nprint(M * N // 2)\n","(m, n) = input().split()\nres = int(m) * int(n)\nresult = res // 2\nprint(result)\n","import shlex\na = str(input())\nl = shlex.split(a)\nb = int(l[0]) * int(l[1])\nif b == 1:\n\tprint(0)\nelse:\n\tprint(int(b / 2))\n","(n, k) = map(int, input().split())\nt = n * k // 2\nprint(t)\n","import math\n(n, m) = map(int, input().split())\narea = n * m\nprint(math.floor(area / 2))\n","(m, n) = map(int, input().split())\nc = 0\np = 0\nwhile p < m * n:\n\tp = p + 2\n\tc = c + 1\nif m * n % 2 == 0:\n\tprint(c)\nelse:\n\tprint(c - 1)\n","(a, b) = list(map(int, input().split()))\narea = a * b\nprint(int(area / 2))\n","import math\n(x, y) = map(int, input().split(' '))\nprint(math.floor(x * y / 2))\n","(m, n) = [int(j) for j in input().split()]\nprint(m * n // 2)\n","(m, n) = input().split()\n(m, n) = (int(m), int(n))\nif m % 2 == 0 and n % 2 == 0:\n\ts = m // 2 * n\nelif m % 2 == 1 and n % 2 == 1:\n\ts = m // 2 * n\n\ts += n // 2\nelif m % 2 == 1 and n % 2 == 0:\n\ts = m // 2 * n\n\ts += n // 2\nelse:\n\ta = m\n\tm = n\n\tn = a\n\ts = m // 2 * n\n\ts += n // 2\nprint(s)\n","string = input()\nstring = string.split(' ')\nm = int(string[0])\nn = int(string[1])\nprint(int(m * n / 2))\n","import math\na = [int(i) for i in input().split(' ')]\nn = a[0]\nm = a[1]\nprint(math.floor(n * m / 2))\n","(m, n) = map(int, input().split())\nhe_so = 0\nso_gach = 0\nif n % 2 == 0:\n\the_so = int(n / 2)\n\tso_gach = m * he_so\nelse:\n\the_so = n // 2\n\tso_gach_tam_1 = m * he_so\n\tso_gach_tam_2 = m // 2\n\tso_gach = so_gach_tam_1 + so_gach_tam_2\nprint(so_gach)\n","(rsk, ksk) = [int(i) for i in input().split()]\nprint(int(rsk * ksk / 2))\n","(m, n) = input().split()\narea = int(m) * int(n)\nif area < 2:\n\tprint(0)\nelif area % 2 == 0:\n\tprint(int(area / 2))\nelif area % 2 == 1:\n\tarea -= 1\n\tprint(int(area / 2))\n","(M, N) = [int(x) for x in input().split()]\nar = M * N\nif ar < 2:\n\tprint(0)\nelse:\n\tprint(int(ar / 2))\n","import math\nimport sys\nimport re\n(m, n) = map(int, input().rstrip().split())\na = m * n\nprint(int(a // 2))\n","while True:\n\ttry:\n\t\tline = input()\n\t\tline = line.split()\n\t\t(m, n) = [int(n) for n in line]\n\t\tprint(m * n // 2)\n\texcept EOFError:\n\t\tbreak\n","(m, n) = [int(j) for j in input().split()]\nif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m * n - 1) / 2))\n","l1 = input().split(' ')\nprint(int(int(l1[0]) * int(l1[1]) / 2))\n","line = input()\n(m1, n1) = line.split()\nm = int(m1)\nn = int(n1)\nif m * n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(m * n // 2))\n","import math\nl = list(map(int, input().split()))\n(m, n) = (l[0], l[1])\nprint(math.floor(m * n / 2))\n","def main():\n\t(n, m) = map(int, input().split(' '))\n\ttemp = n * m\n\tprint(temp // 2)\nmain()\n","try:\n\tmn = input()\n\tmn = mn.split()\n\tprint(int(mn[0]) * int(mn[1]) // 2)\nexcept Exception as e:\n\tprint(e)\n","(x, y) = input().split()\nhorizPerRow = int(int(x) / 2)\ntotalHoriz = int(int(y) * horizPerRow)\ntotalVert = 0\nif int(x) % 2 == 1:\n\ttotalVert = int(int(y) / 2)\ntotal = totalHoriz + totalVert\nprint(int(total))\n","(m, n) = [int(x) for x in input().split()]\nif m % 2 == 0 or n % 2 == 0:\n\tprint(m * n // 2)\nelse:\n\tprint(max(m * (n // 2) + m // 2, n * (m // 2) + n // 2))\n","a = list(map(int, input().split()))\nn = a[0]\nm = a[1]\nboard = m * n\nsol = board / 2\nsol = int(sol)\nprint(sol)\n","import math as mt\n(m, n) = [int(x) for x in input().split(' ')]\nprod = m * n\noutput = mt.floor(prod / 2)\nprint(output)\n","import math\n(n, m) = map(int, input().split())\nmax_dominos = m * n / 2\nprint(math.floor(max_dominos))\n","(m, n) = input().split()\n(m, n) = (int(m), int(n))\nk = 0\nif m % 2 != 0 and n % 2 != 0:\n\tk = m - 1\n\tprint(int(k * n / 2 + (n - 1) / 2))\nelse:\n\tprint(int(m * n / 2))\n","(m, n) = map(int, input().split())\nb = int(m * n)\nd = 2\nmax = int(b / d)\nprint(round(max))\n","lst = [int(x) for x in input().split()]\n(m, n) = lst\n\ndef func(m, n):\n\tif n % 2 == 0 or m % 2 == 0:\n\t\tres = m * n / 2\n\telse:\n\t\tres = (m * n - 1) / 2\n\treturn int(res)\nprint(func(m, n))\n","import sys\n(n, m) = map(int, input().split(' '))\nif n == 1 and m % 2 == 0:\n\ty = m // 2\n\tx = int(n // 2 * m)\n\tpass\nelse:\n\tif n % 2 == 0:\n\t\tk = 0\n\t\tpass\n\telse:\n\t\tk = 1\n\tx = int(n // 2 * m)\n\ty = int(m // 2 * k)\nans = int(x + y)\nprint(ans)\n","m = list(map(int, input().split()))\ntotal_area = m[0] * m[1]\nprint(total_area // 2)\n","from sys import stdin\n\ndef main():\n\t(n, k) = map(int, stdin.readline().rstrip().split())\n\tprint(n * k // 2)\nmain()\n","inp = input().split()\nm = int(inp[0])\nn = int(inp[1])\nres = m * n // 2\nprint(res)\n","a = input()\nfor i in range(0, len(a)):\n\twhile a[i] == ' ':\n\t\tfirst = int(a[0:i])\n\t\tsecond = int(a[i + 1:])\n\t\tbreak\ntotal = 0\nif first >= 2 and second >= 1:\n\tif first % 2 == 0:\n\t\ttotal = first / 2 * second\n\telse:\n\t\ttotal = (first - 1) / 2 * second + second / 2 * 1\nif first == 1:\n\ttotal = second / 2 * 1\nprint(int(total))\n","(M, N) = map(int, input().split())\na = 2 * 1\nresult = M * N // a\nprint(result)\n","l = [int(i) for i in input().split()]\nn = l[0]\nm = l[1]\nprint(n * m // 2)\n","import math\n(n, m) = map(float, input().split())\nsBoard = n * m\nnumDomino = math.floor(sBoard / 2)\nprint(numDomino)\n","import math\n(x, y) = input().split()\nm = int(x)\nn = int(y)\no = 0\nif m * n % 2 == 0:\n\to = math.floor(m * n / 2)\nelif m * n % 2 != 0:\n\to = math.floor((m * n - 1) / 2)\nprint(o)\n","try:\n\tl = [int(x) for x in input().split()]\n\tprint(l[0] * l[1] // 2)\nexcept:\n\tpass\n","(x, y) = input().split()\nx = int(x)\ny = int(y)\nprint(x * y // 2)\n","inputs = input()\ninputs = inputs.split()\ns = int(inputs[0]) * int(inputs[1])\nprint(s // 2)\n","import math\nno = input()\n(m, n) = no.split()\nm = int(m)\nn = int(n)\narea = m * n\nans = area / 2\nprint(math.floor(ans))\n","ch = input()\nL = ch.strip().split(' ')\nM = int(L[0])\nN = int(L[1])\nprint(int(N * M / 2))\n","(m, n) = map(int, input().split(' '))\narr = []\nfor i in range(m):\n\tnew = []\n\tfor j in range(n):\n\t\tnew.append(0)\n\tarr.append(new)\nplace_holder = (1, 1)\nfor i in range(len(arr)):\n\tfor j in range(0, len(arr[0]) - 1, 2):\n\t\t(arr[i][j], arr[i][j + 1]) = place_holder\nfor j in range(len(arr[0])):\n\tfor i in range(0, len(arr) - 1, 2):\n\t\tif arr[i][j] == 1:\n\t\t\tcontinue\n\t\telse:\n\t\t\t(arr[i][j], arr[i + 1][j]) = place_holder\ncount = 0\nfor i in range(len(arr)):\n\tfor j in range(len(arr[0])):\n\t\tif arr[i][j] == 1:\n\t\t\tcount += 1\nprint(round(count / 2))\n","lst = input().strip().split(' ')\nn = int(lst[0])\nm = int(lst[1])\nx = n * m\nif x % 2 == 0:\n\tz = x / 2\nelse:\n\tz = (x - 1) / 2\nprint(int(z))\n","import queue\n__read_tokens = queue.Queue()\n\ndef next_string():\n\twhile __read_tokens.empty():\n\t\tfor i in input().split():\n\t\t\t__read_tokens.put(i)\n\treturn __read_tokens.get()\n\ndef next_int():\n\treturn int(next_string())\n\ndef next_float():\n\treturn float(next_string())\n\ndef next_line():\n\tif not __read_tokens.empty():\n\t\traise Exception('Unclean token cache')\n\treturn input()\nn = next_int()\nm = next_int()\nx = (n * m - n * m % 2) // 2\nprint(x)\n","(m, n) = map(int, input().split())\ntotal = m * n\ntotal1 = total // 2\nprint(total1)\n","def solution(m, n):\n\tprint(m * n // 2)\nli = [int(x) for x in input().split()]\nm = li[0]\nn = li[-1]\nsolution(m, n)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nh = 0\nh = b // 2 * a\nif b % 2 == 1 or b == 1:\n\th += a // 2\nprint(h)\n","k = input()\nt = k.split(' ')\n(n, m) = (int(t[0]), int(t[1]))\nif n % 2 == 0 or m % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(((m - 1) * (n - 1) + m + n - 2) / 2))\n","(m, n) = input().split()\nwhile True:\n\ttry:\n\t\tm = int(m)\n\t\tn = int(n)\n\t\tif n <= 16 and m <= n:\n\t\t\tbreak\n\t\telse:\n\t\t\tprint()\n\t\t\t(m, n) = input().split()\n\texcept ValueError:\n\t\tprint: ()\n\t\t(m, n) = input().split()\nmax = m * n / 2\nimport math\nrddownmax = math.floor(max)\nprint(rddownmax)\n","(n, m) = map(int, input().split())\nx = m * n\nif n < 1:\n\tprint(0)\nelif n == 1:\n\tif m <= 1:\n\t\tprint(0)\n\telse:\n\t\tprint(int(x / 2))\nelif m < 1:\n\tprint(0)\nelse:\n\tprint(int(x / 2))\n","(x, y) = map(int, input().split())\nif x * y % 2 == 0:\n\tprint(int(x * y / 2))\nelse:\n\tprint(int((x * y - 1) / 2))\n","(M, N) = map(int, input().split())\n(m, n) = (max(M, N), min(M, N))\nif m % 2 == 1 and n % 2 == 1:\n\tnumber = (m * n - 1) / 2\nelse:\n\tnumber = m * n / 2\nprint(int(number))\n","def sol(m, n):\n\tres = m * n // 2\n\treturn res\n(m, n) = map(int, input().split(' '))\nprint(sol(m, n))\n","domino_area = 2\n\ndef domino():\n\tnums = [int(elem) for elem in input().split()]\n\tprint(nums[0] * nums[1] // domino_area)\ndomino()\n","numbers = input()\ns = numbers.split(' ')\na = int(s[0])\nb = int(s[1])\nprint(int((a * b - a * b % 2) / 2))\n","(n, m) = map(int, input().split())\np = m / 2\nq = n / 1\nprint(int(p * q))\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nA = M * N\nK = A // 2\nprint(K)\n","a = input().split()\n(m, n) = a\nm = int(m)\nn = int(n)\ndominos = m * n // 2\nprint(dominos)\n","import sys\ninput = sys.stdin.readline\n(short_side, long_side) = input().split()\nshort_side = int(short_side)\nlong_side = int(long_side)\nif short_side < 2:\n\tprint(long_side // 2)\n\texit()\nnum_parallels = long_side\nnum_rows = short_side // 2\nextra_blocks = 0\nif short_side % 2 != 0:\n\textra_blocks = long_side // 2\ntotal_blocks = num_parallels * num_rows + extra_blocks\nprint(total_blocks)\n","M_and_N = list(map(int, input().split()))\nS = M_and_N[0] * M_and_N[1]\nnum = S // 2\nprint(num)\n","def domino(m, n):\n\tresult = 0\n\tresult = m * n\n\tif result > 1:\n\t\tif result % 2 == 0:\n\t\t\tresult //= 2\n\t\t\tprint(result)\n\t\telif result % 2 != 0:\n\t\t\tresult = (result - 1) // 2\n\t\t\tprint(result)\n\telse:\n\t\tprint('0')\n(m, n) = (a for a in input().split(' '))\nm = int(m)\nn = int(n)\ndomino(m, n)\n","def board(input):\n\tm = int(input.split(' ')[0])\n\tn = int(input.split(' ')[1])\n\tif m >= 1 and m <= 16 and (n >= 1) and (n <= 16):\n\t\tprint(int(m * n / 2))\n\telse:\n\t\treturn\nboard(input())\n","i = input().split()\nm = int(i[0])\nn = int(i[1])\nprint(m * n // 2)\n","temp = input()\ntemp = temp.split()\nm = int(temp[0])\nn = int(temp[1])\nresult = int(m * n / 2)\nprint(str(result))\n","from math import ceil\n(m, n) = map(int, input().split())\nprint(ceil(m * n) // 2)\n","from math import floor\n(x, y) = input().split()\nx = int(x)\ny = int(y)\nz = x * y\nv = floor(z / 2)\nprint(v)\n","input_data = input()\nlist_we_use = input_data.split(' ')\ne = []\nfor i in list_we_use:\n\te.append(int(i))\nprint(e[0] * e[1] // 2)\n","(v, t) = [int(x) for x in input().split()]\nif v * t % 2 == 0:\n\tprint(int(v * t / 2))\nelse:\n\tprint(int((v * t - 1) / 2))\n","from sys import stdin\n\ndef main():\n\ta = stdin.readline().strip()\n\twhile a != '':\n\t\t(b, c) = a.split()\n\t\t(b, c) = (int(b), int(c))\n\t\td = b * c\n\t\tcont = 0\n\t\twhile d > 1:\n\t\t\tcont += 1\n\t\t\td = d - 2\n\t\tprint(cont)\n\t\ta = stdin.readline().strip()\nmain()\n","(m, n) = [int(i) for i in input().split()]\na = max(n, m)\nb = min(m, n)\nsums = a * (b // 2)\nif b % 2 != 0:\n\tsums = sums + a // 2\nprint(sums)\n","(a, b) = map(int, input().split())\nc = int(a * b)\nd = 2\nmaximum1 = int(c / d)\nprint(round(maximum1))\n","text = input()\nx = text.split(' ')\nresult = int(x[0]) * int(x[1]) / 2\nprint(int(result))\n","(a, b) = list(map(int, input().strip().split(' ')))\nm = max(a, b)\nn = min(a, b)\nres = n // 2\nres1 = m // 2\nif n % 2 != 0 and m % 2 == 0:\n\tans = res * m + res1\nelif n % 2 != 0 and m % 2 != 0:\n\tans = res * m + res1\nelse:\n\tans = res * m\nprint(ans)\n","(m, n) = input().split()\nn = int(n)\nm = int(m)\nz = m * n / 2\nz = int(z)\nprint(z)\n","import math\npieces = input().split()\nm = max(int(pieces[0]), int(pieces[1]))\nn = min(int(pieces[0]), int(pieces[1]))\nif m % 2 == 0:\n\tx = int(m / 2)\n\ty = n\n\ts = x * y\n\tprint(s)\nelif m == 1:\n\tprint(0)\nelse:\n\tx = math.floor(m / 2)\n\ty = math.floor(n / 2)\n\ts = x * n + y\n\tprint(s)\n","k = list(map(int, input().strip().split(' ')))\nprint(k[1] * k[0] // 2)\n","(a, b) = map(int, input().split())\nif a % 2 == 0 or b % 2 == 0:\n\ts = a * b / 2\nelse:\n\ts = (a * b - 1) / 2\ns = int(s)\nprint(s)\n","def rex():\n\ts = input().split(' ')\n\tm = int(s[0])\n\tn = int(s[1])\n\tif m % 2 == 0:\n\t\treturn m * n\n\tif n % 2 == 0:\n\t\treturn m * n\n\treturn m * n - 1\n\treturn max(val1, val2)\nprint(int(rex() / 2))\n","(m, n) = [int(x) for x in input().split()]\ny = m * n // 2\nprint(y)\n","def test_case(m, n):\n\tnum_tiles = m * n\n\tresult = num_tiles // 2\n\tprint(result)\n(m, n) = [int(x) for x in input().split(' ')]\ntest_case(m, n)\n","(m, n) = map(int, input().split())\nprint(m * n >> 1)\n","x = input()\nparts = x.split(' ')\nx = int(parts[0])\ny = int(parts[1])\npieces = 0\nif y >= 2:\n\twhile not y <= 1:\n\t\twhile not x <= 0:\n\t\t\tx -= 1\n\t\t\tpieces += 1\n\t\ty -= 2\n\t\tx = int(parts[0])\nelif x >= 2:\n\twhile not x <= 1:\n\t\tx -= 2\n\t\tpieces += 1\nx = int(parts[0])\nif y == 1:\n\twhile not x <= 1:\n\t\tx -= 2\n\t\tpieces += 1\nprint(pieces)\n","inp = list(map(int, input().split()))\nn = inp[0]\nk = inp[1]\nprint(n * k // 2)\n","import math\nm = input()\nm_n = list(map(int, (x for x in m.split() if x.isdigit())))\nbrd_sz = m_n[0] * m_n[1]\nnum = math.floor(brd_sz / 2)\nprint(num)\n","line = input()\n(m, n) = [int(i) for i in line.split()]\nprint(m * n // 2)\n","(n, m) = list(map(int, input().strip().split()))\nboard_size = n * m\ncheck = 0\nif board_size % 2 == 0:\n\tcheck = board_size * 0.5\nelse:\n\tcheck = board_size * 0.5 - 0.5\nprint(int(check))\n","(a, b) = input().split()\narea = int(a) * int(b)\nnum = area // 2\nprint(num)\n","factors = input()\nfactor_list = factors.split()\narea = int(factor_list[0]) * int(factor_list[1])\nnumber_dominoes = area // 2\nprint(number_dominoes)\n","import math\n(m, n) = [int(x) for x in input().split()]\nif not m % 2:\n\tans = m / 2 * n\nelse:\n\tans = (m - 1) / 2 * n + math.floor(n / 2)\nprint(int(ans))\n","mn = input().split()\narea = int(mn[0]) * int(mn[1])\nprint(area // 2)\n","(M, N) = map(int, input().split())\nmax_count = 0\nmax_count = M * N // 2\nprint(max_count)\n","(a, b) = map(int, input().split())\nc = 0\nif a % 2 == 0:\n\tc = b * (a // 2)\nelse:\n\tc = b * (a // 2) + b // 2\nprint(c)\n","a = input()\n(m, n) = a.split()\nm = int(m)\nn = int(n)\nval = 0\nif m * n % 2 == 0:\n\tval = m * n / 2\nelse:\n\tval = (m * n - 1) / 2\nprint(int(val))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ntemp = m\nwhile True:\n\tif temp % 2 == 0:\n\t\tbreak\n\ttemp -= 1\nrows_left = m - temp\ndom = temp // 2 * n\nif rows_left > 0:\n\tif n % 2 == 0:\n\t\tdom += n // 2\n\telse:\n\t\ttemp1 = n\n\t\twhile True:\n\t\t\tif temp1 % 2 == 0:\n\t\t\t\tbreak\n\t\t\ttemp1 -= 1\n\t\tdom += temp1 // 2\nprint(dom)\n","(M, N) = map(int, input().strip().split())\nif M >= 1 and M <= 16 and (N >= 1) and (N <= 16):\n\tdominoPieces = int(M / 2) * N + M % 2 * int(N / 2)\n\tprint(dominoPieces)\nelse:\n\tquit()\n","(a, b) = list(map(int, input().strip().split(' ')))\nprint(a * b // 2)\n","table = [int(w) for w in input().split()]\nprint(table[0] * table[1] // 2)\n","constraints = list(map(int, input().split()))\nans = int(constraints[1] * constraints[0] * 0.5)\nprint(ans)\n","def main():\n\t(m, n) = [int(x) for x in input().split()]\n\tif n == 1 and m == 1:\n\t\tprint(0)\n\t\treturn\n\tif n % 2 == 0:\n\t\tprint(n // 2 * m)\n\t\treturn\n\tif m % 2 == 0:\n\t\tprint(m // 2 * n)\n\t\treturn\n\tif m < n:\n\t\tt = m\n\t\tm = n\n\t\tn = t\n\tprint(m // 2 * n + n // 2)\n\treturn\nmain()\n","inp = [x for x in input().strip().split(' ')]\n(m, n) = (int(inp[0]), int(inp[1]))\nmult = m * n\nprint((mult - 1) // 2 if mult % 2 == 1 else mult // 2)\n","import math\n[m, n] = input().split()\nM = int(m)\nN = int(n)\nprint(math.floor(M * N / 2))\n","(m, n) = list(map(int, input().split()))\nif m >= 1 and n >= m and (n <= 16):\n\tk = m * n\n\tprint(k // 2)\n","mn1 = str(input())\nmn = mn1.split()\nm = int(mn[0])\nn = int(mn[1])\na = m * n\nprint(a // 2)\n","M = list(map(lambda x: int(x), input().split()))\nprint(M[0] * M[1] // 2)\n","(M, N) = input().split()\nN = int(N)\nM = int(M)\nsquare = N * M\nif 1 <= M <= N <= 16:\n\tprint(square // 2)\n","L = input().split(' ')\nm = int(L[0])\nn = int(L[1])\nif n % 2 == 0:\n\tprint(m * (n // 2))\nelse:\n\tprint(m * n // 2)\n","piece = input().split()\nm = int(piece[0])\nn = int(piece[1])\nanswer = m * n // 2\nprint(answer)\n","(m, n) = map(int, input().split())\na = m * n\nresult = int(a / 2)\nprint(result)\n","mn = list(map(int, input().rstrip().split()))\nm = mn[0]\nn = mn[1]\ncount = m // 2\nif m % 2 == 0:\n\tprint(count * n)\nelse:\n\tprint(count * n + n // 2)\n","(n, m) = [int(value) for value in input().split(' ')]\nprint(int(n * m // 2))\n","(a, b) = input().split(' ')\na = int(a)\nb = int(b)\nx = a * b\ny = x // 2\nprint(y)\n","x = input()\nx = x.split(' ')\nM = int(x[0])\nN = int(x[1])\nprint(int(M * N / 2))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\np = m // 2\nq = n // 2\nif m % 2 == 0:\n\tprint(p * n)\nelif m == 1:\n\tprint(q)\nelif n == 1:\n\tprint(p)\nelse:\n\tprint(p * n + q)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nba = m * n\nif 1 <= m <= 16 and 1 <= n <= 16:\n\tif ba % 2 == 0:\n\t\tprint(int(ba / 2))\n\telif (ba - 1) % 2 == 0:\n\t\tprint(int((ba - 1) / 2))\n","(m, n) = map(int, input().strip().split())\nmul = m * n\nprint(mul // 2)\n","(m, n) = map(int, input().split())\nb = False\nif m % 2 != 0:\n\tb = True\nprint((n * int(m / 2) + int(n / 2) * b, int(n / 2))[m < 2])\n","a = input()\nb = a.split()\ns = int(b[0]) * int(b[1])\nn = s // 2\nprint(n)\n","l = list(map(int, input().split()))\nd = int(l[0] * l[1] / 2)\nprint(d)\n","(q, w) = list(map(int, input().split()))\nprint(q * w // 2)\n","s = input()\nline = list(s.split())\ns1 = int(line[0])\ns2 = int(line[1])\nprint(s1 * s2 // 2)\n","(n, m) = (int(x) for x in input().split())\na = n * m\nprint(a // 2)\n","def main():\n\t(m, n) = input().split()\n\tm = int(m)\n\tn = int(n)\n\tthe_area = m * n\n\tprint(int(the_area / 2))\nmain()\n","(m, n) = [int(x) for x in input().split()]\nnum = m * n / 2\nprint(int(num))\n","import sys\n(length, breadth) = map(int, sys.stdin.readline().split())\nnumbers = 0\nif length >= 2:\n\tnumbers = breadth * (length // 2)\n\tif length % 2 == 1:\n\t\tnumbers = numbers + breadth // 2\nelif breadth >= 2:\n\tnumbers = length * (breadth // 2)\n\tif breadth % 2 == 1:\n\t\tnumbers = numbers + length // 2\nprint(numbers)\n","(l, b) = list(map(int, input().split()))\na = l * b\ndomino = a // 2\nprint(domino)\n","r = input()\nni = r.split()\nm = int(ni[0])\nn = int(ni[1])\nx = int(m * n / (2 * 1))\nprint(x)\n","(m, n) = map(int, input().split())\nif m % 2 == 0 or n % 2 == 0:\n\tans = m * n / 2\nelse:\n\tans = (m * n - 1) / 2\nprint(int(ans))\n","n_m = input()\nlist = n_m.split()\nn = int(list[0])\nm = int(list[1])\nprint(int(n * m / 2))\n","from math import floor\nl = input().split(' ')\nl = [int(i) for i in l]\na = l[0] * l[1]\nprint(floor(a / 2))\n","L = 2\n(M, N) = map(int, input().split())\nluas = M * N\nprint(luas // L)\n","(M, N) = map(int, input().split())\nresult = M * N // 2\nprint(result)\n","(m, n) = [int(x) for x in input().split()]\nareaofboard = m * n\nreminder = areaofboard % 2\nif reminder == 1:\n\tprint(int((areaofboard - 1) / 2))\nelse:\n\tprint(int(areaofboard / 2))\n","(m, n) = [int(c) for c in input().split()]\nsquare = 2\ncount = m * n // square\nprint(count)\n","(a, b) = [int(x) for x in input().split()]\nprint(a * b // 2)\n","(m, n) = map(int, input().split())\nk = m * n\nl = k // 2\nprint(l)\n","data = input()\ndataList = data.split(' ')\nm = int(dataList[0])\nn = int(dataList[1])\nnumber = m * n\nanswer = m * n // 2\nif number % 2 > 0:\n\tanswer = (number - 1) // 2\nprint(answer)\n","from math import floor\nar = input()\nmn = list(map(int, ar.split(' ')))\nprint(int(floor(mn[0] * mn[1] / 2)))\n","[M, N] = [int(i) for i in input().split()]\nt = 0\nt = M * N // 2\nprint(t)\n","(m, n) = [int(x) for x in input().split()]\nif m > 0 and n > 0:\n\tt = m * n // 2\nprint(t)\n","m = input().split()\na = int(m[0])\nb = int(m[1])\nprint(int(a * b / 2))\n","def count_rectagular_square(m, n):\n\treturn m * n\n\ndef count_maximum_dominoes(m, n):\n\trec_square = count_rectagular_square(m, n)\n\tnum = rec_square / 2\n\treturn int(num)\ntry_time = input().strip().split(' ')\ntry_time = [int(i) for i in try_time]\nresult = count_maximum_dominoes(try_time[0], try_time[1])\nprint(result)\n","(n, k) = map(int, input().split())\nyo = n * k\nct = 0\nwhile yo >= 2:\n\tct += 1\n\tyo = yo - 2\nprint(ct)\n","(a, b) = map(int, input().split())\nd = 0\nif a % 2 == 0 or b % 2 == 0:\n\td = a * b / 2\nelse:\n\td = a * b // 2\nprint(round(d))\n","from sys import stdin, stdout\nimport math, sys\nfrom itertools import permutations, combinations\nfrom collections import defaultdict, deque, OrderedDict\nfrom os import path\nimport bisect as bi\nimport heapq\n\ndef yes():\n\tprint('YES')\n\ndef no():\n\tprint('NO')\nif path.exists('input.txt'):\n\tsys.stdin = open('input.txt', 'r')\n\tsys.stdout = open('output.txt', 'w')\n\n\tdef I():\n\t\treturn int(input())\n\n\tdef In():\n\t\treturn map(int, input().split())\nelse:\n\n\tdef I():\n\t\treturn int(stdin.readline())\n\n\tdef In():\n\t\treturn map(int, stdin.readline().split())\n\ndef main():\n\ttry:\n\t\t(n, m) = In()\n\t\tt = n * m // 2\n\t\tprint(t)\n\texcept:\n\t\tpass\nM = 998244353\nP = 1000000007\nfor _ in range(1):\n\tmain()\n","size = input().split()\nM = int(size[0])\nN = int(size[1])\nprint(M * N // 2)\n","def ras(m, n):\n\ta = 1\n\tb = 2\n\tif m % 2 == 0 and n % 2 == 0:\n\t\tx = m * n / 2\n\t\treturn int(x)\n\tif m % 2 != 0 and n % 2 != 0:\n\t\tx = n // 2 * (m / 1) + m // 2\n\t\treturn int(x)\n\tif m % 2 != 0 and n % 2 == 0:\n\t\tx = n / 2 * m\n\t\treturn int(x)\n\tif m % 2 == 0 and n % 2 != 0:\n\t\tx = m / 2 * n\n\t\treturn int(x)\n(m, n) = map(int, input().split())\nr = ras(m, n)\nprint(r)\n","x = list(map(int, input().split()))\na = x[0]\nb = x[1]\nans = 0\nif a % 2 == 0:\n\tans = a * b // 2\nelif b % 2 == 0:\n\tans = a * b // 2\nelse:\n\tans = (a * b - 1) // 2\nprint(ans)\n","(M, N) = [int(a) for a in input().split()]\nprint(M * N // 2)\n","x = [int(y) for y in input().split()]\nprint(x[0] * x[1] // 2)\n","(m, n) = map(int, input().split())\na = m * n\nsolution = a / 2\nsolution = int(solution)\nprint(solution)\n","def domino(n, m):\n\tdomino = 0\n\tfor i in range(n):\n\t\tfor j in range(m):\n\t\t\tdomino += 1\n\tprint(domino // 2)\nn = input()\nn = n.split()\n(n, m) = (int(n[0]), int(n[1]))\ndomino(n, m)\n","from operator import mul\nprint(int(mul(*map(int, input().split())) / 2))\n","(a, b) = map(int, input().split())\nif 1 <= a <= b <= 16:\n\tc = a * b // 2\n\tprint(c)\n","from sys import stdin\nboard = stdin.readline().split()\nboard = list(map(int, board))\nprint(board[0] * board[1] // 2)\n","m_n = list(map(int, input().split()))\nmxn = m_n[0] * m_n[1]\nif mxn % 2 == 0:\n\tprint(int(mxn / 2))\nelse:\n\tprint(int((mxn - 1) / 2))\n","import sys\nimport math\nimport os\nimport itertools\nimport string\nimport heapq\nimport _collections\nfrom collections import Counter\nfrom collections import defaultdict\nfrom functools import lru_cache\nimport bisect\nimport re\nimport queue\nfrom decimal import *\n\nclass Scanner:\n\n\t@staticmethod\n\tdef int():\n\t\treturn int(sys.stdin.readline().rstrip())\n\n\t@staticmethod\n\tdef string():\n\t\treturn sys.stdin.readline().rstrip()\n\n\t@staticmethod\n\tdef map_int():\n\t\treturn [int(x) for x in Scanner.string().split()]\n\n\t@staticmethod\n\tdef string_list(n):\n\t\treturn [input() for i in range(n)]\n\n\t@staticmethod\n\tdef int_list_list(n):\n\t\treturn [Scanner.map_int() for i in range(n)]\n\n\t@staticmethod\n\tdef int_cols_list(n):\n\t\treturn [int(input()) for i in range(n)]\n\nclass Math:\n\n\t@staticmethod\n\tdef gcd(a, b):\n\t\tif b == 0:\n\t\t\treturn a\n\t\treturn Math.gcd(b, a % b)\n\n\t@staticmethod\n\tdef lcm(a, b):\n\t\treturn a * b // Math.gcd(a, b)\n\n\t@staticmethod\n\tdef divisor(n):\n\t\tres = []\n\t\ti = 1\n\t\tfor i in range(1, int(n ** 0.5) + 1):\n\t\t\tif n % i == 0:\n\t\t\t\tres.append(i)\n\t\t\t\tif i != n // i:\n\t\t\t\t\tres.append(n // i)\n\t\treturn res\n\n\t@staticmethod\n\tdef round_up(a, b):\n\t\treturn -(-a // b)\n\n\t@staticmethod\n\tdef is_prime(n):\n\t\tif n < 2:\n\t\t\treturn False\n\t\tif n == 2:\n\t\t\treturn True\n\t\tif n % 2 == 0:\n\t\t\treturn False\n\t\td = int(n ** 0.5) + 1\n\t\tfor i in range(3, d + 1, 2):\n\t\t\tif n % i == 0:\n\t\t\t\treturn False\n\t\treturn True\n\ndef pop_count(x):\n\tx = x - (x >> 1 & 6148914691236517205)\n\tx = (x & 3689348814741910323) + (x >> 2 & 3689348814741910323)\n\tx = x + (x >> 4) & 1085102592571150095\n\tx = x + (x >> 8)\n\tx = x + (x >> 16)\n\tx = x + (x >> 32)\n\treturn x & 127\nMOD = int(1000000000.0) + 7\nINF = int(1000000000000000.0)\n\ndef solve():\n\t(M, N) = Scanner.map_int()\n\tprint(M * N // 2)\n\ndef main():\n\tsolve()\nmain()\n","a = input().split()\nn = int(a[0])\nk = int(a[1])\nc = k * n // 2\nprint(c)\n","import math\n(n, m) = [int(i) for i in input().split()]\nif 0 <= m * n <= 16 ** 16:\n\tprint(math.floor(m * n / 2))\n","x = input()\n(m, n) = x.split(' ')\ny = int(m) * int(n)\nprint(y // 2)\n","x = [int(n) for n in input().split(' ')]\nnum = x[0] * x[1]\nprint(int(num / 2))\n","__author__ = 'myduomilia'\nimport math\n(a, b) = list(map(int, input().split()))\nprint(math.floor(a * b * 0.5))\n","k = input()\ne = k.split(' ')\nj = []\nfor i in e:\n\tj.append(int(i))\nm = j[0] * j[1]\nprint(m // 2)\n","__author__ = 'acer1'\nshuru = input()\npieces = shuru.split()\nchang = int(pieces[0])\nkuan = int(pieces[1])\nif chang // 2 != chang // 2 and kuan // 2 != kuan / 2:\n\tjieguo = (chang * kuan + 1) / 2\nelse:\n\tjieguo = chang * kuan / 2\nprint(int(jieguo))\n","import re\nl = input()\ns = re.split('\\\\s+', l)\nm = int(s[0])\nn = int(s[1])\na = m * n\nsum = a // 2\nprint(sum)\n","w = list(map(int, input().split()))\na = w[0]\nb = w[1]\nc = a * b\nif c % 2 > 0:\n\tc = c - 1\nprint(int(c / 2))\n","x = input()\nz = x.split()\ntable = int(z[0]) * int(z[1])\nresult = int(table / 2)\nprint(result)\n","(n, m) = [int(x) for x in input().split()]\nx = n * m\ny = 2\nz = x // y\nif x >= y:\n\tprint(z)\nelse:\n\tprint(0)\n","(a, b) = map(int, input().split())\nif a % 2 == 0 and b % 2 != 0:\n\tN = a / 2 * b\nelif a % 2 != 0 and b % 2 == 0:\n\tN = b / 2 * a\nelif a % 2 == 0 and b % 2 == 0:\n\tN = a * b / 2\nelse:\n\tN = (a * b - 1) / 2\nprint(str(int(N)))\n","(m, n) = list(map(int, input().split()))\nprint(max(m // 2 * n + m % 2 * n // 2, n // 2 * m + n % 2 * m // 2))\n","m = ['0', '0']\nm = input().split()\nm[0] = int(m[0])\nm[1] = int(m[1])\nif m[0] > 0 and m[1] > 0 and (m[0] < 17) and (m[0] <= m[1]):\n\tprint(m[0] * m[1] // 2)\n","a = input()\na = a.split()\na1 = int(a[0])\na2 = int(a[1])\na3 = a1 * a2\nrespuesta = a3 // 2\nprint(respuesta)\n","(m, n) = map(int, input().split())\nc = m * n\nd = c // 2\nprint(d)\n","import math\ninp = input()\nm = int(inp[0:inp.find(' ')])\nn = int(inp[inp.find(' '):len(inp)])\nif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(n * (m - 1) / 2 + int(n / 2)))\n","[m, n] = list(map(int, input().split()))\nprint(int(0.5 * m * n))\n","(M, N) = [int(i) for i in input().split()]\nn = M * (N // 2)\nif N % 2 != 0:\n\tn += M // 2\nprint(n)\n","while True:\n\t(m, n) = input().split(' ')\n\tif int(m) >= 1 and int(m) <= int(n) and (int(n) <= 16):\n\t\tbreak\nprint(int(m) * int(n) // 2)\n","(M, N) = map(int, input().split())\nsq_user = M * N\nsq_dom = 1 * 2\nprint(int(sq_user // sq_dom))\n","(rows, columns) = map(int, input().split())\ntotal_squares = rows * columns\nmax_dominoes = 0\nwhile total_squares > 1:\n\tmax_dominoes += 1\n\ttotal_squares -= 2\nprint(max_dominoes)\n","(m, n) = [int(x) for x in input().split()]\ntiles = m * n // 2\nprint(tiles)\n","userinput = input()\n(v1, v2) = userinput.split(' ')\nv1 = int(v1)\nv2 = int(v2)\nvalue = 0\nif v1 % 2 == 0 or v2 % 2 == 0:\n\tvalue = v1 * v2 / 2\nelse:\n\tvalue = (v1 - 1) * v2 / 2\n\twhile v1 != 0 and v2 > 2:\n\t\tv2 -= 2\n\t\tvalue = value + 1\nprint(int(value))\n","(M, N) = input().split()\n(M, N) = [int(M), int(N)]\nB = int(M * N / 2)\nprint(B)\n","import sys\n(M, N) = map(int, sys.stdin.readline().split())\nmax_dom = M * N // 2\nsys.stdout.write(str(max_dom))\n","A = input().split()\nM = int(A[0])\nN = int(A[1])\nprint(M * N // 2)\n","import sys\nimport math\nimport array\n(n, m) = map(int, input().split())\nif n % 2 == 0:\n\tprint(int(n * m / 2))\nelif m % 2 == 0:\n\tprint(int(n * m / 2))\nelse:\n\tprint(int((n * m - 1) / 2))\n","k = input()\nb = k.split(' ')\na = []\nfor i in b:\n\ta.append(int(i))\nt = a[0] * a[1]\nprint(t // 2)\n","inpt = list(map(int, input().split()))\nprint(int(inpt[0] * inpt[1] / 2))\n","def main():\n\t(m, n) = list(map(int, input().split()))\n\tdomino = int(2)\n\tboard_size = m * n\n\tboard_size = int(board_size)\n\tif board_size % 2 == 0:\n\t\tprint(int(board_size / domino))\n\telse:\n\t\tboard_size -= 1\n\t\tif board_size == 0:\n\t\t\tprint(0)\n\t\telse:\n\t\t\tprint(int(board_size / domino))\nmain()\n","w = input()\nlista = w.split()\nm = int(lista[0])\nn = int(lista[1])\nif n % 2 == 0:\n\tN = int(n * m / 2)\nelse:\n\tN = int((n - 1) * m / 2 + m / 2)\nprint(N, end='')\n","x = input('')\nx = x.split()\nlenth = int(x[0])\nwidth = int(x[1])\nprint(lenth * width // 2)\n","def count(m, n):\n\tc = 0\n\tc = m // 2 * n\n\tif int(m % 2) == 1:\n\t\tc += n // 2\n\tprint(c)\nmn = input().split()\nm = int(mn[0])\nn = int(mn[1])\ncount(m, n)\n","(M, N) = map(int, input().split())\nif M * N % 2 == 0:\n\tprint('{0:.0f}'.format(M * N / 2))\nelse:\n\tprint(M * N // 2)\n","num = input()\n(m, n) = num.split()\nm = int(m)\nn = int(n)\na = m * n\nd = a // 2\nprint(d)\n","(n, m) = [int(info) for info in input().split(' ')]\nprint(n * m // 2)\n","(n, m) = list(map(int, input().split()))\nr = 0\nif n == 1 or m == 1:\n\tprint(n * m // 2)\nelse:\n\tif n % 2 != 0:\n\t\tn -= 1\n\t\tr = m // 2\n\telif m % 2 != 0:\n\t\tm -= 1\n\t\tr = n // 2\n\tprint(n * m // 2 + r)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ns = 2 * 1\np = m * n // 2\nprint(p)\n","import math\n(m, n) = map(int, input('').split())\nboard_area = m * n\nnum_of_tiles = math.floor(board_area / 2)\nprint(num_of_tiles)\n","(M, N) = map(int, input().split())\nx = M * N // 2\nprint(x)\n","(m, n) = map(int, input().split())\nmt = m * n\nl = mt // 2\nprint(l)\n","x = str(input())\nn = str(x[-2:])\nm = str(x[:2])\nn = int(n)\nm = int(m)\nw = n * m\nd = int(w / 2)\nprint(d)\n","def main(n, m):\n\ti = 1\n\twhile True:\n\t\tif i * 2 <= n * m:\n\t\t\ti += 1\n\t\telse:\n\t\t\tbreak\n\treturn i - 1\nstr = input()\n(n, m) = map(int, str.split(' '))\nans = main(n, m)\nprint(ans)\n","(num1, num2) = map(int, input().split())\nprint(num1 * num2 // 2)\n","(n, k) = map(int, input().split())\na = n * k\nprint(int(a / 2))\n","import math\n(x, y) = map(int, input().split())\nc = math.floor(x / 2)\nr = math.floor(y / 1)\ncount = c * r\nleft = 0\nif x % 2 == 1:\n\tleft = math.floor(y / 2)\nprint(count + left)\n","(m, n) = input().split()\nmul = int(m) * int(n)\nprint(mul // 2)\n","board = list(map(int, input().split()))\nl = board[0]\nw = board[1]\nif l == 1 or w == 1:\n\tans = l * w // 2\nelif l % 2 == 0 and w % 2 == 0:\n\tans = l * w // 2\nelif l * w % 2 == 0:\n\tif l % 2 != 0:\n\t\tans = (l - 1) // 2 * w + w // 2\n\telse:\n\t\tans = (w - 1) // 2 * l + l // 2\nelse:\n\tans = (l - 1) // 2 * (w - 1) + (w - 1) // 2 + (l - 1) // 2\nprint(ans)\n","(m, n) = map(int, input().split())\nx = m * n\nif x % 2 == 0:\n\tprint(int(x / 2))\nelse:\n\tprint(int(x / 2 - 0.5))\n","integers = input().split()\nm = int(integers[0])\nn = int(integers[1])\nans = int(m * n / 2)\nprint(ans)\n","import math\n(a, b) = input().split()\na = int(a)\nb = int(b)\narea = a * b\nappro = math.floor(area / 2)\nprint(int(appro))\n","(m, n) = map(int, input().split())\na = m * n\nt = a\nc = 0\nwhile t >= 2:\n\tt = t - 2\n\tc += 1\nprint(c)\n","m_n = str(input()).split(' ')\nm = int(m_n[0])\nn = int(m_n[1])\nmxn = m * n\nif mxn % 2 == 0:\n\tprint(int(mxn / 2))\nelse:\n\tprint(int((mxn - 1) / 2))\n","line = str(input())\nM = int(line.split()[0])\nN = int(line.split()[1])\nnumber = 0\nif M % 2 == 0:\n\tnumber = N * (M / 2)\nelse:\n\tnumber = N * (M // 2) + N // 2\nprint(int(number))\n","boardSize = []\ntotal = 0\nboardSize = input().split(' ')\nboardSize[0] = int(boardSize[0])\nboardSize[1] = int(boardSize[1])\nunalteredBoard = boardSize[0]\nnewBoard = [1, boardSize[1]]\nif boardSize[0] % 2 == 1:\n\tboardSize[0] -= 1\n\tnewBoard = [1, boardSize[1]]\n\tunalteredBoard = boardSize[0] + 1\n\ttotal += newBoard[1] // 2\nif boardSize[1] % 2 == 1:\n\tboardSize[1] -= 1\n\tnextBoard = [1, unalteredBoard]\n\tif newBoard[1] % 2 == 0:\n\t\tnextBoard = [1, unalteredBoard - 1]\n\ttotal += nextBoard[1] // 2\nsizeOne = boardSize[1] / 2 * boardSize[0]\nsizeTwo = boardSize[0] / 2 * boardSize[1]\ntotal += max([sizeOne, sizeTwo])\nprint(int(total))\n","(m, n) = map(int, input().split())\narea = n * m\no = area / 2\nif area % 2 == 0:\n\tprint(int(o))\nelse:\n\to = area // 2\n\tprint(o)\n","(m, n) = input().split(' ')\nmax = int(m) * int(n) // 2\nprint(max)\n","import math\n(m, n) = map(int, input().split())\nprint(int(m * n / 2) if (m % 2 and n % 2) == 0 else int((m * n - 1) / 2))\n","(m, n) = input().split()\nsquares = int(m) * int(n)\nif squares % 2 == 0:\n\tprint(int(squares / 2))\nelse:\n\tprint(int((squares - 1) / 2))\n","import sys\ninput = sys.stdin.readline\n(m, n) = map(int, input().split())\nprint(m * n // 2)\n","dim = [int(a) for a in input().split()]\nans = 0\nif dim[0] % 2 != 0 and dim[1] % 2 != 0:\n\tans = int(((dim[0] - 1) * dim[1] + (dim[1] - 1)) / 2)\nelse:\n\tans = int(dim[0] * dim[1] / 2)\nprint(ans)\n","input1 = input().split()\nm = int(input1[0])\nn = int(input1[1])\narea = m * n\namount = area // 2\nprint(amount)\n","(a, b) = map(int, input().split())\nd = 0\nd = a * b / 2\nprint(int(d))\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\ta = m * n // 2\nelif n % 2 == 0:\n\ta = m * n // 2\nelse:\n\ta = max(n // 2 * m + m // 2, m // 2 * n + n // 2)\nprint(a)\n","import os\nimport sys\n\ndef get_int():\n\treturn int(input())\n\ndef get_ints():\n\treturn map(int, input().split())\n\ndef get_strs():\n\treturn input().split()\n\ndef get_float():\n\treturn float(input())\n\ndef get_floats():\n\treturn map(float, input().split())\n\ndef list_strs():\n\treturn list(input().split())\n\ndef list_ints():\n\treturn list(map(int, input().split()))\n\ndef list_floats():\n\treturn list(map(float, input.split()))\n\ndef post(x):\n\tprint(x, end=' ')\n(n, m) = get_ints()\nprint(n * m // 2)\n","inp = list(map(int, input().split()))\nM = inp[0]\nN = inp[1]\nprint(M * N // 2)\n","def main():\n\t(m, n) = map(int, input().split(' '))\n\tat = m * n\n\tprint(at // 2)\nmain()\n","(m, n) = map(int, input().split())\nstandard_area = 2 * 1\narea = m * n\nprint(area // standard_area)\n","(M, N) = map(int, input().split())\nA = M * N\na = 2\nprint(A // a)\n","num_list = input().split()\narea = 1\nfor num in num_list:\n\tarea *= int(num)\nprint(area // 2)\n","(n, m) = map(int, input().split())\na1 = m // 2 * n + m % 2 * (n // 2)\na2 = n // 2 * m + n % 2 * (m // 2)\nans = max(a1, a2)\nprint(ans)\n","def isolate(string):\n\tnumlist = []\n\tu = len(string)\n\tj = 0\n\tfor i in range(0, u):\n\t\tcharacter = string[i]\n\t\tif character == ' ':\n\t\t\tpick = int(string[j:i])\n\t\t\tnumlist.append(pick)\n\t\t\tj = i + 1\n\t\telif i == u - 1:\n\t\t\tpick = int(string[j:i + 1])\n\t\t\tnumlist.append(pick)\n\t\t\tj = i + 1\n\treturn numlist\nfr1 = str(input(''))\np = isolate(fr1)\nM = int(p[0])\nN = int(p[1])\nprint(M * N // 2)\n","st = input()\nst = st.split()\nm = st[0]\nn = st[1]\nm = int(m)\nn = int(n)\nif m % 2 == 0:\n\ta = int(n * m / 2)\nelse:\n\tx = (m - 1) / 2\n\ta = int(x * n + n // 2)\nprint(a)\n","(m, n) = map(int, input().split(' '))\np = m * n\ndiv = p // 2\nprint(div)\n","(m, n) = map(int, input().split())\ntot = m * n\nif tot % 2 == 0:\n\tprint(tot // 2)\nelif tot % 2 != 0:\n\tprint(tot // 2)\n","(m, n) = map(int, input().split())\ns = m * n\nd = 2 * 1\na = s // d\nprint(a)\n","inputs = input().split(' ')\nnb_case = int(inputs[0]) * int(inputs[1])\noutputs = nb_case / 2\nprint(int(outputs))\n","(M, N) = [int(i) for i in input().strip().split()]\nprint(M * N // 2)\n","(m, n) = list(map(int, input().split()))\nl = 0\nif n % 2 == 0:\n\tl = n // 2 * m\nelse:\n\tl = n // 2 * m + m // 2\nprint(l)\n","(a, b) = map(int, input().split())\nc = max(a, b)\nd = min(a, b)\nif c % 2 == 0:\n\tprint(int(c / 2 * d))\nelse:\n\tprint(int((c - 1) / 2 * d + d // 2))\n","def domino(n, m):\n\tnumber = 0\n\tif n % 2 == 1 and m % 2 == 1:\n\t\tif n == m == 1:\n\t\t\tnumber = 0\n\t\telse:\n\t\t\tnumber = n * (m // 2) + n // 2\n\telse:\n\t\tnumber = n * m // 2\n\tprint(number)\n(n, m) = map(int, input().split())\ndomino(n, m)\n","himpunan_angka = []\nfor i in range(1, 17):\n\thimpunan_angka.append(i)\nwhile True:\n\tm_dan_n = input().split(' ')\n\tm = int(m_dan_n[0])\n\tn = int(m_dan_n[1])\n\tif m not in himpunan_angka or n not in himpunan_angka or (m <= n) == False:\n\t\tcontinue\n\tbreak\nmn = m * n\nmaks_domino = mn // 2\nprint(maks_domino)\n","sizeInput = input()\nlistInput = sizeInput.split()\nboardSize = int(listInput[0]) * int(listInput[1])\nmaxpossibleDomino = boardSize // 2\nprint(maxpossibleDomino)\n","a = list(map(int, input().split(' ')))\n\ndef intmin(a, b):\n\tprint(a if a < b else b)\nintmin(a[0] // 2 * a[1] + (a[1] // 2 if a[0] % 2 == 1 else 0), a[1] // 2 * a[0] + (a[0] // 2 if a[1] % 2 == 1 else 0))\n","x = input().split()\na = int(x[0])\nb = int(x[1])\nc = a * b\nn = int(c / 2)\nprint(n)\n","in_str = input().split(' ')\nM = int(in_str[0])\nN = int(in_str[1])\nprint(int(M * N / 2))\n","first = input()\nF = [int(x) for x in first.split()]\nprint(F[0] * F[1] // 2)\n","x0 = input()\nx1 = x0.split(' ')\nnew_list = list()\nfor i in x1:\n\tnew_list.append(int(i))\na = int(new_list[0])\nb = int(new_list[1])\nif not a > b:\n\tif a >= 1 and b >= 1 and (a <= 16) and (b <= 16):\n\t\tc = a * b // 2\n\t\tprint(c)\n","(n, m) = map(int, input().split())\nx = m // 1\ny = n // 2\nx1 = m // 1 * n // 2\nx2 = m // 2 * n // 1\nnumber = x1\nif x2 > number:\n\tnumber = x2\nprint(number)\n","(n, m) = map(int, input().split())\nres = n * m\nans = res // 2\nprint(ans)\n","(a, b) = map(int, input().split())\nprint(int((a * b - 1) / 2)) if a % 2 and b % 2 else print(int(a * b / 2))\n","(m, n) = map(int, input().split())\nc = int(m) * int(n)\nr = int(c) / 2\nprint(int(r))\n","N = input()\nn = int(N.split()[0]) * int(N.split()[1])\nif n % 2 == 0:\n\tprint(int(n / 2))\nelse:\n\tprint(int((n - 1) / 2))\n","(a, b) = map(int, input().split())\nif a % 2 == 0:\n\tres = a / 2 * b\nelif b % 2 == 0:\n\tres = b / 2 * a\nelse:\n\tres = int(a / 2) * b + int(b / 2)\nres = int(res)\nprint(res)\n","def domino(m, n):\n\tif m % 2 == 0 or n % 2 == 0:\n\t\treturn n * m / 2\n\telse:\n\t\treturn (m - 1) * (n - 1) / 2 + n // 2 + m // 2\nargs = input().split()\nm = int(args[0])\nn = int(args[1])\nprint(int(domino(m, n)))\n","(lambda y: print(y[0] * y[1] // 2))(list(map(int, input().split())))\n","(M, N) = [int(x) for x in input().split()]\nif 1 <= M <= N <= 16:\n\tK = M * N\nprint(int(K / 2))\n","first_str = input().split(' ')\nm = int(first_str[0])\nn = int(first_str[1])\nboard_area = n * m\ndomino_area = 2\ndomino_num = 0\nif board_area % domino_area != 0:\n\tboard_area -= 1\n\tdomino_num = board_area / domino_area\nelse:\n\tdomino_num = board_area / domino_area\nprint(int(domino_num))\n","import math\n(M, N) = map(int, input().split())\nO = M * N / 2\nP = math.floor(O)\nprint(int(P))\n","input_value = input().split()\nm = int(input_value[0])\nn = int(input_value[1])\ndominos = 0\npom = [[0 for x in range(n)] for y in range(m)]\nif n <= 1 and m <= 1:\n\tdominos = 0\nelse:\n\tif n > 1:\n\t\tfor i in range(m):\n\t\t\tfor o in range(n - 1):\n\t\t\t\tif pom[i][o] == 0 and pom[i][o + 1] == 0:\n\t\t\t\t\tpom[i][o] = 1\n\t\t\t\t\tpom[i][o + 1] = 1\n\t\t\t\t\tdominos += 1\n\tif m > 1:\n\t\tfor i in range(m - 1):\n\t\t\tfor o in range(n):\n\t\t\t\tif pom[i][o] == 0 and pom[i + 1][o] == 0:\n\t\t\t\t\tpom[i][o] = 1\n\t\t\t\t\tpom[i + 1][o] = 1\n\t\t\t\t\tdominos += 1\nprint(dominos)\n","(a, b) = (int(s) for s in input().split())\ns = a * b\nprint(s // 2)\n","(d, m) = input().split()\nprint(int(d) * int(m) // 2)\n","(a, b) = map(int, input().split())\nresult = a * b / 2\nprint(int(result))\n","(m, n) = [int(i) for i in input().split()]\nresult = m * n / 2\nprint(int(result))\n","coords = list(map(int, input().split()))\n(x, y) = (coords[0], coords[1])\nrezult = 0\nrezult += x // 2 * y\nif x % 2 == 1:\n\trezult += y // 2\nprint(rezult)\n","x = input()\ntab = x.split(' ')\nt = int(tab[0]) * int(tab[1])\nres = t / 2\nprint(int(res))\n","(M, N) = map(eval, input().split())\nif M % 2 == 0 or N % 2 == 0:\n\tprint(int(M * N / 2))\nelse:\n\tprint(int(M * N / 2 - 1 / 2))\n","import math\n(M, N) = [int(n) for n in input().split()]\nprint(M * N // 2)\n","i = input().split()\nM = int(i[0])\nN = int(i[1])\narea = M * N\nprint(area // 2)\n","array = input().split()\nlength = int(array[0])\nwidth = int(array[1])\narea = length * width\nanswer = area // 2\nprint(answer)\n","size = input().split(' ')\n(m, n) = (int(size[0]), int(size[1]))\nTwoSide = m // 2\nOneSide = n // 2\nTotalDominos = TwoSide * n\nif m % 2 != 0:\n\tTotalDominos += OneSide\nprint(TotalDominos)\n","m = input()\ns = m.split()\nM = int(s[0])\nN = int(s[1])\nif M * N % 2 == 0:\n\ta = int(M * N / 2)\nelse:\n\ta = int((M * N - 1) / 2)\nprint(a)\n","z = input().split(' ')\nm = int(z[0])\nn = int(z[1])\nprint(m * n // 2)\n","def fun():\n\t(n, m) = map(int, input().split())\n\tprint(n * m // 2)\nfun()\n","def dominos():\n\tm_n = [int(x) for x in input().split()]\n\tsize = m_n[0] * m_n[1]\n\tprint(size // 2)\ndominos()\n","(M, N) = str.split(input())\nM = int(M)\nN = int(N)\nif M % 2 == 0 or N % 2 == 0:\n\tt = M * N / 2\nelse:\n\tt = (M * N - 1) / 2\nprint(int(t))\n","from functools import reduce\nprint(reduce(lambda x, y: x * y, map(int, input().split())) // 2)\n","(m, n) = map(int, input().split())\nx = n / 2\ny = n // 2\nz1 = m * n\nz2 = m * y\nif x == y:\n\tprint(z2)\nelif m < 2:\n\tprint(y)\nelif z1 % 2 == 0:\n\tprint(z1 // 2)\nelse:\n\tw = z1 // 2\n\tprint(w)\n","(m, n) = [int(x) for x in input().split()]\nif m * n % 2 == 0 and 1 <= m <= n <= 16:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(m * n / 2))\n","(w1, w2) = map(int, input().split())\nprint(int(w1 * w2 / 2))\n","do = list(map(int, input().rstrip().split()))\nm = do[0]\nn = do[1]\nans = 0\nprint(int(n * m / 2))\n","ar1 = input().split()\nprint(int(ar1[0]) * int(ar1[1]) // 2)\n","(a, b) = [int(x) for x in input().split()]\nc = a * (b // 2) + b % 2 * (a // 2)\nd = a // 2 * b + a % 2 * (b // 2)\nif c > d:\n\tprint(c)\nelse:\n\tprint(d)\n","x = input().split(' ')\ny = int(x[0]) * int(x[1])\nif y % 2 != 0:\n\ty -= 1\n\tans = y / 2\nelse:\n\tans = y / 2\nprint(int(ans))\n","(length, breadth) = map(int, input().split())\nprint(int(length * breadth / 2))\n","(M, N) = map(int, input().split())\nif M % 2 == 0:\n\ts = M // 2 * N\nelif N % 2 == 0:\n\ts = N // 2 * M\nelse:\n\ts = N // 2 * M + M // 2\nprint(s)\n","(M, N) = [int(x) for x in input().split()]\nk = M * N\nnum = k // 2\nprint(num)\n","(m, n) = map(int, input().split())\ns = m * n\nd = 0\nif s % 2 == 0:\n\td = s / 2\nelse:\n\td = (s - 1) / 2\nprint(int(d))\n","s = input()\ns = s.split()\nn = int(s[0]) * int(s[1])\nresult = n // 2\nprint(result)\n","from sys import stdin, stdout\n(M, N) = map(int, stdin.readline().rstrip().split())\narea = M * N\namount_of_dominos = area // 2\nstdout.write(str(amount_of_dominos))\n","import math\ns = input()\ns = s.split(' ')\n(a, b) = (int(s[0]), int(s[1]))\na = a * b\nprint(math.floor(a / 2))\n","(m, n) = [int(x) for x in input().split()]\nif m * n % 2 == 0:\n\tprint('{0:.0f}'.format(m * n / 2))\nelse:\n\tprint('{0:.0f}'.format((m * n - 1) / 2))\n","def main():\n\t_ = input().split(' ')\n\t(n, m) = [int(i) for i in _]\n\tif n < 1 or m < 1:\n\t\treturn 0\n\tif n == 1 and m == 1:\n\t\treturn 0\n\tif n == 1:\n\t\treturn m // 2\n\tif m == 1:\n\t\treturn n // 2\n\tif n % 2 == 0 or m % 2 == 0:\n\t\treturn n * m // 2\n\telse:\n\t\tresult = (n - 1) * (m - 1) // 2\n\t\tif n > 1 and m > 1:\n\t\t\tresult += (n + m - 1) // 2\n\t\treturn result\n\treturn None\nprint(main())\n","def convert(arr):\n\tarr = arr.split(' ')\n\tfor i in range(len(arr)):\n\t\tarr[i] = int(arr[i])\n\treturn arr\narea = input()\ndim = convert(area)\nprint(int(dim[0] * dim[1] / 2))\n","numbers = [int(x) for x in input().split()]\nsquares = numbers[0] * numbers[1]\nif squares % 2 == 0:\n\tprint(int(squares / 2))\nelse:\n\tprint(int((squares - 1) / 2))\n","from sys import stdin, stdout\nimport bisect\nfrom bisect import bisect_left as bl\nfrom bisect import bisect_right as br\nimport itertools\nfrom collections import Counter\nimport collections\nimport math\nimport heapq\nimport re\n\ndef modinv(n, p):\n\treturn pow(n, p - 2, p)\n\ndef cin():\n\treturn map(int, sin().split())\n\ndef ain():\n\treturn list(map(int, sin().split()))\n\ndef sin():\n\treturn input()\n\ndef inin():\n\treturn int(input())\n\ndef Divisors(n):\n\tl = []\n\tfor i in range(1, int(math.sqrt(n) + 1)):\n\t\tif n % i == 0:\n\t\t\tif n // i == i:\n\t\t\t\tl.append(i)\n\t\t\telse:\n\t\t\t\tl.append(i)\n\t\t\t\tl.append(n // i)\n\treturn l\n\ndef most_frequent(list):\n\treturn max(set(list), key=list.count)\n\ndef GCD(x, y):\n\twhile y:\n\t\t(x, y) = (y, x % y)\n\treturn x\n\ndef ncr(n, r, p):\n\tt = fact[n] * (ifact[r] * ifact[n - r] % p) % p\n\treturn t\n\ndef Convert(string):\n\tli = list(string.split(''))\n\treturn li\n\ndef SieveOfEratosthenes(n):\n\tglobal prime\n\tprime = [True for i in range(n + 1)]\n\tp = 2\n\twhile p * p <= n:\n\t\tif prime[p] == True:\n\t\t\tfor i in range(p * p, n + 1, p):\n\t\t\t\tprime[i] = False\n\t\tp += 1\n\tf = []\n\tfor p in range(2, n):\n\t\tif prime[p]:\n\t\t\tf.append(p)\n\treturn f\nprime = []\nq = []\n\ndef dfs(n, d, v, c):\n\tglobal q\n\tv[n] = 1\n\tx = d[n]\n\tq.append(n)\n\tj = c\n\tfor i in x:\n\t\tif i not in v:\n\t\t\tf = dfs(i, d, v, c + 1)\n\t\t\tj = max(j, f)\n\treturn j\n\ndef main():\n\t(n, m) = map(int, input().split())\n\tif n > m:\n\t\t(n, m) = (m, n)\n\tif n == 1:\n\t\tif m == 1:\n\t\t\tprint(0)\n\t\telse:\n\t\t\tprint(m // 2)\n\telif m % 2 == 0:\n\t\tprint(m // 2 * n)\n\telse:\n\t\tprint(m // 2 * n + n // 2)\npy2 = round(0.5)\nif py2:\n\tfrom future_builtins import ascii, filter, hex, map, oct, zip\n\trange = xrange\nimport os, sys\nfrom io import IOBase, BytesIO\nBUFSIZE = 8192\n\nclass FastIO(BytesIO):\n\tnewlines = 0\n\n\tdef __init__(self, file):\n\t\tself._file = file\n\t\tself._fd = file.fileno()\n\t\tself.writable = 'x' in file.mode or 'w' in file.mode\n\t\tself.write = super(FastIO, self).write if self.writable else None\n\n\tdef _fill(self):\n\t\ts = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))\n\t\tself.seek((self.tell(), self.seek(0, 2), super(FastIO, self).write(s))[0])\n\t\treturn s\n\n\tdef read(self):\n\t\twhile self._fill():\n\t\t\tpass\n\t\treturn super(FastIO, self).read()\n\n\tdef readline(self):\n\t\twhile self.newlines == 0:\n\t\t\ts = self._fill()\n\t\t\tself.newlines = s.count(b'\\n') + (not s)\n\t\tself.newlines -= 1\n\t\treturn super(FastIO, self).readline()\n\n\tdef flush(self):\n\t\tif self.writable:\n\t\t\tos.write(self._fd, self.getvalue())\n\t\t\t(self.truncate(0), self.seek(0))\n\nclass IOWrapper(IOBase):\n\n\tdef __init__(self, file):\n\t\tself.buffer = FastIO(file)\n\t\tself.flush = self.buffer.flush\n\t\tself.writable = self.buffer.writable\n\t\tif py2:\n\t\t\tself.write = self.buffer.write\n\t\t\tself.read = self.buffer.read\n\t\t\tself.readline = self.buffer.readline\n\t\telse:\n\t\t\tself.write = lambda s: self.buffer.write(s.encode('ascii'))\n\t\t\tself.read = lambda : self.buffer.read().decode('ascii')\n\t\t\tself.readline = lambda : self.buffer.readline().decode('ascii')\n(sys.stdin, sys.stdout) = (IOWrapper(sys.stdin), IOWrapper(sys.stdout))\ninput = lambda : sys.stdin.readline().rstrip('\\r\\n')\nmain()\n","square = input()\nsquarelist = square.split()\nrest = int(squarelist[0]) * int(squarelist[1]) % 2\nif int(rest) > 0:\n\toutput = (int(squarelist[0]) * int(squarelist[1]) - 1) / 2\n\tprint(int(output))\nelse:\n\toutput = int(squarelist[0]) * int(squarelist[1]) / 2\n\tprint(int(output))\n","count = 0\nrazmery = input()\nmassiv = razmery.split()\nm = int(massiv[0])\nn = int(massiv[1])\ni = 2 * 1\ns = m * n\nwhile i <= s:\n\tif i <= s:\n\t\tcount += 1\n\t\ti = i + 2\nprint(count)\n","def main():\n\ta = input().split(' ')\n\tm = int(a[0])\n\tn = int(a[1])\n\tprint(m * n // 2)\nmain()\n","L = list(map(int, input().split()))\na = L[0]\nb = int(L[1] / 2)\nif L[1] % 2 == 0:\n\tc = 0\nelse:\n\tc = int(L[0] / 2)\nnum = a * b + c\nprint(int(num))\n","board = input().split()\nboard[0] = int(board[0])\nboard[1] = int(board[1])\ns = board[0] * board[1]\nif s % 2 == 0:\n\tans = s / 2\nelse:\n\tans = (s - 1) / 2\nprint(round(ans))\n","def number_dominoes(M, N):\n\tarea = M * N\n\tif area % 2 == 0:\n\t\treturn area / 2\n\telse:\n\t\treturn (area - 1) / 2\n\ndef main():\n\t(M, N) = input().split()\n\tM = int(M)\n\tN = int(N)\n\tn_d = number_dominoes(M, N)\n\tn_d = int(n_d)\n\tprint(n_d)\nmain()\n","def operation(a, b):\n\tprint(int(a * b / 2))\n(a, b) = map(int, input().split())\noperation(a, b)\n","a = input().split(sep=' ')\nprint(int(a[0]) * int(a[1]) // 2)\n","(p, q) = map(int, input().split())\nprint(p * q // 2)\n","(K, N) = map(int, input().split())\n_M = K * N\n_res = _M // 2\nprint(_res)\n","(m, n) = map(int, input().split())\ntotal = 0\nwhile m > 1 or n > 1:\n\ta = max(m, n)\n\tb = min(m, n)\n\ttotal = total + b\n\tm = a - 2\n\tn = b\nprint(total)\n","(M, N) = list(map(int, input().split()))\nif M % 2 == 0 and N % 2 == 0:\n\tprint(M * N // 2)\nelif M % 2 == 0 and N % 2 != 0 or (M % 2 != 0 and N % 2 == 0):\n\tprint(M * N // 2)\nelif M % 2 != 0 and N % 2 != 0:\n\tif M > N:\n\t\tprint(M * (N - 1) // 2 + (M - 1) // 2)\n\telse:\n\t\tprint(N * (M - 1) // 2 + (N - 1) // 2)\n","ans = 0\n(n, m) = input().split()\nx = int(n) / 2\ny = int(m) / 2\nans = x * int(m)\nif x * 2 < int(n):\n\tans += y\nprint(int(ans))\n","a = [int(i) for i in input().split(' ')]\narea = a[0] * a[1]\nprint(area // 2)\n","(n, m) = tuple(input().split())\nprint(int(n) * int(m) // 2)\n","wer = input()\nlist_we_use = wer.split(' ')\nr = []\nfor i in list_we_use:\n\tr.append(int(i))\nt = r[0] * r[1]\nprint(t // 2)\n","(s, b) = [int(x) for x in input().split()]\nd = max(s, b)\nk = min(s, b)\nl = 0\nif k >= 2:\n\tif k >= 2 and k % 2 == 1:\n\t\tl = d * (k // 2) + d // 2\n\telse:\n\t\tl = d * (k // 2)\nelse:\n\tl = d // 2\nprint(l)\n","numbers = input().split()\na = int(numbers[0])\nb = int(numbers[1])\nm = min(a, b)\nn = max(a, b)\nif m == 0:\n\tprint(0)\nelif m == 1:\n\tprint(n // 2)\nelse:\n\tprint(n * (m // 2) + m % 2 * (n // 2))\n","(m, n) = map(float, input().split())\nan = int(m * n // 2.0)\nprint(an)\n","(x, y) = map(int, input().split())\nif x == 1:\n\tprint(int(y / 2))\nif x % 2 == 0:\n\tprint(int(x / 2 * y))\nelif y == 1 and x != 1:\n\tprint(int((x - 1) / 2 * y))\nelif x != 1:\n\tprint(int((x - 1) / 2 * y + int(y / 2)))\n","(M, N) = map(int, input().split())\nif M * N % 2 == 0:\n\ta = M * N // 2\nelse:\n\ta = M * N // 2\nprint(a)\n","(M, N) = list(map(int, input().split()))\nif 1 <= M <= N <= 16:\n\tArea = M * N\n\tdominoes = int(Area / 2)\n\tprint(dominoes)\n","(n, m) = [int(x) for x in input().split()]\nresult = n * m // 2\nprint(result)\n","(n, m) = tuple((int(x) for x in input().split()))\n(ns, nr) = divmod(n, 2)\n(ms, mr) = divmod(m, 2)\nprint(ms * n + mr * ns)\n","inc = 0\ndomino = 2\n(num1, num2) = map(int, input().split())\narea = num1 * num2\nif num1 >= 1 or num2 >= 1 or num1 <= 16 or (num2 <= 16):\n\tfor x in range(area):\n\t\tif area >= 2:\n\t\t\tarea = area - domino\n\t\t\tinc += 1\nprint(inc)\n","totIn = str(input())\ntotList = totIn.split()\nm = int(totList[0])\nn = int(totList[1])\ntotSquare = m * n\nplacedDominos = 0\nfor i in range(0, totSquare):\n\twhile totSquare >= 2:\n\t\ttotSquare -= 2\n\t\tplacedDominos += 1\nprint(placedDominos)\n","(m, n) = input().split()\nm1 = int(m)\nm2 = int(n)\np = m1 * m2\nt = int(p / 2)\nprint(t)\n","(x, y) = [int(x) for x in input().split()]\narea_of_rectangle = x * y\nCan_fit = 2\nnum_of_dominoes = area_of_rectangle // Can_fit\nprint(num_of_dominoes)\n","N = input().split()\nfor i in range(len(N)):\n\tN[i] = int(N[i])\nx = N[0] * N[1]\nk = x // 2\nprint(k)\n","(m, n) = input().split()\n(m, n) = (int(m), int(n))\ns = 0\nr = n * m\nwhile r - 2 >= 0:\n\tr = r - 2\n\ts += 1\nprint(s)\n","(a, b) = [int(i) for i in input().split()]\nif a * b % 2 == 0:\n\tprint(a * b // 2)\nelse:\n\tprint((a * b - 1) // 2)\n","l1 = [int(x) for x in input().split()]\narea = l1[0] * l1[1]\nif area % 2 == 0:\n\tprint(int(area / 2))\nelse:\n\tprint(int((area - 1) / 2))\n","(x, y) = input().split()\nx = int(x)\ny = int(y)\nx_x = x % 2\ny_y = y % 2\nif x_x + y_y == 2:\n\tz = (x * y - 1) / 2\nelse:\n\tz = x * y / 2\nprint(int(z))\n","(m, n) = list(map(int, input().split()))\ncount = 0\nfor raw in range(n):\n\tcount += m / 2\nprint(int(count))\n","(M, N) = map(int, input().split())\nasd = M * N // 2\nprint(asd)\n","(m, n) = map(int, input().split())\nc = 0\nr = n % 2\nq = (n - r) // 2\nc = q * m\nif r == 1:\n\tc += m // 2\nprint(c)\n","aux = input()\naux = aux.split()\nn = int(aux[0])\nm = int(aux[1])\nans = n * m // 2\nprint(ans)\n","number = input().split()\nnum1 = int(number[0])\nnum2 = int(number[1])\nr = num1 * num2\nprint(r // 2)\n","str_0 = input()\nlist_0 = str_0.split(' ')\nm = int(list_0[0])\nn = int(list_0[1])\nn_1 = n // 2\nif n % 2 == 0:\n\tprint(n_1 * m)\nelse:\n\tprint(n_1 * m + m // 2)\n","(m, n) = [int(x) for x in input().split()]\narea_left = m * n\ntotal = 0\nwhile area_left >= 2:\n\tarea_left -= 2\n\ttotal += 1\nprint(total)\n","import math\n(a, b) = input().split()\na = int(a)\nb = int(b)\nprint(math.floor(a * b / 2))\n","from math import floor\n\ndef cin(func):\n\treturn [func(x) for x in input().split()]\n(m, n) = cin(int)\nprint(floor(m * n / 2))\n","string = input()\nstring1 = string.split(' ')\nresult = int(string1[0]) * int(string1[1]) // 2\nprint(result)\n","(M, N) = input('').split()\nM = int(M)\nN = int(N)\narea = M * N\na = 2\nb = 1\ncount = area // 2\nprint(count)\n","inp = input().split(' ')\nm = int(inp[0])\nn = int(inp[1])\nif m % 2 == 0:\n\tprint(m // 2 * n)\nelif n % 2 == 0:\n\tprint(n // 2 * m)\nelse:\n\tprint((m - 1) // 2 * n + (n - 1) // 2)\n","(a, b) = input().split(' ')\n(a, b) = (int(a), int(b))\nsol = int(a * b / 2)\nprint(sol)\n","M_N = input().split()\nM = int(M_N[0])\nN = int(M_N[1])\nvivod = M * N // 2\nprint(vivod)\n","from math import floor\n\ndef fun():\n\tstr = input().strip().split()\n\t(n, m) = (int(str[0]), int(str[1]))\n\ta = n * m\n\treturn int(floor(a / 2))\nprint(fun())\n","import math\n(m, n) = map(int, input().split())\nsquares = m * n\nminVal = math.floor(m * n / 2)\nprint(minVal)\n","bord = input()\ndomino = 2\nb = bord.split(' ')\n(M, N) = (int(b[0]), int(b[1]))\nif M * N % 2 == 0:\n\tans1 = M * N / domino\nelse:\n\tans1 = (M * N - 1) / domino\nprint(int(ans1))\n","inp = input().split(' ')\nM = int(inp[0])\nN = int(inp[1])\n\ndef calculate_result(M, N):\n\tif M % 2 == 0:\n\t\treturn M / 2 * N\n\tif N % 2 == 0:\n\t\treturn N / 2 * M\n\telse:\n\t\treturn (M * N - 1) / 2\nres = calculate_result(M, N)\nprint(int(res))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m * n % 2 == 0:\n\tx = int(m * n / 2)\n\tprint(x)\nelse:\n\tx = int(m * n // 2)\n\tprint(x)\n","import math\n(m, n) = map(lambda x: int(x), input().split())\nk = m * n\nc = k / 2\nif k % 2 > 0:\n\tprint(math.floor(c))\nelse:\n\tprint(int(c))\n","(x, y) = map(int, input().strip().split())\nboard_size = x * y\nresult = 0\nif board_size % 2 == 0:\n\tresult = board_size // 2\nelse:\n\tresult = (board_size - 1) // 2\nprint(result)\n","n = input().split(' ')\np = int(n[0]) * int(n[1])\nif p % 2 == 0:\n\tprint(int(p / 2))\nelse:\n\tprint(int(p / 2 - 0.5))\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nans = 0\nif n % 2 == 0:\n\tans = n / 2 * m\nelif m % 2 == 0:\n\tans = m / 2 * n\nelse:\n\tans = n // 2 * m\n\tans += m // 2\nprint(int(ans))\n","board_dimensions = input().split(' ')\nnum_dominos = int(board_dimensions[0]) * int(board_dimensions[1]) // 2\nprint(num_dominos)\n","(m, n) = map(int, input().split(' '))\nx = m * n\nans = x // 2\nprint(ans)\n","import math\nx = input()\n(m, n) = (int(x.split()[0]), int(x.split()[1]))\nif m % 2 != 0 and n % 2 != 0:\n\ta = math.floor(m / 2)\n\tb = math.floor(n / 2)\n\tc = b * m + a\n\tprint(int(c))\nelif m % 2 == 0 and n % 2 != 0:\n\ta = m / 2\n\tb = math.floor(n / 2)\n\tc = m * b + a\n\tprint(int(c))\nelif m % 2 != 0 and n % 2 == 0:\n\ta = n / 2\n\tc = m * a\n\tprint(int(c))\nelse:\n\ta = m / 2\n\tc = a * n\n\tprint(int(c))\n","m_n = [int(x) for x in input().split()]\nprint(m_n[0] * m_n[1] // 2)\n","a = input()\na = a.split(' ')\nf = int(a[0]) * int(a[1])\nprint(f // 2)\n","a = input().split()\nb = int(a[0]) * int(a[1])\nc = 0\nz = 0\nwhile b > 1:\n\tif b % 2 == 0:\n\t\tb = b - 2\n\t\tc += 1\n\telse:\n\t\tb = b - 2\n\t\tz += 1\nprint(c + z)\n","n = input().split()\n(m, n) = (int(n[0]), int(n[1]))\nif m == n == 1:\n\tprint('0')\nif m % 2 == 0 and (m != 1 or n != 1):\n\tx = m / 2 * n\n\tprint(int(x))\nif m % 2 != 0 and (m != 1 or n != 1):\n\tx = m // 2 * n + n // 2\n\tprint(int(x))\n","from sys import stdin, stdout\n(a, b) = stdin.read().split()\n(a, b) = (int(a), int(b))\nif a % 2 != 0 and b % 2 != 0:\n\tc = (a * b - 1) // 2\nelse:\n\tc = a * b // 2\nstdout.write(str(c))\n","a = input().split()\nif int(a[0]) % 2 == 0 or int(a[1]) % 2 == 0:\n\tprint(int(int(a[0]) * int(a[1]) / 2))\nelse:\n\tprint(int((int(a[0]) * int(a[1]) - 1) / 2))\n","import sys\nnums = sys.stdin.readline().split(' ')\nm = int(nums[0])\nn = int(nums[1])\nprint(m * n // 2)\n","def check(m, n):\n\tcounter = 0\n\twhile m >= 2:\n\t\tcounter += n\n\t\tm -= 2\n\tif m == 1:\n\t\twhile n > 1:\n\t\t\tcounter += 1\n\t\t\tn -= 2\n\treturn counter\n(m, n) = [int(elem) for elem in input().split()]\nprint(check(m, n))\n","(m, n) = map(lambda x: int(x), input().split())\nif m < n:\n\t(m, n) = (n, m)\ntotal = 0\ntotal += m // 2 * n\nif m % 2 == 1:\n\t(m, n) = (n, m % 2)\n\ttotal += m // 2\nprint(total)\n","data = input()\ndataList = data.split(' ')\nm = int(dataList[0])\nn = int(dataList[1])\narea = m * n\nmax_domino = area // 2\nprint(max_domino)\n","import math\n(m, n) = map(int, input().split())\ndies_size = 2 * 1\ndies_needed = m * n / dies_size\nprint(math.floor(dies_needed))\n","r = 2\nc = 1\nx = input().split()\nm = int(x[0])\nn = int(x[1])\nj = int(m / r)\nk = int(n / c)\nl = m - r * j\nh = n - c * k\nresult = k * j\nif l > 0 and l >= c and (r <= n):\n\ttemp_m = l\n\ttemp_n = n\n\ttemp_c = r\n\ttemp_r = c\n\ttemp_j = int(temp_m / temp_r)\n\ttemp_k = int(temp_n / temp_c)\n\tresult += temp_j * temp_k\nelif h > 0 and h >= r and (c <= m):\n\ttemp_m = m\n\ttemp_n = h\n\ttemp_c = r\n\ttemp_r = c\n\ttemp_j = int(temp_m / temp_r)\n\ttemp_k = int(temp_n / temp_c)\n\tresult += temp_j * temp_k\nprint(int(result))\n","import sys\nm_and_n = input()\nm_and_n = m_and_n.split()\nm = int(m_and_n[0])\nn = int(m_and_n[1])\nproduct = int(m) * int(n)\nwhile True:\n\tif product % 2 == 0:\n\t\tprint(int(product / 2))\n\t\tbreak\n\tproduct -= 1\n\tif product == 0:\n\t\tprint(0)\n\t\tbreak\n","input = input().split()\nsize = int(input[0]) * int(input[1])\nwhile True:\n\tif size % 2 == 0:\n\t\tbreak\n\telse:\n\t\tsize -= 1\nprint(size // 2)\n","nk = input().split()\nn = int(nk[0])\nk = int(nk[1])\nprint(n * k // 2)\n","n = input()\nb = n.split()\nc = int(b[0]) * int(b[1])\nf = c // 2\nprint(f)\n","line = input()\narr = line.split()\nsum = 0\na = int(arr[0])\nb = int(arr[1])\ntemp1 = a // 2\nsum = temp1 * b\ntemp2 = a % 2\nif temp2 == 1:\n\tsum += b // 2\nprint(int(sum))\n","(M, N) = map(int, input().split())\nprint(M * N // (2 * 1))\n","while True:\n\ttry:\n\t\tl = input().split()\n\t\tM = int(l[0])\n\t\tN = int(l[1])\n\t\ts = M * N\n\t\ta = s // 2\n\t\tprint(a)\n\texcept EOFError:\n\t\tbreak\n","(M, N) = input().split()\nsquare = int(M) * int(N)\ntemp = int(square / 2)\nprint(temp)\n","import math\n(m, n) = [int(x) for x in input().split()]\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\nc = int(n / 2)\nd = int(m / 2)\nif n % 2 == 0:\n\tprint(c * m)\nelse:\n\tprint(c * m + d)\n","content = input().split()\nm = int(content[0])\nn = int(content[1])\nif m % 2 == 0:\n\tx = int(m / 2) * n\nelse:\n\tx = int(m / 2) * n + int(n / 2)\nprint(x)\n","a = input().split(' ')\nploshad = int(a[0]) * int(a[1])\ncheck = ploshad // 2\nprint(str(check))\n","a = input().split()\nM = int(max(a))\nN = int(min(a))\nnum = int(M / 2) * N + int(N / 2) * (M % 2)\nprint(num)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nproduct = n * m\nprint(product // 2)\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\nno = math.floor(m * n / 2)\nprint(no)\n","a = input()\nb = a.split(' ')\nc = []\nfor i in b:\n\tc.append(int(i))\nz = c[0] * c[1] // 2\nprint(z)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nar = a * b\nbr = 2\nc = 0\nwhile br <= ar:\n\tc += 1\n\tbr = br + 2\nprint(c)\n","a = list(input().split(' '))\nm = int(a[0])\nn = int(a[1])\nk = m * n\nz = k // 2\nprint(z)\n","(m, n) = (int(v) for v in input().split())\nprint(m * n // 2)\n","nums = input()\nnums = nums.strip().split()\nm = int(nums[0])\nn = int(nums[1])\ntotal = m * n\nprint(total // 2)\n","ip = input().split()\n(m, n) = (int(ip[0]), int(ip[1]))\nif m == 1:\n\tprint(n // 2)\nelif n == 1:\n\tprint(m // 2)\nelif m % 2 == 0 and n % 2 == 0:\n\tprint(m * n // 2)\nelif n % 2 == 0:\n\tprint(m * n // 2)\nelse:\n\tprint(m * (n - 1) // 2 + m // 2)\n","p = input().split()\nprint(int(p[0]) * int(p[1]) // 2)\n","from sys import stdin, stdout\n(m, n) = map(int, stdin.readline().split())\nstdout.write(f'{m * n // 2}\\n')\n","import math\nar = str.split(input())\nM = int(ar[0])\nN = int(ar[1])\nif 1 <= M <= N <= 16:\n\tif M % 2 == 1:\n\t\tx = math.floor(M / 2) * N\n\t\ty = math.floor(N / 2)\n\t\tprint(x + y)\n\tif M % 2 == 0:\n\t\tx = M / 2 * N\n\t\tprint(int(x))\n","(x, y) = map(int, input().split())\na = x * y\nprint(int(a / 2))\n","(M, N) = input().split()\nout = int(M) * int(N) // 2\nprint(out)\n","import sys\nimport collections\nimport math\nimport functools\nimport itertools\nimport bisect\nimport operator\nimport heapq\nimport random\ntrue = True\nfalse = False\nnull = None\ntcid = 0\n\ndef ceil(a, b):\n\tans = a // b\n\tif a % b != 0:\n\t\tans += 1\n\treturn ans\n\ndef perr(*args, **kwargs):\n\tprint(*args, file=sys.stderr, **kwargs)\n\ndef line():\n\tln = sys.stdin.readline().strip()\n\tif ln == '':\n\t\tsys.exit()\n\treturn ln\n\ndef lines(n):\n\treturn [line() for i in range(n)]\n\ndef split(ln=None):\n\treturn (ln or line()).split()\n\ndef parse(*parsers):\n\treturn list(map(lambda p, w: p(w), parsers, split()))\n\ndef nums(o=None):\n\tif o is not None:\n\t\tif isinstance(o, int):\n\t\t\to = lines(o)\n\t\telif isinstance(o, str):\n\t\t\to = split(o)\n\treturn list(map(int, o or split()))\n\ndef num():\n\treturn int(line())\n\ndef solve(tcid=1):\n\t(m, n) = nums()\n\tprint(m * n // 2)\nwhile true:\n\ttcid += 1\n\tsolve(tcid)\n","line = [int(x) for x in input('').strip().split(' ')]\nm = line[0]\nn = line[1]\nprint(m * n // 2)\n","print(eval('*'.join(input().split())) // 2)\n","a = input().split(' ')\nb = int(a[0])\nc = int(a[1])\nf = b * c / 2\nprint(int(f))\n","lst = list(map(int, input().split()))\n(n, m) = (lst[0], lst[1])\nprod = n * m\nprint(prod // 2)\n","(m, n) = map(int, input().split(' '))\nif n == 1 or m == 1:\n\tif n == 1:\n\t\tprint(m // 2)\n\telif m == 1:\n\t\tprint(n // 2)\nelif m % 2 != 0 and n % 2 != 0:\n\tif m > n:\n\t\te = m\n\t\tr = n\n\telse:\n\t\te = n\n\t\tr = m\n\tu = e - 1\n\tb = u * r // 2\n\tv = r // 2\n\tprint(b + v)\nelse:\n\tfuck = m * n // 2\n\tprint(fuck)\n","(board_width, board_height) = map(int, input().split())\nif board_width % 2 == 0:\n\tno_domino = board_width / 2 * board_height\nelse:\n\tno_domino1 = board_width // 2 * board_height\n\tremaining_places = board_width % 2 * board_height\n\tno_domino2 = remaining_places // 2\n\tno_domino = no_domino1 + no_domino2\nprint(int(no_domino))\n","ln = [int(i) for i in input().split(' ')]\nprint(max([ln[0] // 2 * ln[1] + ln[0] % 2 * (ln[1] // 2), ln[1] // 2 * ln[0] + ln[1] % 2 * (ln[0] // 2)]))\n","import sys\ndbg = False\nif dbg:\n\tsys.stdin = open('input.txt')\ndin = lambda : map(int, input().split())\n(M, N) = din()\nif M * N % 2 == 0:\n\tprint(M * N // 2)\nelse:\n\tprint((M * N - 1) // 2)\n","(m, n) = map(int, input().split())\nboard = m * n\nfit = board // 2\nprint(fit)\n","import sys\nf = sys.stdin\n(n, m) = map(int, f.readline().split())\nres = n * m // 2\nprint(res)\n","(m, n) = [int(i) for i in input().split()]\ntot = m * n\np = 2 * 1\nprint(tot // p)\n","import math\n(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nprint(math.floor(m * n * 0.5))\n","R = lambda : map(int, input().split())\n(n, m) = R()\nans = int(n * m / 2)\nprint(ans)\n","(M, N) = list(map(int, input().rstrip().split()))\ndom = M * N // 2\nprint(dom)\n","(M, N) = [int(i) for i in input().split()]\nn = M * N // 2\nprint(n)\n","(m, n) = map(int, input().split())\nk = m * n\nd = k // 2\nd = int(d)\nprint(d)\n","a = map(int, input().split())\na = list(a)\n(n, m) = (a[0], a[1])\nc = n * m\nprint(int(c / 2))\n","def input_int():\n\treturn int(input())\n\ndef input_int_list():\n\treturn list(map(int, input().split()))\n\ndef input_input_map():\n\treturn map(int, input().split())\n\ndef run():\n\t(m, n) = input_input_map()\n\tprint(m * n // 2)\nrun()\n","val = input()\nval = val.split()\nx = int(val[0])\ny = int(val[1])\nn = 0\nnew = 0\nif y % 2 == 0:\n\tif x % 2 == 0:\n\t\tx = int(x / 2)\n\t\tn = y * x\n\telse:\n\t\tx = (x - 1) / 2\n\t\tn = y * int(x)\n\t\tn = n + int(y / 2)\nelif x % 2 == 0:\n\tx = int(x / 2)\n\tn = y * x\nelse:\n\tnew = int((x - 1) / 2)\n\tn = (y - 1) * new\n\tn = n + int(y / 2) + int(x / 2)\nprint(n)\n","import sys\n\ndef domino_square(n, m):\n\tc = n * m\n\td = 0\n\tif c % 2 == 0:\n\t\td = c // 2\n\telse:\n\t\td = (c - 1) // 2\n\tprint(d)\nfor line in sys.stdin:\n\tparts = line.split(' ')\n\tdomino_square(int(parts[0]), int(parts[1]))\n","tmp = input().split(' ')\nm = int(tmp[0])\nn = int(tmp[1])\nprint(m * n // 2)\n","(x, y) = list(map(int, input().split()))\nprint(x * y // 2)\n","inp = input()\nsize = list(map(int, inp.split()))\nwidth = size[0]\nheight = size[1]\nprint(int(width * height / 2))\n","(m, n) = input().split()\nx = 0\nx = int(m) // 2 * int(n)\ny = 0\nif int(m) % 2 == 1:\n\ty = int(n) // 2\nprint(x + y)\n","def crear_archivo():\n\tarchivo = open('archivo_de_práctica', 'w')\n\tarchivo.close\n\ndef escribir_archivo():\n\tarchivo = open('agenda.nro1', 'a')\n\tcadena = input('introducir nombre de archivo')\n\tarchivo.write(cadena)\n\tarchivo.close\nentrada = input()\nlista = list()\nancho = int(entrada[:entrada.find(' ')])\nlargo = int(entrada[entrada.find(' ') + 1:])\narea = ancho * largo\nprint(area // 2)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ntotal_number = m * n / 2\nprint(int(total_number))\n","y = input().split()\na = int(y[0])\nb = int(y[1])\nc = a * b\nx = 0\nfor i in range(2, c + 1, 2):\n\tx = x + 1\nprint(x)\n","inputs = list(map(int, input().rstrip().split()))\nsize = int(inputs[0] * inputs[1])\nnumberoftiles = 0\nif size >= 2:\n\tnumberoftiles = int(size / 2)\nprint(numberoftiles)\n","p = list(map(int, input().split()))\nprint(int(p[0] * p[1] / 2))\n","import sys\nimport math\nimport bisect\nimport re\n\ndef main():\n\t(n, m) = map(int, input().split())\n\tprint(n * m // 2)\nmain()\n","inpt = [int(x) for x in input().split()]\nans = int(inpt[0] * inpt[1] / 2)\nprint(ans)\n","nums = input()\nnums = nums.split()\n(m, n) = (int(nums[0]), int(nums[1]))\ncount = m * n / 2\nprint(int(count))\n","m = input()\nn = m.split(' ')\nprint(str(int(n[0]) * int(n[1]) // 2))\n","(x, y) = map(int, input().split())\np = min(x, y) // 1\nq = max(x, y) // 2\nz = p * q\ns = abs(p * q * 2 - x * y) // 2\nprint(s + z)\n","inp = input().split(' ')\nM = int(inp[0])\nN = int(inp[1])\nM1 = M - M % 2\nN1 = N - N % 2\nC = M1 * N1 / 2\nresult = 0\nif M % 2 == 1 or N % 2 == 1:\n\tif M % 2 == 1 and N % 2 == 1:\n\t\tresult = C + M1 / 2 + N1 / 2\n\telif M % 2 == 1 and N % 2 == 0:\n\t\tresult = C + N / 2\n\telse:\n\t\tresult = C + M / 2\nelse:\n\tresult = C\nprint(str(int(result)))\n","(a, b) = map(int, input().split())\nar = 2\nc = 0\nt = 0\nwhile t < a * b - 1:\n\tc += 1\n\tt = c * ar\nprint(c)\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nmsr1 = int(m / 2)\nmsr = msr1 * n\nrem = m % 2\nnsr = rem * n\nnsr1 = int(nsr / 2)\nr = msr + nsr1\nprint(r)\n","a = [int(x) for x in input().split()]\nprint(a[0] * a[1] // 2)\n","(m, n) = map(int, input().split())\nlist = [m, n]\na = max(list)\nb = min(list)\nif a % 2 == 0:\n\tnum = b * (a // 2)\nelse:\n\tnum = b * (a // 2) + b // 2\nprint(num)\n","t = input()\na = t.split(' ')\nm = int(a[0])\nn = int(a[1])\nif 1 <= m <= n <= 16:\n\tp = int(m * n / 2)\n\tprint(p)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\narea = m * n\nif area % 2 != 0:\n\tprint(area // 2)\nelse:\n\tprint(area // 2)\n","(n, k) = map(int, input().split())\nv = n * k // 2\nprint(v)\n","(l, b) = list(map(int, input().split()))\nprint(l * b // 2)\n","vals = input()\nm = int(vals.split()[0])\nn = int(vals.split()[1])\nprint(int(m * n / 2))\n","_boardSize = [int(x) for x in input().split(' ')]\nboardSize = _boardSize[0] * _boardSize[1]\nif boardSize % 2 == 1:\n\tprint((boardSize - 1) // 2)\nelse:\n\tprint(boardSize // 2)\n","(n, m) = [int(i) for i in input().split()]\nans = int(n * m / 2)\nprint(ans)\n","def main():\n\t(m, n) = [int(x) for x in input().strip().split()]\n\tif m % 2 == 0 and n % 2 == 0:\n\t\tprint(int(m * n / 2))\n\telif m % 2 == 0 and n % 2 != 0:\n\t\tprint(int(m * n / 2))\n\telif n % 2 == 0 and m % 2 != 0:\n\t\tprint(int(m * n / 2))\n\telse:\n\t\tprint(int((m - 1) / 2 + m * (n - 1) / 2))\nmain()\n","l = []\n(a, b) = map(int, input().split())\nl.append(a)\nl.append(b)\nm = a * b\nn = 2 * 1\ne = m // n\nprint(e)\n","def f(a, b):\n\tr = a // 2 * b\n\tif a % 2 == 1:\n\t\tr += b // 2\n\treturn r\ns = input().split(' ')\n(m, n) = [int(s[i]) for i in range(0, 2)]\nprint(max(f(m, n), f(n, m)))\n","user = input().split()\nprod = int(user[0]) * int(user[1])\nrem = prod // 2\nprint(rem)\n","import math\n\ndef DominoPilling(m, n):\n\treturn math.floor(m * n / 2)\n(m, n) = input().split()\nprint(DominoPilling(int(m), int(n)))\n","n = list(map(int, input().strip().split(' ')))\nif n[1] * n[0] % 2 == 0:\n\tprint(n[1] * n[0] // 2)\nelse:\n\tprint((n[0] * n[1] - 1) // 2)\n","(m, n) = map(int, input().split())\nz = m * n\nd = z // 2\nprint(d)\n","(m, n) = map(int, input().split(' '))\ntotal = m // 2 * n\nif m % 2 == 1:\n\ttotal += n // 2\nprint(total)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nif 1 <= a <= b <= 16:\n\td = a * b\n\te = int(d / 2)\n\tprint(e)\n","(a, b) = map(int, input().strip().split())\nc = a * b\nprint(c // 2)\n","(M, N) = [int(x) for x in input().split()]\nif M % 2 == 0 or N % 2 == 0:\n\tm = M * N / 2\nelse:\n\tm = (M * N - 1) / 2\nf = int(m)\nprint(f)\n","(n, d) = map(int, input().split())\nprint(n * d // 2)\n","while True:\n\ttry:\n\t\ta = []\n\t\ta = input().split(' ')\n\t\tfor i in range(len(a)):\n\t\t\ta[i] = int(a[i])\n\t\tif a[0] * a[1] & 1:\n\t\t\tcon = (a[0] * a[1] - 1) / 2\n\t\telse:\n\t\t\tcon = a[0] * a[1] / 2\n\t\tprint(int(con))\n\texcept:\n\t\tbreak\n","import math\ns = input().split()\nprint(math.floor(int(s[0]) * int(s[1]) / 2))\n","def DominoPiling():\n\tinputs = input().split()\n\tmn = int(inputs[0]) * int(inputs[1])\n\treturn int(mn / 2)\nprint(DominoPiling())\n","(m, n) = [int(_) for _ in input().split()]\nprint(m // 2 * n + m % 2 * n // 2)\n","(n, m) = map(int, input().split())\nans = 0\nrandint = 0\nif m >= 1 and m <= 16 and (n <= 16) and (n >= 1):\n\tif n % 2 == 1 and m % 2 == 1:\n\t\trandint = n * m\n\t\tans = randint / 2 - 0.5\n\t\tprint(int(ans))\n\telse:\n\t\trandint = n * m\n\t\tans = randint / 2\n\t\tprint(int(ans))\n","(m, n) = [int(i) for i in input().split(' ')]\nr = m * n // 2\nprint(r)\n","count = 0\n(n, k) = map(int, input().split())\nt = n * k\nif t % 2 == 0:\n\tcount = t // 2\nelse:\n\tt -= 1\n\tcount = t // 2\nprint(count)\n","my_input = input()\n(a, b) = my_input.split()\na = int(a)\nb = int(b)\n\ndef dominos(m, n):\n\treturn print(m * n // 2)\ndominos(a, b)\n","from sys import stdin\ninput_list = [int(i) for i in stdin.readline().split(' ')]\n(m, n) = input_list\nprint(int(m * n / 2))\n","size = input().split(' ')\nlimit = int(size[0]) * int(size[1])\nanswer = int(limit / 2)\nprint(answer)\n","input_data = input()\nlist_we_use = input_data.split(' ')\nh = []\nfor i in list_we_use:\n\th.append(int(i))\nn = h[0] * h[1]\nprint(n // 2)\n","import sys\ndata = sys.stdin.readlines()\nm = int(data[0].split()[0])\nn = int(data[0].split()[1])\na = m // 2 * n\nif m % 2 != 0:\n\ta += n // 2\nprint(a)\n","n = input().split()\na = int(n[0])\nb = int(n[1])\nanswer = int(a * b / 2)\nprint(answer)\n","(m, n) = list(map(int, input().strip().split()))\nans = m * n // 2\nprint(ans)\n","(M, N) = [int(x) for x in input().split()]\nif N == 1 and M == 1:\n\tprint(0)\nelse:\n\tprint(N * M // 2)\n","def domino(n, m):\n\tarea = n * m\n\tcount = area // 2\n\treturn count\n(n, m) = map(int, input().split())\nprint(domino(n, m))\n","from sys import stdin\n\ndef main():\n\t(a, b) = [int(c) for c in stdin.readline().strip().split()]\n\tprint(a * b // 2)\nmain()\n","digit = input().split()\nfor i in range(2):\n\tdigit[i] = int(digit[i])\ndiv = digit[0] * digit[1] / 2\nprint(int(div))\n","mn = input().split()\nm = int(mn[0])\nn = int(mn[1])\nif n * m % 2 == 0:\n\tprint(n * m // 2)\nelse:\n\tprint((n * m - 1) // 2)\n","i = lambda : map(int, input().split())\n(m, n) = i()\nprint(int(m * n / 2))\n","def getdcount(m, n):\n\tc = m // 2 * n\n\tif m % 2:\n\t\tc += n // 2\n\treturn c\n(m, n) = tuple(map(int, input().split()))\nprint(getdcount(m, n))\n","f = list(map(int, input().split()))\nprint(int(f[0] * f[1] / 2))\n","nums = list((int(i) for i in input().split()))\nresult = 0\nm2 = nums[0]\nwhile nums[1] > 1:\n\tm1 = nums[0]\n\twhile m1 > 0:\n\t\tresult += 1\n\t\tm1 -= 1\n\tnums[1] -= 2\nif nums[1] == 1:\n\twhile m2 > 1:\n\t\tresult += 1\n\t\tm2 -= 2\nprint(result)\n","(m, n) = list(map(int, input().split()))\nt = 2 * 1\na = m * n\nprint(a // t)\n","import math\nx = input()\nwymiar = []\nfor i in x.split(' '):\n\twymiar.append(int(i))\npole = wymiar[0] * wymiar[-1]\ny = pole / 2\nif pole % 2 == 0:\n\tprint(int(y))\nelse:\n\tprint(int(math.floor(y)))\n","a = input()\na = a.split()\nz = int(a[0])\nt = int(a[1])\np = z * t\nif p % 2 == 0:\n\tm = int(p / 2)\nelse:\n\tm = int((p - 1) / 2)\nprint(m)\n","def dominoshka():\n\tinput_ = [int(i) for i in input().split()]\n\tarea = input_[0] * input_[1]\n\tprint(area // 2)\ndominoshka()\n","inp = input()\ndata = inp.split()\narea = int(data[0]) * int(data[1])\nprint(area // 2)\n","(a, b) = map(int, input().split())\ns = a * b\npiece = s // 2\nprint(piece)\n","l = input()\nl = l.split()\nm = int(l[0])\nn = int(l[1])\nr = m * n // 2\nprint(r)\n","class domino:\n\n\tdef __init__(self, m, n):\n\t\tself.m = m\n\t\tself.n = n\n\t\tself.count = 0\n\n\tdef compute(self):\n\t\tarea = self.m * self.n\n\t\trem = area % 2\n\t\tif rem == 0:\n\t\t\tself.count = int(area / 2)\n\t\telse:\n\t\t\tself.count = int(area / 2)\n\n\tdef output(self):\n\t\tprint(self.count)\n\n\tdef execute(self):\n\t\tself.compute()\n\t\tself.output()\n\ndef main():\n\tstr1 = input()\n\tlist1 = str1.split()\n\ta = int(list1[0])\n\tb = int(list1[1])\n\td1 = domino(a, b)\n\td1.execute()\nmain()\n","(n, m) = map(int, input().split())\nprint(max(n, m) * min(n, m) // 2)\n","(m, n) = [int(x) for x in input().split()]\narea = m * n\ncount = area // 2\nprint(count)\n","def ans() -> int:\n\t(x, y) = [int(x) for x in input().split()]\n\tarea = x * y\n\tif area == 1:\n\t\treturn 0\n\tif area % 2 == 0:\n\t\treturn area / 2\n\telse:\n\t\treturn (area - 1) / 2\nprint(int(ans()))\n","(m, n) = list(map(lambda x: int(x), input().split(' ')))\nif m * n > 1:\n\tprint(int(m * n / 2))\nelse:\n\tprint(0)\n","m = list(map(int, input().split()))\narea = m[0] * m[1]\nrequired = int(area / 2)\nprint(required)\n","inputList = input().split()\nfor i in range(len(inputList)):\n\tinputList[i] = int(inputList[i])\nn = inputList[0]\nm = inputList[1]\nans = n * (m // 2)\nif m % 2 != 0:\n\tans += n // 2\nprint(str(ans))\n","w = input().split()\n(m, n) = (int(w[0]), int(w[1]))\nprint(int(m * n / 2))\n","def domino(m, n):\n\tdom_len = 2\n\tdom_width = 1\n\tarea = m * n\n\tnumber_need = area // (dom_len * dom_width)\n\tprint(number_need)\ndomino(*map(int, input().split()))\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nx_dom = 2\ny_dom = 1\nprint(int(int(m * n) / (x_dom * y_dom)))\n","try:\n\t(n, m) = map(int, input().split())\n\tcnt = 0\n\tif n % 2 != 0 and m % 2 != 0:\n\t\tcnt = (n - 1) * m / 2 + (m - 1) / 2\n\telse:\n\t\tcnt = n * m / 2\n\tprint(int(cnt))\nexcept ValueError:\n\tprint('Unexpected value')\n","m = input().split()\nif 1 <= int(m[0]) <= int(m[1]) <= 16:\n\tres = int(m[0]) * int(m[1]) * 0.5\n\tprint(int(res))\n","from sys import stdin\n(M, N) = map(int, stdin.readline().split())\nprint(M * N // 2)\n","s = input().strip()\nls = s.split(' ')\nwidth = int(ls[0])\nheight = int(ls[1])\nmax_num_of_dominos = 0\nif 1 <= width <= height <= 16:\n\tboard_size = width * height\n\tmax_num_of_dominos = int(board_size / 2)\nprint(max_num_of_dominos)\n","l = list(map(int, input().split(' ')))\nn = int(l[0])\nm = int(l[1])\na = n\nb = m\nt = 0\nwhile b > 0:\n\tsum = a * b\n\tif sum % 2 == 0:\n\t\tt = int(sum / 2)\n\t\tt = t + int((m - b) * a / 2)\n\t\tbreak\n\telse:\n\t\tb -= 1\nprint(t)\n","x = input().split()\nm = int(x[0])\nn = int(x[1])\nif m * n % 2 == 0:\n\tk = m * n / 2\n\tprint(int(k))\nelif m * n % 2 == 1:\n\tl = m * n / 2 - 0.5\n\tprint(int(l))\n","import math\n(n, k) = (input().split(), 1)\nfor i in n:\n\tk = k * int(i)\nprint(math.floor(k / 2))\n","mn = list(map(int, input().split()))\nm = mn[0]\nn = mn[1]\ntileArea = 2 * 1\nboardArea = m * n\nprint(boardArea // tileArea)\n","(n, k) = input('').split()\nx = int(n) * int(k)\nz = int(x / 2)\nprint(z)\n","import math\n(M, N) = map(int, input().split())\nk = M * N / 2\nprint(math.floor(k))\n","q = input().split()\nif int(q[0]) * int(q[1]) % 2 > 0:\n\tprint((int(q[0]) * int(q[1]) - 1) // 2)\nelse:\n\tprint(int(q[0]) * int(q[1]) // 2)\n","import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, copy, functools\n\ndef I():\n\treturn int(sys.stdin.readline())\n\ndef LI():\n\treturn [int(x) for x in sys.stdin.readline().split()]\n\ndef main():\n\t(n, m) = map(int, input().split())\n\treturn n * m // 2\nprint(main())\n","print([int(n * m / 2) for (n, m) in [map(int, input().rstrip().split())]][0])\n","def count(char1, char2):\n\treturn char1 // 2 * char2\n(M, N) = map(int, input().split())\nif M % 2 == 0:\n\tprint(int(count(M, N)))\nelif N % 2 == 0:\n\tprint(int(count(N, M)))\nelse:\n\tprint(int(count(M - 1, N) + N / 2))\n","import math\nnumbers = [int(i) for i in input().split()]\nif numbers[0] % 2 == 1 or numbers[1] % 2 == 1:\n\ts = math.floor(numbers[0] * numbers[1] / 2)\nelse:\n\ts = int(numbers[0] * numbers[1] / 2)\nprint(s)\n","import math\ni = lambda : map(int, input().split())\n(n, k) = i()\nprint(math.floor(n * k / 2))\n","def validate_data(m, n):\n\tif m <= 0 or n <= 0:\n\t\treturn False\n\telif m > n:\n\t\treturn False\n\telif m > 16 or n > 16:\n\t\treturn False\n\treturn True\n\ndef op(m, n):\n\tmatrix = [[0] * n for _ in range(m)]\n\tcont = 0\n\tfor i in range(m):\n\t\tfor j in range(n):\n\t\t\tif matrix[i][j] == 0:\n\t\t\t\tif j + 1 < n and matrix[i][j + 1] == 0:\n\t\t\t\t\tmatrix[i][j] = 1\n\t\t\t\t\tmatrix[i][j + 1] = 1\n\t\t\t\t\tcont += 1\n\t\t\t\telif i + 1 < m and matrix[i + 1][j] == 0:\n\t\t\t\t\tmatrix[i][j] = 1\n\t\t\t\t\tmatrix[i + 1][j] = 1\n\t\t\t\t\tcont += 1\n\tprint(cont)\n(m, n) = map(int, input().split())\nif validate_data(m, n) == True:\n\top(m, n)\n","(a, b) = list(map(int, input().split()))\nc = a * b\nprint(c // 2)\n","(n, k) = map(int, input().split())\nj = int(n * k / 2)\nprint(j)\n","import sys\n(n, k) = input().split()\nm = int(min(n, k))\nm1 = int(max(n, k))\nprint(m // 2 * m1 + m % 2 * (m1 // 2))\n","(a, b) = map(int, input('').split())\nans = int(a * b / 2)\nprint(ans)\n","a = [int(i) for i in input().split()]\nif 1 <= a[0] <= a[1] <= 16:\n\tprint(a[0] * a[1] // 2)\n","__author__ = 'Utena'\nn = list(map(int, input().split()))\nprint(int(n[0] * n[1] / 2))\n","(M, N) = map(int, input().split())\nm = M % 2\nn = N % 2\nif m * n == 0:\n\tnumber = M * N / 2\nelse:\n\tnumber = M * N / 2 - 1 / 2\nprint(int(number))\n","(m, n) = [int(x) for x in input().split()]\nm1 = int(m / 2)\nm2 = m - m1 * 2\nn1 = int(n / 2)\nnum = m1 * n + m2 * n1\nprint(num)\n","(n, m) = map(int, input().split())\na = max(n, m)\nb = min(n, m)\ncount = 0\ncount = a * (b // 2)\ntemp = b % 2\nif temp == 1:\n\tcount += a // 2\nprint(count)\n","import sys\n(m, n) = sys.stdin.readline().split()\n(m, n) = (int(m), int(n))\nc = m * n // 2\nsys.stdout.write(str(c) + '\\n')\n","tmp = input().split(' ')\nM = int(tmp[0])\nN = int(tmp[1])\nprint(int(M * N / 2))\n","(m, n) = [int(x) for x in input().split()]\nif m // 2 >= n // 2:\n\tprint(m // 2 * n + m % 2 * (n // 2))\nelse:\n\tprint(n // 2 * m + n % 2 * (m // 2))\n","import math\n(M, N) = map(int, input().split())\nx = math.floor(M / 2)\nrestM = M - x * 2\ny = math.floor(N / 2)\nnumber = x * N + restM * y\nprint(number)\n","a = input()\nb = a.split(' ')\nm = int(b[0])\nn = int(b[1])\narea = m * n\nk = area // 2\nprint(k)\n","number = input()\nsplit_number = number.split()\n(length, width) = (int(split_number[0]), int(split_number[1]))\ntimes = length * width\nif times % 2 == 0:\n\tprint(int(times / 2))\nelse:\n\tprint(int((times - 1) / 2))\n","(m, n) = [int(x) for x in input().split()]\ni = m * n\nj = 2 * 1\ncount = 0\nwhile j <= i:\n\tj += 2 * 1\n\tcount += 1\nprint(count)\n","(i, j) = map(int, input().split())\nprint(int(i * j / 2))\n","x = input()\nx = x.split()\nfirst = int(x[0])\nsecond = int(x[1])\nintnum = first * second / 2\nprint(int(intnum))\n","(a, b) = map(int, input().split())\nprint(round(a * b // 2))\n","k = input().split(' ')\nn = int(k[0])\nm = int(k[1])\nprint(n * m // 2)\n","string = input()\ni = 0\nwhile True:\n\tif string[i] == ' ':\n\t\tbreak\n\ti += 1\na = int(string[0:i + 1])\nb = int(string[i + 1:i + 4])\nprint(int(a * b // 2))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nimport math\nnum = math.floor(n * m / 2)\nprint(num)\n","import math\ninputs = list(map(int, input().split()))\nm = int(inputs[0])\nn = int(inputs[1])\nDominoPiece = 2 * 1\nBoard = m * n\nnum = int(Board / DominoPiece)\nif num % 2 == 0:\n\tprint(num)\nelse:\n\tprint(math.floor(num))\n","l = list(map(int, input().split()))\nx1 = int(l[0])\ny1 = int(l[1])\ntot = x1 * y1\nans = tot // 2\nprint(ans)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 0 or n % 2 == 0:\n\tnum1 = m * n / 2\n\tnum1 = int(num1)\nelse:\n\timport math\n\tnum1 = math.floor(m * n / 2)\n\tnum1 = int(num1)\nprint(num1)\n","(M, N) = input().split(' ')\nM = int(M)\nN = int(N)\nif M % 2 == 1 and N % 2 == 1:\n\tprint(int((M * N - 1) / 2))\nelse:\n\tprint(int(M * N / 2))\n","import math\n(m, n) = map(int, input().split())\nprint(m * n // 2)\n","desk = list(map(int, input().split()))\no = desk[0] * desk[1] // 2\nprint(o)\n","n = input()\n(a, b) = map(int, n.split())\ntotal = a * b\nres = total // 2\nprint(res)\n","import math\ninp = input()\ninp = inp.split(' ')\nM = int(inp[0])\nN = int(inp[1])\narea = M * N\nnumber = area / 2\nprint(math.floor(number))\n","import sys\nimport math\n(n, m) = map(int, input().split(' '))\nprint(math.floor(m * n / 2))\n","input_data = input()\nlist_we_use = input_data.split(' ')\nc = []\nfor i in list_we_use:\n\tc.append(int(i))\nz = c[0] * c[1] / 2\nprint(int(z))\n","a = input()\nb = int(a[:a.find(' ')])\nc = int(a[a.find(' ') + 1:])\nif b * c % 2 == 0:\n\tprint(int(b * c / 2))\nelse:\n\tprint(int((b * c - 1) / 2))\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nans = 0\nanss = 0\nans = m * n\nanss = ans // 2\nprint(anss)\n","(m, n) = (int(x) for x in input().split(' '))\nif m % 2 != 0 and n % 2 != 0:\n\ta = (m - 1) * n\n\tb = a / 2\n\tc = n / 2\n\ts = b + c\n\ts = int(s)\n\tprint(s)\nelse:\n\ta = m * n / 2\n\ta = int(a)\n\tprint(a)\n","l = [int(n) for n in input().split()]\nprint(l[0] * l[1] // 2)\n","input_data = input()\nlist_we_use = input_data.split(' ')\nd = []\nfor i in list_we_use:\n\td.append(int(i))\ns = d[0] * d[1] / 2\nprint(int(s))\n","dom = input().split()\nN = int(dom[0])\nM = int(dom[1])\nprint(int(N * M / 2))\n","rect_board_size = input()\nsquare_board = rect_board_size.split(' ')\nno_of_squares = int(square_board[0]) * int(square_board[1])\nprint(no_of_squares // 2)\n","import sys\n(n, m) = input().split()\nspaces = int(n) * int(m)\nprint(int(spaces / 2))\n","(M, N) = map(int, input().split())\nS = M * N\nif S % 2 == 0:\n\tn = int(S * 0.5)\nelse:\n\tn = int((S - 1) * 0.5)\nprint(n)\n","import sys\ninputs = sys.stdin.readline().split()\nm = int(inputs[0])\nn = int(inputs[1])\np = m * n\nr = p // 2\nprint(r)\n","def s():\n\t(m, n) = [int(x) for x in input().split(' ')]\n\tprint(int(m * n / 2))\ns()\n","line = input().split(' ')\nn1 = int(line[0])\nn2 = int(line[1])\nprint(n1 * n2 // 2)\n","i = input(str())\nh = list(map(int, i.split(' ')))\nsize = h[0] * h[1]\nmaxNo = size // 2\nprint(maxNo)\n","(m, n) = [int(x) for x in input().split()]\ntotal_squares = m * n\nmax_dominoes = total_squares // 2\nprint(max_dominoes)\n","from math import floor\ndoska = input()\n(dl, shir) = doska.split()\ndl = int(dl)\nshir = int(shir)\ndominoshka = 2 * 1\ndoska = dl * shir\notvet = floor(doska / dominoshka)\nprint(otvet)\n","l = input()\na = l.split()\nm = int(a[0])\nn = int(a[1])\nq = int(m / 2)\nr = m - q * 2\nif r == 0:\n\tans = q * n\nelse:\n\tans = q * n + int(n / 2)\nprint(ans)\n","(m, n) = [int(i) for i in input().split()]\na = m * n // 2\nprint(a)\n","i = [int(x) for x in input().split()]\nM = i[0]\nN = i[1]\nif M % 2 == 0:\n\tn = M / 2 * N\nelif N % 2 == 0:\n\tn = N / 2 * M\nelse:\n\tn = (M * N - 1) / 2\nprint(int(n))\n","(a, b) = map(int, input().split())\ninto = a * b\ntot = into / 2\nprint(int(tot))\n","m = list(map(int, input().split()))\nn = 1\nfor i in m:\n\tn *= i\nprint(int(n // 2))\n","masukan = [int(item) for item in input().split(' ')]\nluas = masukan[0] * masukan[1]\nprint(int(luas / 2))\n","def maxPieces(m, n):\n\tresp = 0\n\tif m == 1:\n\t\tresp = int(n / 2)\n\telse:\n\t\tresp = maxPieces(m - 1, n) + int(n / 2)\n\treturn resp\nmsj = input()\ninpu = msj.split()\nans = 0\nm = int(inpu[0])\nn = int(inpu[1])\nif n % 2 == 0:\n\tans = maxPieces(m, n)\nelse:\n\tans = maxPieces(m, n) + int(m / 2)\nprint(ans)\n","a = input()\na = a.split()\nM = int(a[0])\nN = int(a[1])\nprint(M * N // 2)\n","(a, b) = list(map(int, input().split()))\nc = a * b\nd = 2\nn = int(c / 2)\nif n * 2 <= c:\n\tprint(n)\n","import math\n(m, n) = map(int, input().split())\na = 2\nr = range(1, 17)\nif m in r and n in r:\n\tif m * n % a == 0:\n\t\tprint(m * n // a)\n\telif m > a and n > a:\n\t\tc = m * math.floor(n / a) + math.floor(m / a)\n\t\tprint(c)\n\telif m < a:\n\t\tprint(math.floor(n / a))\n\telse:\n\t\tprint(math.floor(m / a))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nsq = m * n\nres = int(sq / 2)\nprint(res)\n","splits = input().split()\nm = int(splits[0])\nn = int(splits[1])\nprint(int(m * n / 2))\n","(m, n) = [int(num) for num in input().split()]\nmatrix = n * m\nif matrix % 2 == 0:\n\tprint(matrix // 2)\nelse:\n\tprint((matrix - 1) // 2)\n","(m, n) = map(int, input().split())\nsq = m * n\nif sq <= 1:\n\tprint(0)\nelif m % 2 == 0 or n % 2 == 0:\n\tprint(int(sq / 2))\nelse:\n\tprint(int(sq / 2))\n","import math\nstring = input()\n(x, y) = string.split(' ')\nx = int(x)\ny = int(y)\nresult = math.floor(x * y / 2)\nprint(result)\n","(M, N) = map(int, input().split())\nif M % 2 == 0:\n\tx = int(M / 2 * N)\nif M % 2 == 1:\n\ta = M // 2 * N\n\tb = N // 2\n\tx = int(a + b)\nprint(x)\n","def Domino():\n\tmn_ = input()\n\tmn = mn_.split()\n\tm = int(mn[0])\n\tn = int(mn[1])\n\tprint(int(n * m / 2))\nDomino()\n","(a, b) = [int(x) for x in input().split()]\ny = a * b\nz = y // 2\nprint(z)\n","s = input()\np = list(map(int, s.split()))\nm = p[0]\nn = p[1]\nif m * n % 2 == 0:\n\tprint(int(n * m / 2))\nelse:\n\tprint(int((m - 1) * n / 2 + n // 2))\n","num = input().split(' ')\nprint(int(int(num[0]) * int(num[1]) / 2))\n","from math import floor\nrdl = input().split()\nprint(floor(int(rdl[0]) * int(rdl[1]) / 2))\n","line1 = input().split()\n(m, n) = (int(line1[0]), int(line1[1]))\nmax_side = max(m, n)\nmin_side = min(m, n)\ndominoes = max_side // 2 * min_side\ndominoes += max_side % 2 * (min_side // 2)\nprint(dominoes)\n","(M, N) = input().split()\n(M, N) = (int(M), int(N))\nk = M * N\nprint(k // 2)\n","import math\n\ndef main():\n\t(a, b) = map(int, input().split())\n\tprint(math.floor(a * b / 2))\nmain()\n","(n, m) = list(map(int, input().split()))\nif n % 2 == 0 or m % 2 == 0:\n\tprint(n * m // 2)\nelse:\n\ts = max(n, m)\n\tl = min(n, m)\n\tprint((s - 1) * l // 2 + l // 2)\n","(n, m) = map(int, input().split())\nrez = int((n - n % 2) * (m - m % 2) / 2)\nprimalatura = m // 2 if n % 2 == 1 else 0\nadoualatura = n // 2 if m % 2 == 1 else 0\nrez = rez + primalatura + adoualatura\nprint(rez)\n","inp = input()\nl = int(inp.split(' ')[0])\nb = int(inp.split(' ')[1])\narea = l * b\nprint(area // 2)\n","import math\nline = input()\npieces = line.split()\nm = int(pieces[0])\nn = int(pieces[1])\nprint(math.floor(m * n / 2))\n","a = input()\naint = a.split(' ')\nfor i in range(2):\n\taint[i] = int(aint[i])\nresult = aint[0] * aint[1] // 2\nprint(result)\n","n = input().split()\nsurface = int(n[0]) * int(n[1])\nnum_of_dominos = surface // 2\nprint(num_of_dominos)\n","from sys import stdin, stdout\n(a, b) = stdin.readline().split()\nc = str(int(int(a) * int(b) / 2))\nstdout.write(c)\n","(x, y) = map(int, input().split())\nm = max(x, y)\nn = min(x, y)\nif m % 2 == 0:\n\tprint(m * n // 2)\nelse:\n\tprint((m - 1) * n // 2 + n // 2)\n","import math\n(n, m) = map(int, input().split())\nval = math.floor(n * m * 0.5)\nprint(val)\n","inp = input()\nboard = inp.split(' ')\nsquares = int(board[0]) * int(board[1])\nprint(squares // 2)\n","(M, N) = [int(s) for s in input().rstrip().split(' ')]\nprint(M * N // 2)\n","import sys\nfor line in sys.stdin:\n\ts = line.split(' ')\n\tm = int(s[0])\n\tn = int(s[1])\n\tprint(m * n // 2)\n\tbreak\n","nXm = list(input().split(' '))\nn = int(nXm[0])\nm = int(nXm[1])\nif n * m % 2 == 0:\n\tprint(n * m // 2)\nelse:\n\tprint((n * m - 1) // 2)\n","(M, N) = map(int, input().split())\nif M >= 1 and N <= 16:\n\tprint(int(M * N / 2))\n","l = []\nbrr = []\narr = str(input())\nbrr = arr.split(' ')\nl = [y for y in brr if y != '']\nprint(int(l[0]) * int(l[1]) // 2)\n","entrada = list((int(x) for x in input().split()))\nprint(entrada[0] * entrada[1] // 2)\n","import math\nboard = input()\nm = int(board.split(' ')[0])\nn = int(board.split(' ')[-1])\narea = m * n\noutput = math.floor(area / 2)\nprint(output)\n","arr = input().split()\nM = int(arr[0])\nN = int(arr[1])\nprint(int(M * N / 2))\n","N = input()\nn = int(N.split()[0])\nm = int(N.split()[1])\np = n * m\nprint(int(p / 2))\n","def Dominopiling():\n\t(m, n) = map(int, input().split())\n\tif m < 1 or m > 16:\n\t\tprint('OOOOPS' + 'Between 1 and 16 please')\n\t\texit()\n\tif n < 1 or n > 16:\n\t\tprint('OOOOPS' + 'Between 1 and 16 please')\n\t\texit()\n\tM = m * n\n\tdomino = M / 2\n\tprint(int(domino))\nDominopiling()\n","from sys import stdin, stdout\n(m, n) = map(int, stdin.readline().split())\nprint(m * n // 2)\n","(len1, len2) = map(int, input().split())\nprint(int(int(len1 * len2) / 2))\n","while True:\n\t(m, n) = [int(x) for x in input('').split()]\n\tif m >= 1 and m <= 16 and (n >= 1) and (n <= 16):\n\t\tbreak\nnum = m * n // 2\nprint(num)\n","a = input()\nc = a.split()\nn_1 = int(c[0]) // 2 * int(c[1])\nif int(c[0]) % 2 != 0:\n\tn_2 = int(c[1]) // 2\nelse:\n\tn_2 = 0\nprint(n_1 + n_2)\n","args = [int(x) for x in input().split(' ')]\nM = args[0]\nN = args[1]\nprint(str(M * N // 2))\n","inp = input().split()\nm = int(inp[0])\nn = int(inp[1])\nmRest = m % 2\ncount = 0\ncount += int(m / 2) * n\nif mRest == 1:\n\tcount += int(n / 2)\nprint(count)\n","import random\nstr1 = input()\n(m, n) = str1.split(' ', 1)\nm = int(m)\nn = int(n)\nif m % 2 == 0 or n % 2 == 0:\n\tret = m * n // 2\nelse:\n\tret = (m * n - 1) // 2\nprint(ret)\n","(n, m) = map(int, input().split(' '))\narea = n * m\ndomino_area = 2 * 1\nprint(area // domino_area)\n","arr = list(map(int, input().split()))\nk = arr[0] * arr[1]\nprint(int(k / 2))\n","(m, n) = map(int, input().split())\ns = m * n\nresult = int(s / 2)\nprint(result)\n","(m, n) = map(int, input().split())\nd = 2\nans = m * n // d\nprint(ans)\n","dimensions = input()\nm_n = dimensions.split()\nm = int(m_n[0])\nn = int(m_n[1])\nif m == 1 and n == 1:\n\tcount = 0\n\tprint(count)\nelse:\n\tif m == 1:\n\t\ti = 0\n\t\td_count = 0\n\t\tif n % 2 == 0:\n\t\t\twhile i < n:\n\t\t\t\ti += 2\n\t\t\t\td_count += 1\n\t\telse:\n\t\t\twhile i <= n:\n\t\t\t\ti += 2\n\t\t\t\td_count += 1\n\t\t\td_count -= 1\n\telif n == 1:\n\t\tj = 0\n\t\td_count = 0\n\t\tif m % 2 == 0:\n\t\t\twhile j < m:\n\t\t\t\tj += 2\n\t\t\t\td_count += 1\n\t\telse:\n\t\t\twhile j <= m:\n\t\t\t\tj += 2\n\t\t\t\td_count += 1\n\t\t\td_count -= 1\n\telif m % 2 == 0:\n\t\ti = 0\n\t\td_count = 0\n\t\twhile i < m:\n\t\t\ti += 2\n\t\t\td_count += 1\n\t\td_count = d_count * n\n\telse:\n\t\tj = 0\n\t\td_count = 0\n\t\tif m % 2 == 0:\n\t\t\twhile j < m:\n\t\t\t\tj += 2\n\t\t\t\td_count += 1\n\t\telse:\n\t\t\twhile j <= m:\n\t\t\t\tj += 2\n\t\t\t\td_count += 1\n\t\td_count -= 1\n\t\td_count = d_count * n\n\t\ti = 0\n\t\tif n % 2 == 0:\n\t\t\twhile i < n:\n\t\t\t\ti += 2\n\t\t\t\td_count += 1\n\t\telse:\n\t\t\twhile i <= n:\n\t\t\t\ti += 2\n\t\t\t\td_count += 1\n\t\t\td_count = d_count - 1\n\tprint(d_count)\n","def solve():\n\t(M, N) = map(int, input().split())\n\tif M < 2 and N < 2:\n\t\tprint(0)\n\t\treturn\n\tif M < N:\n\t\t(M, N) = (N, M)\n\tres = N * (M // 2) + (N // 2 if M % 2 else 0)\n\tprint(res)\nsolve()\n","import math as mat\n(m, n) = map(int, input().split())\nans = m * n\nif ans % 2 == 0:\n\tans = ans / 2\n\tprint(int(ans))\nelse:\n\tans = mat.ceil(ans / 2)\n\tans = ans - 1\n\tprint(ans)\n","(m, n) = str(input()).split(' ')\nm = int(m)\nn = int(n)\nprint(int(m * n / 2))\n","num = input()\nmylist = num.split(' ')\nm = mylist[0]\nn = mylist[1]\nif int(m) >= 1 and int(m) <= 16 and (int(n) >= 1) and (int(n) <= 16):\n\tdominos = int(m) * int(n)\n\tava = dominos // 2\n\tprint(ava)\n","(m, n) = [int(x) for x in input().split()]\nprint(n // 2 * m + m // 2 * (n % 2 != 0))\n","(m, n) = list(map(int, input().split()))\narea_domino = 2\narea_sqr = m * n\nprint(area_sqr // area_domino)\n","(m, n) = map(int, input().split(' '))\nrect = m * n\ndom = rect // 2\nprint(dom)\n","(m, n) = [int(i) for i in input().split()]\ntotalSpace = m * n\nnumofDominos = totalSpace // 2\nprint(numofDominos)\n","p = [int(x) for x in input().split(' ')]\nk = p[0] * p[1]\na = int(k / 2)\nprint(a)\n","import math\nn = input().split(' ')\nprint(math.floor(int(n[0]) * int(n[1]) / 2))\n","num = input('').split()\na = int(num[0])\nb = int(num[1])\narea = a * b\nprint(area // 2)\n","def func():\n\t(m, n) = (int(i) for i in input().split())\n\tif m * n % 2:\n\t\tprint((m * n - 1) // 2)\n\telse:\n\t\tprint(m * n // 2)\nfunc()\n","l = input().split()\nx = int(l[0]) * int(l[1])\nprint(x // 2)\n","A = input()\nA = A.split()\nprint(int(A[0]) * int(A[1]) // 2)\n","(a, b) = [int(a) for a in input().split()]\narea = a * b\nprint(area // 2)\n","(m, n) = [int(x) for x in input().split()]\nc = m * n // 2\nprint(c)\n","import math\n(n, m) = [int(x) for x in input().split()]\nl = max(n, m)\nw = min(n, m)\nif l / 2 == l // 2:\n\tnum = l / 2 * w\nelse:\n\tnum = math.floor(l / 2) * w + math.floor(w / 2)\nprint(int(num))\n","tile_size = 2\nfield_size = tuple(map(int, input().split(' ')))\nresult = field_size[0] // tile_size * field_size[1] if not field_size[0] % tile_size else field_size[0] // tile_size * field_size[1] + field_size[1] // tile_size\nprint(result)\n","import math\n(m, n) = map(int, input().split())\ncount = 0\nwhile m > 1:\n\tcount += n\n\tm -= 2\nif m == 1:\n\tcount += math.floor(n / 2)\nprint(count)\n","import math as m\nx = list(map(int, input().split()))\ny = x[0] * x[1]\nt = m.floor(y / 2)\nprint(t)\n","(m, n) = map(int, input().split())\na = m * n\nb = a % 2\nif b == 0:\n\ti = a / 2\nelse:\n\tc = a - 1\n\ti = c / 2\np = int(i)\nprint(p)\n","list_ = [int(x) for x in input().split(' ')]\nm = list_[0]\nn = list_[1]\nprint(int(m * n / 2))\n","inp = input().split()\n(n, m) = (int(inp[0]), int(inp[1]))\nif n == 1 and m == 1:\n\tprint(0)\n\texit(0)\nans = max(n // 2 * m + (n - n // 2 * 2) * (m // 2), m // 2 * n + (m - m // 2 * 2) * (n // 2))\nprint(ans)\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\ty = m // 2\n\tprint(y * n)\nelse:\n\ty = m // 2\n\tt = y * n\n\tr = n // 2\n\tprint(t + r)\n","from array import *\nints = input('').split(' ')\nfor i in range(len(ints)):\n\tints[i] = int(ints[i])\n(m, n) = (ints[0], ints[1])\nfittable = 0\nT = [[0 for x in range(m)] for y in range(n)]\nfor i in range(len(T)):\n\tcount = 0\n\tfor j in range(len(T[i])):\n\t\tcount += 1\n\t\tif count >= 2:\n\t\t\tfittable += 1\n\t\t\tcount = 0\nif m % 2 != 0:\n\tif n % 2 != 0:\n\t\tfittable += (n - 1) / 2\n\telse:\n\t\tfittable += n / 2\nprint(int(fittable))\n","user_input = input()\nm = int(user_input.split()[0])\nn = int(user_input.split()[1])\nrectangles = m * n // 2\nprint(rectangles)\n","import sys\n\ndef max_num_dominoes(m, n):\n\tp = m * n\n\tif p % 2 == 0:\n\t\treturn p // 2\n\telse:\n\t\treturn m * (n - 1) // 2 + (m - 1) // 2\n\ndef main(args):\n\tlines = sys.stdin.readlines()\n\tm_n = map(int, lines[0].split())\n\tm = next(m_n)\n\tn = next(m_n)\n\tprint(max_num_dominoes(m, n))\nmain(sys.argv)\n","(m, n) = map(int, input().split())\ncuadrados = m * n\nfichas = cuadrados // 2\nprint(fichas)\n","(M, N) = map(int, input().split())\nans = M * N // 2\nprint(str(ans))\n","data = input().split(' ')\nm = int(data[0])\nn = int(data[1])\nif m >= 1 and m <= n and (n >= m) and (n <= 16):\n\tboard = m * n\n\tprint(str(int(board / 2)))\n","import sys, functools, operator\nprint(functools.reduce(operator.mul, [int(i) for i in sys.stdin.readline().split()]) // 2)\n","def putDomino():\n\ttableParams = [int(parameter) for parameter in input().split()]\n\tdominoMax = countNumDomino(tableParams)\n\tprintToConsole(dominoMax)\n\ndef countNumDomino(tableParams):\n\ttableLength = tableParams[0]\n\ttableWidth = tableParams[1]\n\ttableSize = tableLength * tableWidth\n\tdominoMax = tableSize // 2\n\treturn dominoMax\n\ndef printToConsole(dominoMax):\n\tprint(dominoMax)\nputDomino()\n","[n, m] = input().split(' ')\nsize = int(n) * int(m)\nprint(int(size / 2))\n","from math import floor\ns = input()\na = s.find(' ')\nm = int(s[:a])\nn = int(s[a + 1:])\nprint(floor(m * n / 2))\n","x = [int(i) for i in input().split()]\nprint(x[0] * x[1] // 2)\n","line = input().split()\n(M, N) = (int(line[0]), int(line[1]))\nprint(int(M * N / 2))\n","i = input()\nnumber = i.split()\nM = int(number[0])\nN = int(number[1])\nif (M > 0 and M < 17) and (N > 0 and N < 17):\n\tprint(int(M * N / 2))\n","from sys import stdin\nnums = [int(x) for x in stdin.readline().strip().split()]\nprint(nums[0] * nums[1] // 2)\n","(M, N) = map(int, input().split())\nL = M * N\nif L % 2 == 0:\n\tprint(int(L / 2))\nif L % 2 == 1:\n\tprint(int((L - 1) / 2))\n","sum = 0\ncount = 0\n(m, n) = input('').split()\nfor i in range(int(m)):\n\tfor j in range(int(n)):\n\t\tcount += 1\n\t\tif count == 2:\n\t\t\tsum += 1\n\t\t\tcount = 0\nprint(sum)\n","(M, N) = map(int, input().split())\nI = M * N // 2\nprint(I)\n","import math\na = input().split()\nl = int(a[0])\nd = int(a[1])\nif d == 1:\n\tprint(int(math.floor(l / 2)))\nelif d % 2 == 0:\n\tprint(int(l * d / 2))\nelse:\n\tprint(int(l * (d - 1) / 2 + math.floor(l / 2)))\n","(m, n) = [int(x) for x in input().split()]\nc1 = m * (n // 2) + n % 2 * (m // 2)\nc2 = n * (m // 2) + m % 2 * (n // 2)\nprint(int(max(c1, c2)))\n","inp = input().split()\nM = int(inp[0])\nN = int(inp[1])\nif M == 2 or N == 2:\n\tdom = M if N == 2 else N\n\tprint(dom)\nelse:\n\tM_2 = M if M % 2 == 0 else M - 1\n\tN_2 = N if N % 2 == 0 else N - 1\n\tx = M_2 if M_2 == N_2 else min(M_2, N_2)\n\tdom = int(M_2 / 2) * N_2\n\tif M % 2 != 0 and N % 2 == 0:\n\t\tdom = dom + int(N / 2)\n\telif M % 2 != 0 and N % 2 != 0:\n\t\tdom = dom + int((M + N - 1) / 2)\n\telif N % 2 != 0 and M % 2 == 0:\n\t\tdom = dom + int(M / 2)\n\tprint(dom)\n","a = input()\nlista = [int(i) for i in a.split()]\ntotal = lista[0] * lista[1]\ndom = total // 2\nprint(dom)\n","import math\n(m, n) = map(int, input().split())\na = math.floor(m / 2)\nb = math.floor(n / 2)\nc = math.ceil(m - 2 * a)\nd = math.ceil(n - 2 * b)\nt = 2 * a * b + c * b + d * a\nprint(t)\n","(n, m) = map(int, input().split())\nc = n // 2\nk = m\ne = 0\nif n % 2 == 1:\n\te += m // 2\nprint(c * k + e)\n","s = input()\na = s.split(' ')\nm = int(a[0])\nn = int(a[1])\nif n % 2 == 0 or m % 2 == 0:\n\tk = m * n // 2\nelse:\n\tp = divmod(m, 2)\n\tx = p[0]\n\tq = divmod(n, 2)\n\ty = q[0]\n\tk = n * x + y\nprint(k)\n","(M, N) = map(int, input().split())\nif M % 2 == 0:\n\tnum = M * N // 2\nelif N % 2 == 0:\n\tnum = M * N // 2\nelse:\n\tnum = M * (N - 1) // 2 + (M - 1) // 2\nprint(num)\n","rec = input().split()\nM = int(rec[0])\nN = int(rec[1])\nif M < N:\n\t(M, N) = (N, M)\nnum = M // 2 * N + M % 2 * (N // 2)\nprint(num)\n","b = input().split(' ')\nb = list(map(int, b))\nprint(int(b[0] * b[1] / 2))\n","input_data = input()\nlist_we_use = input_data.split(' ')\nb = []\nfor i in list_we_use:\n\tb.append(int(i))\nk = b[0] * b[1] / 2\nprint(int(k))\n","import math\n(m, n) = [int(s) for s in input().split()]\na = 2\nq = m * n / a\nq = math.floor(q)\nprint(q)\n","import sys\ninput = sys.stdin.readline\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef insr():\n\ts = input()\n\treturn list(s[:len(s) - 1])\n\ndef invr():\n\treturn map(int, input().split())\nboard = inlt()\nboardSize = board[0] * board[1]\nprint(int((boardSize - boardSize % 2) / 2))\n","e = list(input() + ' ')\nc = 0\nd = ' '\nn = ''\nm = ''\nb = 0\nwhile b == 0:\n\tif e[c] == d:\n\t\tb = 1\n\telse:\n\t\tn = n + e[c]\n\tc = c + 1\nwhile b == 1:\n\tif e[c] == d:\n\t\tb = 2\n\telse:\n\t\tm = m + e[c]\n\tc = c + 1\nn = int(n)\nm = int(m)\nprint(n * m // 2)\n","def main():\n\t(n, m) = [int(v) for v in input().split()]\n\tprint(n * m // 2)\nmain()\n","domino = 2\nboard = input().split()\nfor i in range(len(board)):\n\tboard[i] = int(board[i])\nM = board[0]\nN = board[1]\narea = M * N\nprint(area // 2)\n","from math import ceil\nq = input().split()\nprint(int(int(q[0]) * int(q[1]) / 2))\n","(m, n) = [int(i) for i in input().strip().split(' ')]\nprint(m * n // 2)\n","numbers = input().split()\nn1 = int(numbers[0])\nn2 = int(numbers[1])\nprint(int(n1 * n2 / 2))\n","from math import floor\n(m, n) = map(int, input().split())\nx = m * n / 2\nz = floor(x)\nprint(z)\n","(n, m) = map(int, input().split())\nif m % 2 == 0:\n\tprint(n * (m // 2))\nelif n % 2 == 0:\n\tprint(m * (n // 2))\nelse:\n\tx = n * (m // 2) + n // 2\n\ty = m * (n // 2) + m // 2\n\tprint(max(x, y))\n","def maxDominos(m, n):\n\tx = m * n\n\tif x % 2 == 0:\n\t\tdomino = x / 2\n\telse:\n\t\tdomino = (x - 1) / 2\n\treturn int(domino)\n(m, n) = map(int, input().split())\nprint(maxDominos(m, n))\n","list1 = input().split()\narea = int(list1[0]) * int(list1[1])\nprint(int(area / 2))\n","mn = list(map(int, input().split()))\nm = mn[0]\nn = mn[1]\ntot = 0\nif m >= 2:\n\ttot = m // 2\n\tif m % 2 == 0:\n\t\tprint(tot * n)\n\telse:\n\t\tprint(tot * n + n // 2)\nelif n >= 2:\n\ttot = n // 2\n\tif n % 2 == 0:\n\t\tprint(tot * m)\n\telse:\n\t\tprint(tot * m + m // 2)\nelif m < 2 and n < 2:\n\tprint('0')\n","import math\n(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nif m > 1 or n > 1:\n\tmx = math.floor(m / 2)\n\tm -= mx * 2\n\tres = mx * n\n\tif m > 0:\n\t\tres += math.floor(n / 2)\n\tprint(res)\nelse:\n\tprint('0')\n","(a, b) = list(map(int, input().split()))\nif a * b % 2 == 0:\n\tprint(int(a * b / 2))\nif a * b % 2 != 0:\n\tprint(int((a * b - a * b % 2) / 2))\n","s = input()\ns = s.split(' ')\nl = int(s[0])\nw = int(s[1])\nif l % 2 == 0:\n\ta = l * w // 2\nelif w % 2 == 0:\n\ta = l * w // 2\nelse:\n\ta = l * w // 2\nprint(a)\n","(m, n) = list(map(int, input().rstrip().split()))\ndominoes = m * n // 2\nprint(dominoes)\n","i = input()\nli = list(i.split(' '))\na = int(li[0])\nb = int(li[1])\nprint(int(a) * int(b) // 2)\n","import random\nd = input().split(' ')\nwidth = int(d[0])\nheight = int(d[1])\nmatrix = []\nfor i in range(height):\n\tmatrix.append([])\nfor row in matrix:\n\tfor cell in range(width):\n\t\trow.append({'flag': False})\nconsumed_flags = set()\nfor i in range(height):\n\tfor r in range(width):\n\t\tflag = random.randint(0, 2 ** 32)\n\t\tif not matrix[i][r].get('flag'):\n\t\t\tmatrix[i][r]['flag'] = flag\n\t\t\ttry:\n\t\t\t\tif flag not in consumed_flags:\n\t\t\t\t\tnext_cell_in_row = r + 1 < width\n\t\t\t\t\tnext_cell_in_col = i + 1 < height\n\t\t\t\t\tif next_cell_in_row and (not matrix[i][r + 1].get('flag', 0)):\n\t\t\t\t\t\tmatrix[i][r + 1]['flag'] = flag\n\t\t\t\t\t\tconsumed_flags.add(flag)\n\t\t\t\t\telif next_cell_in_col and (not matrix[i + 1][r].get('flag', 0)):\n\t\t\t\t\t\tmatrix[i + 1][r]['flag'] = flag\n\t\t\t\t\t\tconsumed_flags.add(flag)\n\t\t\texcept IndexError as exc:\n\t\t\t\tcontinue\nprint(len(consumed_flags))\n","def domino():\n\t(m, n) = map(int, input().split())\n\treturn m * n // 2\nprint(domino())\n","x = input()\ntarget = 1\nm = ''\nn = ''\nfor letter in x:\n\tif letter == ' ':\n\t\ttarget += 1\n\telse:\n\t\tif target == 1:\n\t\t\tm += letter\n\t\tif target == 2:\n\t\t\tn += letter\nm = int(m)\nn = int(n)\nmfix = False\nnfix = False\nif m / 2 != float(int(m / 2)):\n\tmfix = True\nif n / 2 != float(int(n / 2)):\n\tnfix = True\ntotal = 0\nm1 = m - 1\nn1 = n - 1\nif mfix == True:\n\tif nfix == True:\n\t\ttotal += m1 * int(n / 2)\n\t\ttotal += int(m / 2)\n\t\ttotal += int(n / 2)\n\telse:\n\t\ttotal += m * int(n / 2)\nelse:\n\ttotal += n * int(m / 2)\nprint(total)\n","(M, N) = map(int, input().split())\nbox = M * N\nprint(box // 2)\n","(n, m) = map(int, input().split())\ns = n * m\nx = s // 2\nprint(x)\n","(m, n) = map(int, input().split())\nnum = m * n\nif num % 2 == 1:\n\tx = (num - 1) / 2\nif num % 2 == 0:\n\tx = num / 2\nprint(int(x))\n","(a, b) = map(int, input().strip().split()[:2])\nr = a * b // 2\nprint(r)\n","(m, n) = [int(i) for i in input().split()]\nres = m * n // 2\nprint(res)\n","board = [int(num) for num in input().split(' ')]\n\ndef calculateSquaresWhenEven(num1, num2):\n\treturn num1 * num2 / 2\nif board[0] % 2 == 0 and board[1] % 2 == 0:\n\tprint(int(calculateSquaresWhenEven(board[0], board[1])))\nelif board[0] % 2 != 0 and board[1] % 2 != 0:\n\tSecureSquare = calculateSquaresWhenEven(board[0] - 1, board[1] - 1)\n\trestOfBoard = (board[0] - 1) / 2 + (board[1] - 1) / 2\n\tprint(int(SecureSquare + restOfBoard))\nelse:\n\tif board[0] % 2 != 0:\n\t\tSecureSquare = calculateSquaresWhenEven(board[0] - 1, board[1])\n\t\trestOfBoard = board[1] / 2\n\telse:\n\t\tSecureSquare = calculateSquaresWhenEven(board[0], board[1] - 1)\n\t\trestOfBoard = board[0] / 2\n\tprint(int(SecureSquare + restOfBoard))\n","size = list(map(int, input().split()))\nrows = size[0]\ncols = size[1]\ndominos = 0\nif rows % 2 == 0:\n\twhile rows > 1:\n\t\trows -= 2\n\t\tdominos += cols\nelse:\n\twhile rows > 1:\n\t\trows -= 2\n\t\tdominos += cols\n\twhile cols > 1:\n\t\tcols -= 2\n\t\tdominos += 1\nprint(dominos)\n","(m, n) = map(int, input().split())\nq1 = n // 2 * m\nif n % 2 == 1:\n\tq1 += m // 2\nprint(q1)\n","from sys import stdin, stdout\n\ndef trace(f):\n\n\tdef traced(*args, **kw):\n\t\tprint('calling {} with args {}, {}'.format(f.__name__, args, kw))\n\t\treturn f(*args, **kw)\n\treturn traced\n\n@trace\ndef f(x):\n\tprint(x)\n\ndef read():\n\treturn stdin.readline()[:-1]\n\ndef readarr(sep=None, maxsplit=-1):\n\treturn read().split(sep, maxsplit)\n\ndef readint():\n\treturn int(read())\n\ndef readintarr(sep=None, maxsplit=-1):\n\treturn [int(a) for a in readarr(sep, maxsplit)]\n\ndef write(*args, **kwargs):\n\tsep = kwargs.get('sep', ' ')\n\tend = kwargs.get('end', '\\n')\n\tstdout.write(sep.join((str(a) for a in args)) + end)\n\ndef writearr(arr, sep=' ', end='\\n'):\n\tstdout.write(sep.join((str(a) for a in arr)) + end)\n(M, N) = readintarr()\nmx = max(M, N)\nmn = min(M, N)\nr = int(mx / 2 * mn)\nwrite(r)\n","(n, k) = [int(x) for x in input().split()]\nprint(n * k // 2)\n","x = input()\nx = [i for i in map(int, x.split(' '))]\nsc = x[0] * x[1]\nprint(sc // 2)\n","i = lambda : map(int, input().split())\n(m, n) = i()\nif m % 2 == 1:\n\tx = (n * (m - 1) + n) / 2\nelse:\n\tx = m * n / 2\nz = abs(x)\nif z == x:\n\tprint(int(z))\nelse:\n\tprint(int(z + 1))\n","numbers = input()\nnumber = numbers.split(' ')\nprint(int(int(number[0]) * int(number[1]) / 2))\n","MN = input().split()\nM = int(MN[0])\nN = int(MN[1])\nif M * N % 2 == 0:\n\toutput = int(M * N / 2)\nelse:\n\toutput = int((M * N - 1) / 2)\nprint(output)\n","(n, m) = map(int, input().split())\nif n <= m <= 16:\n\tprint(m * n // 2)\n","user_input = str(input())\nif len(user_input) == 3:\n\tM = int(user_input[0])\n\tN = int(user_input[2])\nelif len(user_input) == 4:\n\tM = int(user_input[0])\n\tN = int(user_input[2:4])\nelse:\n\tM = int(user_input[0:2])\n\tN = int(user_input[3:5])\nif M >= 1 and N <= 16 and (N >= M):\n\tanswer = M * N // 2\n\tprint(answer)\n","import math\n(a, b) = input().split()\na = int(a)\nb = int(b)\ns = a * b\nk = math.floor(s / 2)\nprint(k)\n","input_str = str(input())\nl = input_str.split(' ')\nn = int(l[0])\nm = int(l[1])\na = 2\nresult = 0\nif n * m == a:\n\tresult = 1\nelif n == 1:\n\tresult = m // a\nelif m == 1:\n\tresult = n // a\nelse:\n\tresult = n * m // a\nprint(result)\n","(m, n) = list(map(int, input().split()))\nif m % 2 == 0 and n % 2 == 0:\n\tsum = m * n / 2\nelif m % 2 != 0 and n % 2 != 0:\n\tsum = m * n // 2\nelse:\n\tsum = m * n / 2\nprint(int(sum))\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nr = m * n\nprint(r // 2)\n","(M, N) = [int(x) for x in input().split(' ')]\nif M in range(0, 17) and N in range(0, 17):\n\tA = int(M * N / 2)\n\tprint(A)\n","(m, n) = map(int, input().split())\narea = m * n\noutput = area // 2\nprint(output)\n","def cal(n, m):\n\treturn (n * m - n * m % 2) // 2\na = list(map(int, input().split()))\nprint(cal(a[0], a[1]))\n","(A, B) = map(int, input().split())\nprint(A * B // 2)\n","(n, m) = map(int, input().split())\nb = n * m\nr = b // 2\nprint(r)\n","x = input().split()\nfor a in range(len(x)):\n\tx[a] = int(x[a])\nb = x[0] * x[1]\nb = int(b / 2)\nprint(b)\n","(m_height, n_length) = list(map(int, input().split()))\nif m_height < 1 or m_height > n_length or n_length > 16:\n\tprint('Wrong input')\n\texit()\ncount_dominos = 0\nis_vertical = False\nfor row in range(m_height):\n\ttemp_n = n_length\n\twhile True:\n\t\tif temp_n - 2 >= 0:\n\t\t\ttemp_n -= 2\n\t\t\tcount_dominos += 1\n\t\telif temp_n - 2 == -1 and m_height - row >= 2 and (not is_vertical):\n\t\t\ttemp_n -= 2\n\t\t\tcount_dominos += 1\n\t\t\tis_vertical = True\n\t\t\tbreak\n\t\telif temp_n - 2 == -1 and is_vertical:\n\t\t\ttemp_n -= 2\n\t\t\tis_vertical = False\n\t\t\tbreak\n\t\telse:\n\t\t\tbreak\nprint(count_dominos)\n","s = [int(n) for n in input().split()]\nprint(s[0] * s[1] // 2)\n","(m, n) = map(int, input().split())\narea = m * n\nnp = area // 2\nprint(np)\n","(panjang, lebar) = map(int, input().split())\nif panjang % 2 == 0:\n\tprint(panjang // 2 * lebar)\nelif lebar % 2 == 0:\n\tprint(lebar // 2 * panjang)\nelse:\n\tprint(panjang // 2 * lebar + lebar // 2)\n","sizes = list(map(int, input().split()))\nm = sizes[0]\nn = sizes[1]\nS = m * n\nres = S // 2\nprint(res)\n","n = [int(x) for x in input().split()]\na = n[0]\nb = n[1]\nprint(a * b // 2)\n","(n, m) = map(int, input().split())\nfin = n // 2 * m\nif n % 2 != 0:\n\tfin += m // 2\nprint(fin)\n","def solver(n, m):\n\treturn n * m // 2\n(n, m) = map(int, input().split())\nprint(solver(n, m))\n","def foo(x, y):\n\tprint(int(x * y / 2))\n(x, y) = input().split()\n(x, y) = [int(x), int(y)]\nfoo(x, y)\n","L = input().split(' ')\n(M, N) = (int(L[0]), int(L[1]))\nprint(M * N // 2)\n","desk_size = input().split(' ')\ndesk_square = int(desk_size[0]) * int(desk_size[1])\nprint(desk_square // 2)\n","import math\ns = str.split(input())\nM = int(s[0])\nN = int(s[1])\nif M % 2 == 0 or N % 2 == 0:\n\tprint(int(M * N / 2))\nelif M % 2 == 0:\n\tprint(int(M * (N - 1) / 2 + math.floor(M / 2)))\nelif N % 2 == 0:\n\tprint(int(N * (M - 1) / 2 + math.floor(N / 2)))\nelse:\n\tprint(int(M * (N - 1) / 2 + math.floor(M / 2)))\n","e = list(map(int, input().split()))\na = int(e[0]) * int(e[1])\nn = a // 2\nprint(n)\n","a = input().split()\nx = int(a[0])\ny = int(a[1])\nif x % 2 == 0 or y % 2 == 0:\n\tn = x * y / 2\nif x % 2 != 0 and y % 2 != 0:\n\tn = x * y // 2\nprint(int(n))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nt = m * n\nf = t // 2\nprint(f)\n","(r, j) = input().split()\nprint(int(r) * int(j) // 2)\n","(n, m) = map(int, input().split())\nc = 0\nif n >= 2:\n\tc += n // 2 * m\n\tif n % 2 != 0:\n\t\tc += m // 2\nelif m >= 2:\n\tc += m // 2 * n\n\tif m % 2 != 0:\n\t\tc += n // 2\nprint(c)\n","from math import ceil\nimport re\nentrada = input()\nmatch = re.search('(\\\\d*) (\\\\d*)', entrada)\nm = int(match.group(1))\nn = int(match.group(2))\nif m % 2 != 0 and n % 2 != 0:\n\tresultado = m * n // 2\nelse:\n\tresultado = m * n // 2\nprint(resultado)\n","n = list(map(int, input().split()))\na = n[0] * n[1]\nfor i in range(1, a + 1):\n\tm = i * 2\n\tif a == 1:\n\t\tprint(0)\n\t\tbreak\n\telif a == m:\n\t\tprint(i)\n\t\tbreak\n\telif a < m:\n\t\tprint(i - 1)\n\t\tbreak\n","data = input()\ndims = data.split(' ')\nm = int(dims[0])\nn = int(dims[1])\nprint(int(n * m / 2))\n","Dim = input().split()\nlmeo = int(Dim[0]) * int(Dim[1])\nanswer = lmeo // 2\nprint(int(answer))\n","(x, m) = map(int, input().split())\nprint(x * m // 2)\n","(x, y) = map(int, input().split())\nif x == 1 or y == 1:\n\tif x >= y:\n\t\tprint(x // 2)\n\telse:\n\t\tprint(y // 2)\nelse:\n\tprint(x * y // 2)\n","(m, n) = list(map(int, input().split()))\n(a, b) = (2, 1)\nif m % a != 0:\n\tmx = m // a\n\tmx = mx * n\n\tnx = n // 2\n\tx = mx + nx\nelse:\n\tmx = m // a\n\tx = mx * n\nprint(x)\n","(a, b) = map(int, input().split())\na = int(a * b)\nm = int(a / 2)\nprint(m)\n","import sys\nfirst_line = str(input()).split()\nm = int(first_line[0])\nn = int(first_line[1])\nif m + n < 2:\n\tprint(0)\nelse:\n\tprint(int(m * n / 2))\n","(m, n) = [int(x) for x in input().split()]\nif m <= n:\n\tA = m * n\n\tT = A // 2\nprint(T)\n","(M, N) = map(int, input().split())\nnum = M * N // 2\nprint(num)\n","(M, N) = input().split(' ')\nN = int(N)\nM = int(M)\n\ndef counter(m, n):\n\tif m == 1 and n == 1:\n\t\treturn 0\n\tif m == 1 and n % 2 == 0:\n\t\treturn int(n / 2)\n\tif m == 1 and n % 2 == 1:\n\t\treturn int((n - 1) / 2)\n\tif m % 2 == 0 and n % 2 == 0:\n\t\treturn int(m * n / 2)\n\tif m % 2 == 0 and n % 2 == 1:\n\t\treturn int(m * (n - 1) / 2) + counter(1, m)\n\tif m % 2 == 1:\n\t\treturn counter(1, n) + int((m - 1) * n / 2)\nprint(counter(M, N))\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nmatrix = n * m\nres = 0\nif matrix % 2 == 0:\n\tres = matrix // 2\nelse:\n\tres = matrix // 2\nprint(res)\n","import math\na = [int(x) for x in input().split()]\nb = a[0] * a[1]\nprint(math.floor(int(b / 2)))\n","from math import floor\n\ndef main(status=int(0)):\n\n\tdef solution():\n\t\t(m, n) = map(int, input().split())\n\t\tprint(max(floor(m / 2 * n), floor(n / 2 * m)))\n\tsolution()\n\treturn status\nmain()\n","(m, n) = map(int, input().split())\nres = 0\nif m < 2 and n < 1 or (m < 1 and n < 2):\n\tprint(0)\nelif m > n:\n\tres = m // 2 * n\n\tif m % 2 == 1:\n\t\tres += n // 2\nelse:\n\tres = n // 2 * m\n\tif n % 2 == 1:\n\t\tres += m // 2\nprint(res)\n","(t, k) = [int(i) for i in input().split()]\ns = t * k\nif s % 2 == 0:\n\tprint(s // 2)\nelse:\n\ts = s - 1\n\tprint(s // 2)\n","x = list(map(int, input().split()))\npro1 = x[0] * x[1]\nanf = pro1 // 2\nprint(anf)\n","rint = lambda : int(input())\nrmint = lambda : map(int, input().split())\nrlist = lambda : list(rmint())\n(n, m) = rmint()\nprint(n * m // 2)\n","import math\n(m, n) = input().split(' ')\nsumat = int(m) * int(n)\nprint(math.floor(sumat / 2))\n","(A, B) = map(int, input().split())\nif (A and B) >= 1 and (A and B) <= 16:\n\tS = A * B\n\tif S % 2 == 0:\n\t\tprint(int(S / 2))\n\tif S % 2 != 0:\n\t\tprint(S // 2)\n","import math\nimport os\nimport random\nimport re\nimport sys\n\ndef solve():\n\t(m, n) = list(map(int, input().split()))\n\tarea = m * n\n\treturn math.floor(area / 2)\nresult = solve()\nprint(result)\n","(n, m) = map(lambda val: int(val), input().split())\nprint(n * m // 2)\n","n = input().split()\nn1 = int(n[0])\nn2 = int(n[1])\nx = n1 * n2\nif x % 2 == 0:\n\tf = int(x / 2)\nelse:\n\tf = int((x - 1) / 2)\nprint(f)\n","(m, n) = map(int, input().split(' '))\nans = 0\nif m > 1:\n\tremaining = m % 2\n\tans = n * (m // 2)\n\tif remaining == 1:\n\t\tans += n // 2\nelif n > 1:\n\tremaining = n % 2\n\tans = m * (n // 2)\n\tif remaining == 1:\n\t\tans += m // 2\nprint(ans)\n","(n, k) = [int(i) for i in input().split()]\nz = n * k // 2\nprint(z)\n","(m, n) = (int(i) for i in input().split())\nif min(m, n) % 2 == 0:\n\tresult = m * n // 2\nelse:\n\tresult = max(m, n) * (min(m, n) - 1) // 2 + max(m, n) // 2\nprint(result)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\na = m // 2\nr = m % 2\nif r == 0:\n\tnum = a * n\nelse:\n\tnum = a * n + n // 2\nprint(num)\n","(x, y) = input().split()\nn = int(x)\nm = int(y)\nif n % 2 == 0:\n\td = n // 2 * m\nelse:\n\td = n // 2 * m + m // 2\nprint(d)\n","(m, n) = map(int, input().split())\nc = 2\na = m * n\nprint(int(a // c))\n","s = input()\ns = s + ' '\nif s[1] == ' ':\n\tM = int(s[0])\n\tif s[3] == ' ':\n\t\tN = int(s[2])\n\telse:\n\t\tN = int(s[2] + s[3])\nelse:\n\tM = int(s[0] + s[1])\n\tif s[4] == ' ':\n\t\tN = int(s[3])\n\telse:\n\t\tN = int(s[3] + s[4])\nif M % 2 == 0 or N % 2 == 0:\n\ta = int(M * N / 2)\nelse:\n\ta = int((M * N - 1) / 2)\nprint(a)\n","(m, n) = map(int, input().split())\nif m >= 1 and n >= m and (n <= 16):\n\tif m >= 2:\n\t\trow = m // 2\n\t\tcol = n // 1\n\t\ttotal = row * col\n\t\tif m % 2 == 1:\n\t\t\ttotal = total + n // 2\n\t\tprint(total)\n\tif m < 2:\n\t\ttotal = n // 2\n\t\tprint(total)\n","list1 = list(map(int, input().split()))\nfinalval = 1\nfor x in list1:\n\tfinalval *= x\nprint(int(finalval / 2))\n","import sys\n\ndef max_count(n, m):\n\tif n % 2 == 0:\n\t\tres = n // 2 * m\n\telif m % 2 == 0:\n\t\tres = m // 2 * n\n\telse:\n\t\tres = n * (m - 1) // 2 + (n - 1) // 2\n\treturn res\ndata = list(map(int, sys.stdin.read().split()))\n(n, m) = data[0:2]\nprint(max_count(n, m))\n","domino_board_sizes = list((int(num) for num in input().split(' ')))\nprint(int(domino_board_sizes[0] * domino_board_sizes[1] / 2))\n","area = input()\nareaList = area.split(' ')\ntotalArea = int(areaList[0]) * int(areaList[1])\nprint(totalArea // 2)\n","def solve():\n\t(width, height) = str(input()).split()\n\t(width, height) = (int(width), int(height))\n\twide_box = width * height\n\twide_dom = 2 * 1\n\ttot_dom = int(wide_box / wide_dom)\n\tprint(tot_dom)\nsolve()\n","size = input()\nsize = size.split()\nfor i in range(len(size)):\n\tsize[i] = int(size[i])\nif size[0] % 2 == 0 and size[1] % 2 == 0:\n\tprint(size[0] // 2 * size[1])\nelif size[0] % 2 == 0 or size[1] % 2 == 0:\n\tif size[0] % 2 == 0:\n\t\tprint(size[0] // 2 * size[1])\n\telse:\n\t\tprint(size[1] // 2 * size[0])\nelse:\n\tprint(size[0] * size[1] // 2)\n","import math\n(n, m) = map(int, input().split())\nans = math.floor(n / 2) * m\nif n % 2 != 0:\n\tans += math.floor(m / 2)\nprint(ans)\n","from sys import stdin\n_input = stdin.readline\n_int = int\n\ndef solution():\n\t(n, m) = [_int(i) for i in _input().split()]\n\tif n == 1 and m == 1:\n\t\tprint(0)\n\telif n % 2 == 0 or m % 2 == 0:\n\t\tprint(n * m // 2)\n\telse:\n\t\tprint(((n - 1) * (m - 1) + (n - 1) + (m - 1)) // 2)\nsolution()\n","def dominos(m, n):\n\tif m % 2 == 0:\n\t\treturn n * (m / 2)\n\telif n % 2 == 0:\n\t\treturn m * (n / 2)\n\telse:\n\t\tif m == 1 and n == 1:\n\t\t\treturn 0\n\t\tif m == 1:\n\t\t\treturn n // 2\n\t\tif n == 1:\n\t\t\treturn m // 2\n\t\telse:\n\t\t\treturn (m - 1) / 2 * n + n // 2\nimport sys\nline = []\nfor l in sys.stdin:\n\tline.append(l.rstrip('\\n'))\n(m, n) = (int(line[0].split(' ')[0]), int(line[0].split(' ')[1]))\nprint(int(dominos(m, n)))\n","params = input().split(' ')\nprint(int(int(params[0]) * int(params[1]) / 2))\n","(n, m) = [int(s) for s in input().split()]\na = n * m\nprint(a // 2)\n","def dom(m, n):\n\tif m == 1 and n == 1:\n\t\treturn 0\n\telse:\n\t\ta1 = m * n\n\t\tres = int(a1 / 2)\n\t\treturn res\n(m, n) = map(int, input().split())\nprint(dom(m, n))\n","mn = input().split()\nm = int(mn[0])\nn = int(mn[1])\nop = 0\nif n > m:\n\ttemp = m\n\tm = n\n\tn = temp\nif m % 2 != 0 and n % 2 != 0:\n\tif n == 1:\n\t\top = (m - 1) / 2\n\telse:\n\t\top = (n - 1) / 2 * m + int(m / 2)\nelif m % 2 == 0:\n\top = m / 2 * n\nelse:\n\top = n / 2 * m\nprint(int(op))\n","def init(m, n):\n\tboard = []\n\tnew = []\n\tfor i in range(m):\n\t\tfor j in range(n):\n\t\t\tnew.append(0)\n\t\tboard.append(new)\n\t\tnew = []\n\treturn board\n\ndef calculate(board, m, n):\n\tfilled = 0\n\tfor i in range(m):\n\t\tfor j in range(n):\n\t\t\tif board[i][j] == 1:\n\t\t\t\tpass\n\t\t\telif j + 1 != n:\n\t\t\t\tif board[i][j + 1] == 0:\n\t\t\t\t\tboard[i][j] = 1\n\t\t\t\t\tboard[i][j + 1] = 1\n\t\t\t\t\tfilled += 1\n\t\t\telif i + 1 != m:\n\t\t\t\tif board[i + 1][j] == 0:\n\t\t\t\t\tboard[i][j] = 1\n\t\t\t\t\tboard[i + 1][j] = 1\n\t\t\t\t\tfilled += 1\n\treturn filled\n\ndef main():\n\tinputstring = input()\n\tm = int(inputstring.split()[0])\n\tn = int(inputstring.split()[1])\n\tboard = init(m, n)\n\tprint(calculate(board, m, n))\nmain()\n","userInput = input()\ninputs = userInput.split()\nm = int(inputs[0])\nn = int(inputs[1])\nans = 0\nif n % 2 == 0:\n\tans = n // 2 * m\nelse:\n\tans = n // 2 * m + m // 2\nprint(str(ans))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m * n % 2 == 0:\n\tamount = m * n / 2\nelse:\n\tamount = (m * n - 1) / 2\namount = int(amount)\nprint(amount)\n","(m, n) = map(int, input().split())\nans = m // 2 * n\nif m % 2 != 0:\n\tans += n // 2\nprint(ans)\n","import math\nnum = str(input())\nnum = [int(j) for j in num.split()]\nm = num[0]\nn = num[1]\nans = int(n * math.floor(m / 2))\nif m % 2 != 0:\n\tans = int(ans + math.floor(n / 2))\nprint(ans)\n","(M, N) = map(int, input().split())\nnum = 0\narea = M * N\nwhile area > 1:\n\tarea -= 2\n\tnum += 1\nprint(num)\n","(m, n) = list(map(int, input().split()))\nf = n * (m // 2) + n // 2 * (m % 2)\nprint(f)\n","str = input()\nstr = str.split(' ')\nM = int(str[0])\nN = int(str[1])\nprint(int(M * N) // 2)\n","import math\n(x, y) = [int(i) for i in input().split()]\nanswer = x * y / 2\nprint(math.floor(answer))\n","board_size = list(map(int, input().split()))\na = board_size[0]\nb = board_size[1]\nprint(int(a * b / 2))\n","(rows, columns) = map(int, input().split())\nrem1 = rows % 2\ndominos1 = rows // 2 * columns + rem1 * columns // 2\nrem1 = columns % 2\ndominos2 = columns // 2 * rows + rem1 * rows // 2\nif dominos1 > dominos2:\n\tprint(dominos1)\nelse:\n\tprint(dominos2)\n","l = input()\nli = l.split(' ')\nm = int(li[0])\nn = int(li[1])\nif m == 1:\n\tprint(int(n / 2))\nelif n == 1:\n\tprint(int(m / 2))\nelif m % 2 == 0 and m > 1:\n\tprint(int(m / 2 * n))\nelif n % 2 == 0 and m > 1:\n\tprint(int(n / 2 * m))\nelif m % 2 != 0 and n % 2 != 0 and (m > 1) and (n > 1):\n\tprint(int((int(n / 2) * 2 + 1) * int(m / 2) + int(n / 2)))\n","def solution(n, m, ans):\n\tif n * m < 2:\n\t\treturn ans\n\tif n >= m:\n\t\treturn solution(n - 2, m, ans + m)\n\telse:\n\t\treturn solution(n, m - 2, ans + n)\nnm = input().split(' ')\nn = int(nm[0])\nm = int(nm[1])\nans = solution(n, m, 0)\nprint(ans)\n","import sys\nimport math\nparameters = sys.stdin.readline().rstrip().split(' ')\nparam1 = int(parameters[0])\nparam2 = int(parameters[1])\nif param1 > param2:\n\twidth = param1\n\theight = param2\nelse:\n\twidth = param2\n\theight = param1\ndominosWide = width // 2\ntotalDominos = dominosWide * height\nif width % 2 == 1:\n\ttotalDominos += height // 2\nprint(totalDominos)\n","i = input()\ni = i.split(' ')\nm = int(i[0])\nn = int(i[1])\narea = m * n\ncount = 0\nif area % 2 != 0 and area != 0:\n\tarea -= 1\nprint(int(area / 2))\n","(a, b) = input().split()\nm = int(a)\nn = int(b)\nans = m * n / 2\nprint(int(ans))\n","mn = list(map(int, input().split()))\nM = mn[0]\nN = mn[1]\nif M > N:\n\tprint(int(M * N / 2))\nelse:\n\tprint(int(N * M / 2))\n","x = list(map(int, input().rstrip().split()))\nans = x[0] * x[1]\nprint(ans // 2)\n","(n, m) = map(int, input().split())\nif not n % 2:\n\tprint(m * (n // 2))\nelif not m % 2:\n\tprint(n * (m // 2))\nelse:\n\tprint(int(n / 2 * m))\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nanswer = m * n / 2\nanswer = int(answer)\nprint(answer)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\narea = a * b\nif area % 2 == 0:\n\tw = int(area / 2)\n\tprint(w)\nelse:\n\tarea -= 1\n\td = int(area / 2)\n\tprint(d)\n","l = input().split()\na = int(l[0])\nb = int(l[1])\nc = a * b\nprint(int(c // 2))\n","numbers = [int(d) for d in input().split(' ')]\nn = numbers[0]\nm = numbers[1]\nsize = n * m\nif n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tpart1 = m * (n - 1) / 2\n\tif m % 2 == 0:\n\t\tpart1 += m / 2\n\telse:\n\t\tpart1 += (m - 1) / 2\n\tprint(int(part1))\n","(x, y) = [int(x) for x in input().split()]\narea = x * y\na = area // 2\nprint(a)\n","(M, N) = map(int, input().split())\nif M % 2 == 0:\n\tprint(M // 2 * N)\nif M % 2 != 0:\n\tprint(M // 2 * N + N // 2)\n","(m, n) = map(int, input().split())\nif m % 2 == 0 or n % 2 == 0:\n\tnum = n * m * 0.5\nelse:\n\tnum = (n * m - 1) * 0.5\nprint(int(num))\n","L = input().split()\nm = int(L[0])\nn = int(L[1])\nprint(m * n // 2)\n","(m, n) = [int(k) for k in input().split()]\nprint(m * n // 2)\n","(l, b) = map(int, input().split())\ntotalSquare = l * b\nif totalSquare % 2 != 0:\n\ttotalSquare -= 1\nans = totalSquare / 2\nprint(round(ans))\n","product = 1\nx = list(map(int, input().split()))\nfor item in x:\n\tproduct = product * item\nprint(product // 2)\n","import copy\n(n, m) = list(map(int, input().split(' ')))\nans = n * m // 2\nprint(ans)\n","(l, s) = input().split(' ')\nl = int(l)\ns = int(s)\nmultiple = l * s\nprint(int(multiple / 2))\n","def dominoPiling(mn):\n\tprint(int(mn[0] * mn[1] / 2))\ndominoPiling(list(map(int, input().split())))\n","import sys\n(a, b) = map(int, sys.stdin.readline().split())\narea = a * b\nprint(area // 2)\n","def main():\n\t(m, n) = [int(i) for i in input().split()]\n\tcolumns = m // 2\n\tright_pad_empty = m % 2\n\trows = n\n\tnow = rows * columns\n\tif right_pad_empty:\n\t\tnow += rows // 2\n\tprint(now)\nmain()\n","board = input()\nboard_list = board.split()\narea = int(board_list[0]) * int(board_list[1])\ndomino_fit = int(area / 2)\nprint(domino_fit)\n","(m, n) = map(int, input().split())\ni = 0\nif m == 1 or n == 1:\n\tj = max(m, n)\n\tnumber = j // 2\nelif n % 2 != 0:\n\tnumber = m * (n // 2) + m // 2\nelse:\n\tnumber = m * (n // 2)\nprint(number)\n","(a, b) = (int(x) for x in input().split(' '))\nif a % 2 == 0:\n\ta = a / 2\n\tc = a * b\nelif b % 2 == 0:\n\tb = b / 2\n\tc = a * b\nelse:\n\tc = (a - 1) / 2 * b + (b - 1) / 2\nc = int(c)\nprint(c)\n","a = list(map(int, input().split()))\nc = a[0]\nm = a[1]\nv = c * m\nj = v // 2\nprint(j)\n","b = list(map(int, input().split()))\na = b[0] * b[1] / 2\nprint(str(int(a)))\n","import sys\n\ndef calc(n, m):\n\treturn n // 2 * m + n % 2 * (m // 2)\n(m, n) = map(int, sys.stdin.readline().split())\nprint(max(calc(n, m), calc(m, n)))\n","(n, m) = map(int, input().split())\nres = divmod(n * m, 2)\nprint(res[0])\n","l = list(input().split())\nsqa = int(l[0]) * int(l[1])\nsqa = sqa // 2\nprint(sqa)\n","(m, n) = map(int, input().split())\narea = m * n\ntiles = area // 2\nprint(tiles)\n","base_input = input()\nsize_input = base_input.split(' ')\nmax_dominos = int(int(size_input[0]) * int(size_input[1]) / 2)\nprint(max_dominos)\n","(n, k) = list(map(int, input().split()))\nprint(int(n * k / 2))\n","inputs = list(map(int, input().strip().split()))[:2]\nm = inputs[0]\nn = inputs[1]\no = 0\nwhile True:\n\tif m <= 0:\n\t\tbreak\n\telif m < 2:\n\t\to += int(n / 2)\n\t\tm -= 1\n\telse:\n\t\to += n\n\t\tm -= 2\nprint(o)\n","(M, N) = map(int, input().split())\narea = M * N\nans = 0\nif N % 2 == 0 and M % 2 == 0:\n\tans = area // 2\nelif N % 2 == 0 and M % 2 != 0 or (N % 2 != 0 and M % 2 == 0):\n\tans = area // 2\nelse:\n\tans = area // 2\nprint(ans)\n","class DominoPiling:\n\n\t@staticmethod\n\tdef solve(x, y):\n\t\tunit = 2 * 1\n\t\tif 1 <= x <= y <= 16:\n\t\t\treturn '%d' % (x * y / unit)\n\ndef main():\n\t(x, y) = list(map(int, input().split(' ')))\n\tdp = DominoPiling()\n\tprint(dp.solve(x, y))\nmain()\n","import sys\n\ndef domino_calc(m, n):\n\tarea = m * n\n\tif area % 2 == 0:\n\t\treturn area / 2\n\treturn (area - 1) / 2\ninputs = [int(x) for x in input().split()]\ndominos = domino_calc(inputs[0], inputs[1])\nprint('%d' % dominos)\n","(m, n) = map(int, input().split())\nx = 1\nwhile 2 * x <= m * n:\n\tx += 1\nprint(x - 1)\n","(M, N) = map(int, input().split())\nimport math\nif M % 2 == 1 and N % 2 == 1:\n\tprint(math.floor(M * N / 2))\nelse:\n\tprint(int(M * N / 2))\n","nm = list(map(int, input().split()))\nr = nm[0] * nm[1]\np = int(r / 2)\nprint(p)\n","x = input()\nx = x.split()\nm = int(x[0])\nn = int(x[1])\nres = m * (n // 2) + n % 2 * (m // 2)\nprint(res)\n","import os\nimport sys\ndebug = True\nif debug and os.path.exists('input.in'):\n\tinput = open('input.in', 'r').readline\nelse:\n\tdebug = False\n\tinput = sys.stdin.readline\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef insr():\n\ts = input()\n\treturn s[:len(s) - 1]\n\ndef invr():\n\treturn map(int, input().split())\ntest_count = 1\nif debug:\n\ttest_count = inp()\nfor t in range(test_count):\n\tif debug:\n\t\tprint('Test Case #', t + 1)\n\t(m, n) = invr()\n\tprint(m * n // 2)\n","from math import floor as f\n(m, n) = map(int, input().split())\nprint(f(m * n / 2))\n","from functools import reduce\nmaximal = reduce(lambda x, y: x * y, [int(x) for x in str(input()).split(' ')])\nprint(maximal // 2)\n","(m, n) = map(int, input().split())\nif 1 <= m <= 16 and 1 <= n <= 16:\n\tarear = m * n\n\tx = arear / 2\n\tprint(int(x))\n","(M, N) = map(int, input().split())\nArea_of_rect = M * N\nM_N_D = Area_of_rect // 2\nprint(M_N_D)\n","import math\nline = input().split()\nnum = int(line[0]) * int(line[1]) // 2\nprint(num)\n","import math\nlis = list(map(int, input().split()))\nm = lis[0]\nn = lis[1]\nres = math.floor(m / 2 * n)\nprint(res)\n","def sol(n, k):\n\tt = 2 * 1\n\tb = n * k\n\treturn b / t\n(n, k) = map(int, input().split(' '))\nprint(int(sol(n, k)))\n","import math\nline = input().split()\nM = int(line[0])\nN = int(line[1])\ntotal = math.floor(M / 2) * N + M % 2 * math.floor(N / 2)\nprint(total)\n","import math\nall = [int(i) for i in input().split()]\narea = all[0] * all[1]\nprint(math.floor(area / 2))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 1 and n % 2 == 1:\n\tc = (m * n - 1) // 2\nelse:\n\tc = m * n // 2\nprint(c)\n","buf = input().split(' ')\na = int(buf[0])\nb = int(buf[1])\nprint(a * b // 2)\n","(m, n) = map(int, input().split())\na = n // 2\nb = n % 2\np = b * m\nc = p // 2\nprint(a * m + c)\n","import math\n(a, b) = map(int, input().split())\nprint(math.floor(a * b * 0.5))\n","s = input()\nmn = s.split()\nm = int(mn[0])\nn = int(mn[1])\nans = int(m * n / 2)\nprint(ans)\n","def main():\n\t(M, N) = map(int, input().split(' '))\n\tn = M * N // 2\n\tprint(n)\nmain()\n","import sys\ninput = sys.stdin.readline\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\nimport math\nsize = inlt()\nm = size[0]\nn = size[1]\nprint(int(math.floor(n * m * 0.5)))\n","(m, n) = map(int, input().split())\nc = 0\nif m % 2 != 0:\n\tn_r = m - 1\nelse:\n\tn_r = m\nfor i in range(0, n_r, 2):\n\tc += 1\nc = c * n\nn_C = m - n_r\nc2 = 0\nif n % 2 != 0:\n\tn_c = n - 1\nelse:\n\tn_c = n\nfor i in range(0, n_c, 2):\n\tc2 += 1\nc = c + c2 * n_C\nprint(c)\n","s = input()\nn = [int(i) for i in s.split(' ')]\nn1 = min(n)\nn2 = max(n)\nc = n1 // 2 * n2\nif n1 % 2 == 1:\n\tc = c + n2 // 2\nprint(int(c))\n","(a, b) = map(int, input().split())\nif a / 2 == a // 2:\n\tanswer = a / 2 * b\nelif b / 2 == b // 2:\n\tanswer = (a - 1) // 2 * b + b // 2\nelse:\n\tanswer = (a - 1) // 2 * b + (b - 1) // 2\nanswer1 = int(answer)\nprint(answer1)\n","l = input().split()\nM = int(l[0])\nN = int(l[1])\nif M % 2 != 0 and N % 2 != 0:\n\tn = M * int(N / 2) + int(M / 2)\nelse:\n\tn = int(M * N / 2)\nprint(n)\n","import sys\n(n, m) = [int(x) for x in input().split(' ')]\nif n % 2 == 0:\n\tjavob = int(n / 2 * m)\nelse:\n\tjavob = int(n / 2) * m + int(m / 2)\nprint(javob)\n","def go(a, b):\n\treturn a * b // 2\n(a, b) = list(map(int, input().split(' ')))\nprint(go(a, b))\n","give = input()\na = give.split()\nM = int(a[0])\nN = int(a[1])\nif M * N % 2 == 0:\n\tprint(int(M * N / 2))\nelse:\n\tprint(int((M * N - 1) / 2))\n","(M, N) = [int(x) for x in input().split(' ', 1)]\nif M == 1:\n\tsum = N // 2\nelif M % 2 == 0:\n\tsum = N * M // 2\nelse:\n\tsum = N * (M // 2) + N // 2\nprint(sum)\n","x = input('')\nx = x.split()\nx = [int(i) for i in x]\nn = x[0]\nm = x[-1]\nextra = 0\nif m % 2 == 0:\n\tusex = m\n\tusey = n\nelse:\n\tusex = m - 1\n\tusey = n\n\tif n % 2 == 0:\n\t\textra += n\n\telse:\n\t\textra += n - 1\nprint(int((usex * usey + extra) / 2))\n","def main():\n\tstr = input().split()\n\tM = int(str[0])\n\tN = int(str[1])\n\tboard_size = M * N\n\tdomino_number = board_size // 2\n\tprint(domino_number)\nmain()\n","from math import floor\narr = list(map(int, input().strip().split()))\nl = 2\nb = 1\nle = 0\nbr = 0\nmaxa = max(arr)\nmina = min(arr)\nif maxa >= l:\n\tprint(floor(maxa * mina / l * b))\nelse:\n\tprint(0)\n","import math\n\ndef gcd(a, b):\n\tif a % b == 0:\n\t\treturn b\n\telse:\n\t\treturn gcd(b, a % b)\n\ndef main():\n\t(m, n) = map(int, input().split(' '))\n\tprint(math.floor(m * n / 2))\nmain()\n","import sys\n\ndef get_ints():\n\treturn list(map(int, sys.stdin.readline().strip().split()))\nArr = get_ints()\nprint(int(Arr[0] * Arr[1] / 2))\n","mn = list(map(int, input().split()))\nm = mn[0]\nn = mn[1]\narea = m * n\nb = area // 2\nprint(b)\n","(m, n) = [int(x) for x in input().split()]\na = m * n\nif a % 2 == 1:\n\tb = (a - 1) / 2\nelse:\n\tb = a / 2\nb = int(b)\nprint(str(b))\n","(m, n) = [int(i) for i in input().split()]\nv = m % 2\nw = n % 2\nif v == 0 and w == 0:\n\ts = m * (n // 2)\nelif v == 0:\n\ts = m * (n // 2) + m // 2\nelif w == 0:\n\ts = n * (m // 2) + n // 2\nelse:\n\ts = (m - 1) * (n // 2) + n // 2 + m // 2\nprint(s)\n","from math import floor\n(m, n) = map(int, input().split(' '))\nresult = floor(m * n / 2)\nprint(result)\n","(m, n) = map(int, input().split())\narea = m * n\nans = area // 2\nprint(ans)\n","(a, b) = [int(x) for x in input().split()]\nif a * b % 2 == 0:\n\tm = a * b / 2\nelse:\n\tm = (a * b - 1) / 2\nprint(int(m))\n","(a, b) = input().split()\na = int(a)\nb = int(b)\ns = b * a\notv = s // 2\nprint(otv)\n","(m, n) = map(int, input().split())\nv = m * n\nb = 0\nc = 0\nwhile v >= b:\n\tb = b + 2\n\tif b <= v:\n\t\tc = c + 1\nprint(c)\n","board = input()\nboardList = board.split(' ')\n(M, N) = (boardList[0], boardList[1])\ntotal_board_size = int(M) * int(N)\nif total_board_size % 2 == 0:\n\toutput = total_board_size / 2\nelse:\n\toutput = (total_board_size - 1) / 2\nprint(int(output))\n","var = input()\narea = int(var.split()[0]) * int(var.split()[1])\na = area % 2\nprint(int((area - a) / 2))\n","(n, m) = [int(x) for x in input().split()]\ns = n * m\nq = s // 2\nprint(q)\n","(m, n) = map(int, input().split())\ns = m * n\nr = 2 * 1\nif s % r == 0:\n\tprint(s // r)\nelse:\n\to = s // r\n\tprint(o)\n","input_string = input()\nM = int(input_string.split()[0])\nN = int(input_string.split()[1])\nprint(M * N // 2)\n","(n, m) = map(int, input().split(' '))\ntotal = n * m\ndominos = int(total / 2)\nprint(dominos)\n","import math\nimport sys\nfrom functools import reduce\nfrom operator import mul\ninf = sys.stdin\ntemp = inf.readline()\nsize = [int(i) for i in temp.split(' ')]\nproduct = reduce(mul, size, 1)\nprint(math.floor(product / 2))\n","nums = input().split()\nprint(int(int(nums[0]) * int(nums[1]) / 2))\n","a = input()\naa = [int(k) for k in a.split(' ')]\nploschad = aa[0] * aa[1]\nskolko = ploschad // 2\nprint(skolko)\n","stream = input().split(' ')\nm = int(stream[0])\nn = int(stream[1])\nprint(m * n // 2)\n","(n, m) = tuple([int(num) for num in input().split()])\nif n % 2 == 0 or m % 2 == 0:\n\tprint(n * m // 2)\nelse:\n\tprint(n * (m - 1) // 2 + n // 2)\n","string = input()\nm = int(string.split()[0])\nn = int(string.split()[1])\nif m * n % 2 == 1:\n\tprint(int(m * n / 2 - 0.5))\nelse:\n\tprint(int(m * n / 2))\n","h = tuple(map(int, input().split()))\nprint(h[0] * h[1] // 2)\n","m = input()\nm = m.split()\nprint(int(m[0]) * int(m[1]) // 2)\n","def input_int(sep=' '):\n\trst = [int(n) for n in input().split(sep) if n]\n\treturn rst\n(M, N) = input_int()\nif M == 1:\n\tprint(int(N / 2))\nelif M % 2 == 0:\n\tprint(int(M / 2) * N)\nelse:\n\tprint(int(M / 2) * N + int(N / 2))\n","n = list(map(int, input().split()))\nif n[0] == 1 and n[1] == 1:\n\tprint('0')\nelse:\n\ts = n[0] * n[1]\n\tm = 0\n\tfor i in range(s):\n\t\tk = s - 2\n\t\ts = k\n\t\tm = m + 1\n\t\tif s <= 1:\n\t\t\tprint(m)\n\t\t\tbreak\n","def ii():\n\treturn int(input())\n\ndef si():\n\treturn input()\n\ndef mi():\n\treturn map(int, input().split())\n\ndef li():\n\treturn list(mi())\n(n, m) = mi()\nif n == 1 and m == 1:\n\tprint('0')\nelif n == 1 and m == 2 or (m == 1 and n == 2):\n\tprint('1')\nelse:\n\tx = n // 2\n\tans = x * m\n\tif n % 2:\n\t\tans += m // 2\n\tprint(ans)\n","(n1, n2) = map(int, input().split())\nresult = n1 * n2\nprint(result // 2)\n","a = input()\nad = 2 * 1\nb = a.split()\nc = 0\nfor i in b:\n\tc = int(b[0]) * int(b[1])\nd = c // ad\nprint(d)\n","(m, n) = [int(i) for i in input().split()]\nx = m * n\nif x % 2 != 0:\n\tx = x - 1\n\ty = x / 2\n\tprint(int(y))\nelse:\n\ty = x / 2\n\tprint(int(y))\n","(m, n) = [int(x) for x in input('').split(' ')]\nproduct = m * n\nmax = product // 2\nprint(max)\n","(m, n) = map(int, input().split())\narea = m * n\nif area < 2:\n\tout = 0\nelif area == 2:\n\tout = 1\nelse:\n\tlower_bound = m // 2 * (n // 2)\n\tadditional_count = (m * n - lower_bound * 4) // 2\n\tout = lower_bound * 2 + additional_count\nprint(out)\n","inp = input()\n(m, n) = list(map(int, inp.split(' ')))\nsquare = n * m\nprint(square // 2)\n","from math import floor\n(m, n) = map(int, input().split())\ndominos = floor(n / 2) * m\nif n % 2:\n\tdominos += floor(m / 2)\nprint(dominos)\n","arr = list(map(int, input().strip().split()))\nm = arr[0] * arr[1]\nt = m // 2\nprint(t)\n","(m, n) = map(int, input().split())\nx = max(m, n)\ny = min(m, n)\nprint(x * (y // 2) + y % 2 * (x // 2))\n","(m, n) = map(int, input().split())\np = m * n\noutput = 0\nif p % 2 == 1:\n\toutput += (p - 1) // 2\nelse:\n\toutput += p // 2\nprint(output)\n","import math\nline = input()\n(m, n) = line.split()\nm = int(m)\nn = int(n)\nif m % 2 != 0:\n\ta = math.floor(m / 2) * n + math.floor(n / 2)\nelse:\n\ta = m * n / 2\nprint(int(a))\n","while True:\n\t(n, m) = map(int, input().split(' '))\n\tif n and m in range(1, 17):\n\t\tbreak\nprint(int(n * m / 2))\n","def domino_piling(m, n):\n\tif m % 2 == 1 and n % 2 == 1:\n\t\treturn (m * n - 1) // 2\n\telse:\n\t\treturn m * n // 2\n(m, n) = (int(x) for x in input().split(' '))\nprint(domino_piling(m, n))\n","n = input().split()\nn = list(map(int, n))\nprint(str(int(n[0] * n[1] / 2)))\n","n = input().split()\nn = [int(i) for i in n]\np = n[0] * n[1]\nprint(p // 2, end='')\n","(area, area2) = input().split()\narea = int(area)\narea2 = int(area2)\nfinal_area = area * area2\ndominos = 2\nused = final_area // dominos\nprint(used)\n","a = list(map(lambda x: int(x), input().split()))\nprint(a[0] * a[1] // 2)\n","import math\nnum = [int(x) for x in input().split()]\nif num[0] > num[1]:\n\t(l, h) = (num[0], num[1])\nelse:\n\t(l, h) = (num[1], num[0])\nif l % 2 == 0:\n\tprint(h * l // 2)\nelse:\n\tprint(h * (l // 2) + h // 2)\n","a = list(map(int, input().split()))\nans = a[0] * a[1]\nans = int(ans)\nif ans % 2 == 0:\n\tprint(int(ans / 2))\nelse:\n\tprint(int((ans - 1) / 2))\n","def count(m, n):\n\treturn int(m * n / 2)\n(m, n) = input().split()\nprint(count(int(m), int(n)))\n","def board(m, n):\n\tif m == 2:\n\t\treturn n\n\telif n == 2:\n\t\treturn m\n\telse:\n\t\treturn m * n // 2\n(m, n) = map(int, input().split())\nprint(board(m, n))\n","s = input('').split()\nm = int(s[0])\nn = int(s[1])\nmono = m * n\ndominoes = m * n // 2\nprint(dominoes)\n","def solve():\n\t(m, n) = list(map(int, input().split()))\n\tprint(m * n // 2)\n\ndef main():\n\tsolve()\nmain()\n","(l, m) = map(int, input().split(' '))\nfield = l * m\nif field % 2 != 0:\n\tfield -= 1\nprint(int(field / 2))\n","inp = input().split(' ')\nArea = int(inp[0]) * int(inp[1])\nnum = Area // 2\nprint(num)\n","(M, N) = map(int, input().split())\nrem = M * N % 2\nif rem == 0:\n\tprint(M * N // 2)\nelse:\n\tprint((M * N - rem) // 2)\n","L = input()\nL = L.split()\nM = int(L[0])\nN = int(L[1])\nT = N // 2\nP = M // 2\nif N % 2 == 0:\n\tR = T * M\nelse:\n\tR = T * M + P\nprint(R)\n","import sys\ninput = sys.stdin.readline\nnums = list(map(int, input().split()))\narea = nums[0] * nums[1]\nresult = int((area - area % 2) / 2)\nprint(result)\n","mn = list(map(int, input().split()))\nprint(mn[0] * mn[1] // 2)\n","def getDominoCount(width, height):\n\treturn width * height // 2\n(a, b) = map(int, input().split(' '))\nprint(getDominoCount(a, b))\n","sizes = [int(i) for i in input().split()]\nprint(int(sizes[0] * sizes[1] / 2))\n","line = input()\nM = int(line.split(' ')[0])\nN = int(line.split(' ')[1])\nsum = 0\nif M % 2 == 0:\n\tsum = int(M * N / 2)\nelse:\n\tM = M - 1\n\tsum = int(M * N / 2)\n\tsum = sum + int(N / 2)\nprint(sum)\n","(n, m) = map(int, input().split())\n\ndef fun():\n\ta = n * m\n\tb = n * m / 2\n\treturn int(b)\nprint(fun())\n","y = input()\ny = y.split()\nx = []\nfor i in range(0, len(y)):\n\tm = int(y[i])\n\tx.append(m)\nn = 1\nfor j in range(0, len(x)):\n\tn = n * x[j]\nn = n / 2\nprint(int(n))\n","t = list(map(int, input().split(' ')))\nm = t[0]\nn = t[1]\nresult = 0\nresult = n // 2 * m\nif n % 2 == 1:\n\tresult += m // 2\nprint(result)\n","areainput = input()\nx = areainput.split()\narea = int(x[0]) * int(x[1])\noutput = area // 2\nprint(output)\n","(M, N) = map(int, input().split())\nA = 0\nA = M / 2 * N\nprint(int(A))\n","area_input = input().split()\narea = int(area_input[0]) * int(area_input[1])\nif area % 2 == 0:\n\tprint(int(area / 2))\nelse:\n\tprint(int(area / 2 - 0.5))\n","MN = input()\nMN = MN.split()\nM = int(MN[0])\nN = int(MN[1])\nif M % 2 == 0 or N % 2 == 0:\n\ttotal = M * N / 2\nelse:\n\ttotal = (M - 1) * (N - 1) / 2\n\ttotal = total + (M + N - 1) / 2\nprint(int(total))\n","(M, N) = list(map(int, input().split()))\nCount = 0\nwhile N >= 2:\n\tCount += M\n\tN -= 2\nif N == 1:\n\tCount += int(M / 2)\nprint(Count)\n","import math\nline = input()\npieces = line.split()\na0 = int(pieces[0])\na1 = int(pieces[1])\nprint(int(a1 * a0 / 2))\n","import math\n(m, n) = input().split(' ')\n(m, n) = (int(m), int(n))\ntotal = m * n\ni = 0\nresult = 0\nfor i in range(9999):\n\tif 2 * i > total:\n\t\tresult = i - 1\n\t\tbreak\nprint(result)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nres = 0\nif m % 2 == 0 & n % 2 == 0:\n\tres = m / 2 * n\nif m % 2 != 0 & n % 2 == 0:\n\tres = n / 2 * m\nif m % 2 == 0 & n % 2 != 0:\n\tres = m / 2 * n\nif m % 2 != 0 & n % 2 != 0:\n\tres = (m * n - 1) / 2\nprint(int(res))\n","(a, b) = map(int, input().split(' '))\nsuma = 0\nr = a % 2\nt = a // 2\nt = t * b\nsuma += t\nif r == 1:\n\tsuma += b // 2\nprint(suma)\n","import math\nimport sys\ninp = list(map(int, input().split()))\nn = inp[0]\nm = inp[1]\nif n * m % 2 == 0:\n\tprint(round(n * m / 2))\nelse:\n\tprint(round((n * m - 1) / 2))\n","l = input()\nl = l.split()\na = int(l[0])\nb = int(l[1])\nx = int(a * b / 2)\nif a * b == 1:\n\tx = 0\nprint(x)\n","mn = tuple(map(int, input().split()))\nprint(int(mn[0] * mn[1] / 2))\n","(m, n) = input().split(' ')\nwidth = int(m)\nheight = int(n)\nisArea = width * height\nnumOfDomino = isArea // 2\nprint(numOfDomino)\n","(m, n) = map(int, input().split())\ntemp = 0\nprint(m * n // 2)\n","i = input().split(' ')\nif int(i[1]) % 2 == 0:\n\tprint(str(int(int(i[1]) / 2 * int(i[0]))))\nelse:\n\tprint(str(int((int(i[1]) - 1) / 2 * int(i[0]) + (int(i[0]) - int(i[0]) % 2) / 2)))\n","m_and_n = input().split()\nm = int(m_and_n[0])\nn = int(m_and_n[1])\ne = []\nprint(m * n // 2)\n","(n, m) = map(int, input().rstrip().split())\narea = n * m\nprint(n * m // 2)\n","info = input().split(' ')\nM = int(info[0])\nN = int(info[1])\nif M == N:\n\twidth = height = M\nelif M < N:\n\theight = M\n\twidth = N\nelse:\n\theight = N\n\twidth = M\nanswer = 0\nif height >= 2:\n\tanswer = height // 2 * width + height % 2 * (width // 2)\nelse:\n\tanswer = width // 2\nprint(answer)\n","(m, n) = [int(x) for x in input().split()]\ncount = n // 2\ncount *= m\nif n % 2 != 0:\n\tcount += m // 2\nprint(count)\n","s = list(map(int, input().split()))\nif s[0] % 2 == 0 or s[1] % 2 == 0:\n\tprint(s[0] * s[1] // 2)\nelse:\n\tprint((s[0] * s[1] - 1) // 2)\n","def input_int():\n\treturn int(input())\n\ndef input_str():\n\treturn str(input())\n\ndef get_result(a, b):\n\treturn int(a * b / 2)\n(a, b) = map(int, input().split())\nprint(get_result(a, b))\n","def main():\n\t(m, n) = input().split()\n\tm = int(m)\n\tn = int(n)\n\tk = m * n\n\tif k % 2 == 0:\n\t\ta = k / 2\n\t\ta = int(a)\n\t\tprint(a)\n\telse:\n\t\ta = (k - 1) / 2\n\t\ta = int(a)\n\t\tprint(a)\nmain()\n","a = [int(n) for n in input().split()]\nprint(a[0] * a[1] // 2)\n","(x, y) = [int(m) for m in input().split()]\narea = x * y\nprint(int(area / 2))\n","dimensions = input('')\ndimensions = [int(i) for i in dimensions.split(' ')]\narea = 1\nfor i in dimensions:\n\tarea *= i\nprint(area // 2)\n","siz_arr = list(map(int, input().rstrip().split()))\nm = siz_arr[0]\nn = siz_arr[1]\nroww = max(m, n)\ncoll = m + n - roww\nif coll % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(roww * int(coll / 2) + int(roww / 2)))\n","from sys import stdin\n(x, y) = stdin.readline().split(' ')\nprint(int(x) * int(y) // 2)\n","get = lambda : list(map(int, input().split()))\n(a, b) = get()\nprint(a * b // 2)\n","ips = input().split()\nM = int(ips[0])\nN = int(ips[1])\nprint(int(M * N / 2))\n","class domino:\n\n\tdef __init__(self):\n\t\tself.input_l = list(map(int, input().split()))\n\t\tself.solve()\n\n\tdef solve(self):\n\t\tself.m_x = self.input_l[0] * self.input_l[1]\n\t\tresult = self.m_x // 2\n\t\tprint(result)\nd = domino()\n","(m, n) = map(int, input().split())\ns = 0\nt = m * n\nif t % 2 == 1:\n\tt -= 1\nprint(t // 2)\n","a = input()\nmass = a.split()\nd1 = int(mass[0])\nd2 = int(mass[1])\nif d1 % 2 != 0 and d2 % 2 != 0:\n\tprint(d1 * d2 // 2)\nelse:\n\tprint(d1 * d2 // 2)\n","(m, n) = map(int, input().split())\nsq = 2\nvalue = int(m * n / sq)\nprint(value)\n","(x, y) = input().split()\nboardsize = int(x) * int(y)\nnumOfDoms = int(boardsize) // 2\nprint(numOfDoms)\n","dimensions = input().split(' ')\nm = int(dimensions[0])\nn = int(dimensions[1])\narea = m * n\nif area % 2 == 0:\n\tprint(area // 2)\nelse:\n\tprint((area - 1) // 2)\n","(m, n) = input().split(' ')\noutput = int(m) * int(n) // 2\nprint(output)\n","import math\nrectangleArray = input().split(' ')\narea = int(rectangleArray[0]) * int(rectangleArray[1])\nprint(math.floor(area / 2))\n","firstLine = input().split()\nm = int(firstLine[0])\nn = int(firstLine[1])\nanswer = int(m * n / 2)\nprint(answer)\n","(m, n) = map(int, input().split())\nif m >= 1 and m <= n and (n <= 16):\n\tb = m * n // 2\nprint(b)\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nsquare = m * n\nif square % 2 == 0:\n\tprint(int(square / 2))\nelse:\n\tprint(square // 2)\n","(n, m) = map(int, input().split())\ns1 = m // 2 * n + n * (m % 2) // 2\ns2 = n // 2 * m + m * (n % 2) // 2\nprint(max(s1, s2))\n","def dominoes(check):\n\treturn check // 2\n(m, n) = map(int, input().strip().split())\ncheck = m * n\nprint(dominoes(check))\n","(m, n) = map(int, input().split())\ntemp1 = m // 2\nsum = temp1 * n\ntemp2 = m % 2\nif temp2 == 1:\n\tsum += n // 2\nprint(sum)\n","def dominoPiling(M, N):\n\tif M * N % 2 == 0:\n\t\treturn M * N\n\telse:\n\t\treturn M * N - 1\nMN = input().split()\nM = int(MN[0])\nN = int(MN[1])\nres = dominoPiling(M, N)\nprint(int(res / 2))\n","import math\n(a, b) = map(int, input().split())\nc = math.floor(a * b / 2)\nprint(c)\n","def main():\n\t(s_edge, l_edge) = map(int, input().split())\n\tprint(s_edge * l_edge // 2)\nmain()\n","from math import ceil\n(m, n) = [int(i) for i in input().split()]\nx = m * n\ny = x // 2\nprint(y)\n","from math import floor\n(m, n) = map(int, input().split())\ndomino_size = 2\nmax_domino = floor(m * n / domino_size)\nprint(max_domino)\n","a = input()\nnum = [int(n) for n in a.split()]\nm = num[0]\nn = num[1]\nprint(m * n // 2)\n","(m, n) = [int(x) for x in input().split()]\ntotal = m * n\nif total % 2 == 0:\n\tprint(int(total / 2))\nelse:\n\tprint(int((total - 1) / 2))\n","(m, n) = map(int, input().split())\nspace = m * n\ncount = space // 2\nprint(count)\n","(a, b) = map(int, input().split())\nk = a * b // 2\nprint(k)\n","import sys\n(M, N) = map(int, sys.stdin.read().split())\nprint('%d' % (M * N / 2))\n","from sys import stdin\ninput = stdin.readline\n\ndef main():\n\t(m, n) = map(int, input().split())\n\tprint(m * n // 2)\nmain()\n","x = [int(i) for i in input().split()]\nn = x[0]\nm = x[1]\ns = n * m\ncount = s // 2\nprint(count)\n","x = input()\n(aa, bb) = x.split()\na = int(aa)\nb = int(bb)\nm = max(a, b)\nn = min(a, b)\nrow = m\ncol = int(n / 2)\nres = row * col\nrow = int(m / 2)\ncol = n\nres = max(res, row * col)\nresidual = a * b - res * 2\nres = res + int(residual / 2)\nprint(res)\n","line = input().split()\nm = int(line[0])\nn = int(line[1])\nnumber = 0\nif n % 2 == 0:\n\tnumber = n / 2 * m\nelse:\n\tmar = n // 2\n\tcountone = n // 2 * m\n\tif m % 2 == 0:\n\t\tmar_1 = m / 2\n\t\tcount = countone + mar_1\n\telse:\n\t\tmar_1 = m // 2\n\t\tcount = countone + mar_1\n\tnumber = count\nprint(int(number))\n","import sys\nnumbers = [int(i) for i in sys.stdin.readline().split()]\nM = numbers[0]\nN = numbers[1]\nif 1 <= M <= N <= 16:\n\tif M * N % 3 == 1 or M * N % 3 == 2:\n\t\tb = M * N / 2\n\t\tprint(int(b))\n\telse:\n\t\tb = M * N / 2\n\t\tprint(int(b))\n","l = list(input().split())\nm = int(l[0])\nn = int(l[1])\nif m % 2 == 0:\n\tprint(m // 2 * n)\nelif n % 2 == 0:\n\tprint(n // 2 * m)\nelse:\n\tprint(m // 2 * n + n // 2)\n","import math\n(M, N) = map(int, input().split())\ntotal_sq = M * N\ndomino_ar = 2 * 1\nprint(math.floor(total_sq / domino_ar))\n","(n, k) = input().split()\nn = int(n)\nk = int(k)\nif n * k % 2 == 0:\n\tprint(round(n * k / 2))\nelif n * k % 2 == 1:\n\tprint(round(n * k / 2 - 0.5))\n","(m, n) = map(int, input().split())\npovrsina = m * n\ndomino = 2\nprint(povrsina // domino)\n","import math\n(m, n) = map(int, input().split())\nans = max(m, n) * min(m, n) / 2\nprint(int(ans))\n","t = list(map(int, input().split()))\n(m, n) = (t[0], t[1])\nk = m * n // 2\nprint(k)\n","(x, y) = input().split()\n(q, w) = (int(x), int(y))\nit = q * w // 2\nprint(it)\n","masukan = input()\nmasukan2 = []\nfor i in masukan.split(' '):\n\tmasukan2 = masukan2 + [i]\nm = int(masukan2[0])\nn = int(masukan2[1])\nkeluaran = int(m * n / 2)\nprint(keluaran)\n","a = input().split()\nfor i in range(len(a)):\n\ta[i] = int(a[i])\nb = a[0] * a[1]\nc = b // 2\nprint(c)\n","n = input()\nn = n.split()\ntry:\n\tif 3 > len(n) > 1:\n\t\tm = int(n[0])\n\t\tn = int(n[1])\n\t\tprint(m * n // 2)\n\telse:\n\t\tprint('INVALID INPUTS')\nexcept:\n\tprint('INVALID INPUTS')\n","(m, n) = input('').split(' ')\na = int(m)\nb = int(n)\np = a * b\nprint(p // 2)\n","dim = input().split()\nspace = int(dim[0]) * int(dim[1])\npieces = int(space / 2)\nprint(pieces)\n","m_n = input()\ncont1 = ''\nfor i in m_n:\n\tif i.isdigit():\n\t\tcont1 += i\nif 1010 <= int(cont1) <= 1616:\n\tcont1new = cont1\n\tcont1 = cont1[:2]\n\tcont2 = cont1new[2:]\n\tresult = int(cont1) * int(cont2)\n\tmax_result = int(result) // 2\n\tprint(max_result)\nelif int(cont1) < 1010:\n\tcont1n = cont1\n\tcont3 = cont1[0]\n\tcont4 = cont1n[1:]\n\tresult = int(cont3) * int(cont4)\n\tmax_result = result // 2\n\tprint(max_result)\n","c = input()\nx = c.split(' ')\nv = []\nfor i in x:\n\tv.append(int(i))\nprint(v[0] * v[1] // 2)\n","(m, n) = input().split()\n(m, n) = (int(m), int(n))\ncounter = 0\nif m % 2 == 0:\n\tcounter += m / 2 * n\nelif n % 2 == 0:\n\tcounter += n / 2 * m\nelif n == 1:\n\tpass\nelif m > 1:\n\tcounter += (m - 1) / 2 * n\n\tcounter += (n - 1) / 2\nelse:\n\tcounter += (n - 1) / 2\nprint(int(counter))\n","lst = list(map(lambda x: int(x), input().split()))\nprint(lst[0] * lst[1] // 2)\n","k = list(map(int, input().split()))\nif k[0] * k[1] % 2 == 1:\n\tprint(int((k[0] * k[1] - 1) / 2))\nelse:\n\tprint(int(k[0] * k[1] / 2))\n","import math\nmn = list(map(int, input().split()))\nk = math.floor(mn[0] * mn[1] / 2)\nprint(k)\n","(l, w) = list(map(int, input().split(' ')))\narea = l * w\ndomino_area = 2 * 1\nprint(area // domino_area)\n","(f, y) = input().split()\nf = int(f)\ny = int(y)\na = int(f * y / 2)\nprint(a)\n","(x, y) = [int(x) for x in input('').split()]\nar = x * y\nprint(int(x * y / 2))\n","import math\nst = ''\n\ndef func(a, b):\n\treturn a * b // 2\nfor _ in range(1):\n\t(a, b) = map(int, input().split())\n\tst += str(func(a, b)) + '\\n'\nprint(st)\n","(m, n) = [int(s) for s in input().split()]\nkol = 0\nif m % 2 == 0 or n % 2 == 0:\n\tif m % 2 == 0:\n\t\tkol += m // 2\n\t\tkol *= n\n\telse:\n\t\tkol += n // 2\n\t\tkol *= m\nif m % 2 == 1 and n % 2 == 1:\n\tif m > n:\n\t\tkol += m // 2\n\t\tkol *= n\n\t\tkol += n // 2\n\telse:\n\t\tkol += n // 2\n\t\tkol *= m\n\t\tkol += m // 2\nprint(kol)\n","g = str(input()).split()\nm = int(g[0])\nn = int(g[1])\nif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m * n - 1) / 2))\n","b = input()\nlist1 = b.split(' ')\nM = int(list1[0])\nN = int(list1[1])\noutput = M * N // 2\nprint(output)\n","def max_dominoes():\n\t(m, n) = input().split()\n\t(m, n) = (int(m), int(n))\n\tif 1 <= m <= n <= 16:\n\t\tresult = m * n\n\t\treturn result // 2\nprint(max_dominoes())\n","entrada = input().split(' ')\nentrada = int(entrada[0]) * int(entrada[1])\nprint(entrada // 2)\n","from sys import stdin, stdout\nfrom math import floor\n(m, n) = list(map(int, stdin.readline().rstrip().split()))\nstdout.write(str(int(floor(m * n / 2))))\n","(n, m) = [int(x) for x in input().split()]\nif n % 2 == 0:\n\tf = n // 2 * m\nelif m % 2 == 0:\n\tf = n * (m // 2)\nelse:\n\tf = m * (n // 2) + m // 2\nprint(f)\n","rc = input().split()\nm = int(rc[0])\nn = int(rc[1])\nprint(int(m * n / 2))\n","entrada = input().split(' ')\nM = int(entrada[0])\nN = int(entrada[1])\nprint(int(M * N / 2))\n","from sys import stdin, stdout\ninp = stdin.readline\nout = stdout.write\n(M, N) = map(int, inp().strip().split())\nout(str(M * N // 2))\n","(R, C) = map(int, input().split())\nr = R * C\nif r % 2 == 0:\n\tprint(int(r / 2))\nelse:\n\tprint(int((r - 1) / 2))\n","import math\nx = list(map(int, input().split(' ')))\na = x[0]\nb = x[1]\nc = a * b\nif c / 2 == 0:\n\tprint(c / 2)\nelse:\n\tprint(math.floor(c / 2))\n","a = [int(i) for i in input().split()]\n(m, n) = (a[0], a[1])\nres = m * n\nif res % 2 == 0:\n\tprint(int(res / 2))\nelse:\n\tprint(int(res / 2))\n","(n, m) = [int(x) for x in input().split()]\nc = 0\nif n % 2 == 0 or m % 2 == 0:\n\tif n % 2 == 0:\n\t\tc = n // 2\n\t\tc = c * m\n\telse:\n\t\tc = m // 2\n\t\tc = c * n\nelse:\n\tn -= 1\n\tc = n // 2\n\tc = c * m\n\tc += (m - 1) // 2\nprint(c)\n","ii = input().split()\nprint(int(ii[0]) * int(ii[1]) // 2)\n","line = input()\nfirstNum = ''\nsecondNum = ''\nplaceholder = 0\nwhile line[placeholder] != ' ':\n\tfirstNum = firstNum + str(line[placeholder])\n\tplaceholder = placeholder + 1\nplaceholder = placeholder + 1\nwhile placeholder < len(line):\n\tsecondNum = secondNum + str(line[placeholder])\n\tplaceholder = placeholder + 1\ntotal = int(firstNum) * int(secondNum) / 2\nprint(int(total))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif 1 <= m <= n <= 16:\n\tarea = int(m) * int(n)\n\tsq = int(area / 2)\n\tprint(sq)\n","(m, n) = [int(x) for x in input().split()]\nif not m % 2:\n\tprint(int(m // 2 * n))\nelif not n % 2:\n\tprint(int(n // 2 * m))\nelse:\n\tprint(int((m - 1) // 2 * n + (n - 1) // 2))\n","(m, n) = list(map(int, input().split()))\nvisited = [[0 for j in range(n)] for i in range(m)]\ncount = 0\nfor i in range(m):\n\tfor j in range(n):\n\t\tif i >= 0 and i < m and (i + 1 >= 0) and (j >= 0) and (j < n) and (i + 1 < m) and (visited[i][j] == 0) and (visited[i + 1][j] == 0):\n\t\t\tvisited[i][j] = 1\n\t\t\tvisited[i + 1][j] = 1\n\t\t\tcount += 1\n\t\telif i >= 0 and i < m and (j >= 0) and (j + 1 < n) and (visited[i][j] == 0) and (visited[i][j + 1] == 0):\n\t\t\tvisited[i][j] = 1\n\t\t\tvisited[i][j + 1] = 1\n\t\t\tcount += 1\nprint(count)\n","a = list(map(int, input().split()))\nx = a[0] * a[1]\ny = 0\ni = 0\nj = 1\nwhile y < x - x % 2:\n\ty = y + 2\n\ti = i + 1\nprint(i)\n","import math\n\ndef main():\n\ti = input().split()\n\tm = int(i[0])\n\tn = int(i[1])\n\tif m == 1 and n == 1:\n\t\tprint(0)\n\telif m == 1:\n\t\tprint(math.floor(n / 2))\n\telif n == 1:\n\t\tprint(math.floor(m / 2))\n\telse:\n\t\tx = math.floor(n / 2)\n\t\ty = 0\n\t\tif x != n / 2:\n\t\t\ty = math.floor(m / 2)\n\t\tout = m * x + y\n\t\tprint(out)\nmain()\n","in_str = input().split(' ')\nM = int(in_str[0])\nN = int(in_str[1])\nif M % 2 == 0:\n\tprint(N * int(M / 2))\nelif N % 2 == 0:\n\tprint(M * int(N / 2))\nelse:\n\tprint(N * int((M - 1) / 2) + int(N / 2))\n","(m, n) = input().split()\nsquare = int(m) * int(n)\nprint(square // 2)\n","from sys import stdin\nargs = stdin.readline().split(' ')\nm = int(args[0])\nn = int(args[1])\nprint(int(m * n / 2))\n","firstLine = [int(x) for x in input().split()]\nif firstLine[0] * firstLine[1] % 2 == 0:\n\tprint(int(firstLine[0] * firstLine[1] / 2))\nelse:\n\tprint(int((firstLine[0] * firstLine[1] - 1) / 2))\n","(m, n) = input().split()\nS = int(m) * int(n)\nprint(int(S / 2))\n","line = input()\n(m, n) = [int(i) for i in line.split()]\ncalc = m * n\nif calc & 1:\n\tcalc -= 1\nprint(calc // 2)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nz = a * b\nif z % 2 == 0:\n\tprint(int(z / 2))\nelse:\n\tprint(int(z / 2))\n","n = list(map(int, input().split()))\n\ndef jabong(m, n):\n\tif m % 2 == 0:\n\t\treturn m * n // 2\n\telif n % 2 == 0:\n\t\treturn m * n // 2\n\telse:\n\t\treturn (m - 1) // 2 + m * (n - 1) // 2\nprint(jabong(n[0], n[1]))\n","o = input().split()\nm = int(o[0])\nn = int(o[1])\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\nk2 = 0\nk1 = m // 2\nz = k1 * n\nif m % 2 != 0:\n\tk2 = n // 2\nprint(z + k2)\n","def solve(m, n):\n\ttileArea = 2 * 1\n\tboardArea = m * n\n\treturn boardArea / tileArea\n(m, n) = [int(y) for y in input().split()]\nans = solve(m, n)\nprint(int(ans))\n","M = str(input())\nx = M.split(' ')\nprint(int(x[0]) * int(x[1]) // 2)\n","number = str(input())\nm = int(number.split(' ')[0])\nn = int(number.split(' ')[1])\ndomino_tiles = m * n // 2\nprint(domino_tiles)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 0 and n % 2 == 0:\n\tnum = m * n / 2\nelif m % 2 == 0 and n % 2 != 0:\n\tnum = 0.5 * m * n\nelif m % 2 != 0 and n % 2 == 0:\n\tnum = 0.5 * m * n\nelse:\n\tnum = 0.5 * (m * n - 1)\nnum = int(num)\nprint(num)\n","s = input().split()\nn = int(s[0])\nk = int(s[-1])\nprint(n * k // 2)\n","i = input()\nl = i.split(' ')\nf = []\nfor i in l:\n\tf.append(int(i))\nh = f[0] * f[1] / 2\nprint(int(h))\n","(x, y) = map(int, input().split())\n(q, r) = divmod(x, 2)\nprint(y * q + r * (y // 2))\n","inp = [int(x) for x in input().split(' ')]\np = inp[0] * inp[1]\nprint(p // 2)\n","import math\n(M, N) = map(int, input().split())\nc = int(M * N / 2)\nprint(c)\n","(m, n) = sorted(map(int, input().split()), reverse=True)\nprint(m // 2 * n + m % 2 * n // 2)\n","from math import *\n(m, n) = input().split()\nM = int(m)\nN = int(n)\ncount = 0\nd1 = N * floor(M / 2)\ncount += d1\nif M % 2 != 0:\n\tcount += floor(N / 2)\nprint(count)\n","from math import ceil\nfrom math import floor\n\ndef foo(M, N):\n\treturn floor(M * N * 0.5)\n(a, b) = [int(x) for x in input().split()]\nprint(foo(a, b))\n","inputt = input()\n(n, m) = inputt.split(' ')\nprint(int(int(n) * int(m) / 2))\n","def solve(n, m):\n\tif n % 2 == 0 or m % 2 == 0:\n\t\treturn m * n // 2\n\telse:\n\t\treturn (m * n - 1) // 2\nt = 1\nwhile t > 0:\n\t(n, m) = [int(x) for x in input().split()]\n\tprint(solve(n, m))\n\tt -= 1\n","(m, n) = list(map(int, input().split()))\nj = m * n\nif j % 2 == 0:\n\tr = j // 2\n\tprint(r)\nelse:\n\ts = (j - 1) // 2\n\tprint(s)\n","(M, N) = map(int, input().split())\nS = M * N\nprint(S // 2)\n","import sys\nlines = sys.stdin.readlines()\ndata = lines[0].split(' ')\narea = int(data[0]) * int(data[1])\nanswer = area // 2\nprint(answer)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nif M * N % 2 == 0 and M + N >= 2:\n\tres = M * N / 2\nelif M * N % 2 != 0 and M + N >= 2:\n\tres = (M * N - 1) / 2\nelse:\n\tres = 0\nprint(int(res))\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nprint(int(M * N * 0.5))\n","import math\n\ndef domino_piling(m, n):\n\treturn math.floor(m * n / 2)\nip = input().split(' ')\nm = int(ip[0])\nn = int(ip[1])\nprint(domino_piling(m, n))\n","import math\nl = input().split(' ')\nm = int(l[0])\nn = int(l[1])\nprint(math.floor(m * n * 0.5))\n","import re\ndate = input()\nandron = re.findall('[0-9]+', date)\nlength = int(andron[0])\nwidth = int(andron[1])\nprint(length * width // 2)\n","import math\n(x, y) = input('').split()\nprint(math.trunc(int(x) * int(y) / 2))\n","(m, n) = map(int, input().split())\nsquares = m * n\ndomSize = 2\nans = 0\nmo = squares % domSize\nif mo != 0:\n\tans = int((squares - 1) / 2)\nelse:\n\tans = int(squares / 2)\nprint(ans)\n","(m, n) = map(int, input().split(' '))\nnum = m * n\nif num % 2 == 0:\n\tprint(num // 2)\nelse:\n\tout = (num - 1) // 2\n\tprint(out)\n","m = input()\na = m.split()\nb = []\nfor i in a:\n\tb.append(int(i))\narea = b[0] * b[1]\nprint(int(area / 2))\n","(n, m) = map(int, input().split())\ns = n * m\nif s % 2 == 0:\n\ts1 = s // 2\n\tprint(s1)\nelse:\n\ts1 = s // 2\n\tprint(s1)\n","(n, m) = map(int, input().split())\narea = n * m\ncount = 0\nfor i in range(area):\n\tif area <= 2 * i:\n\t\tcount = count + 1\nprint(count)\n","string = input().split()\nM = int(string[0])\nN = int(string[1])\nif M % 2 == 0 or N % 2 == 0:\n\tc = M * N / 2\nelse:\n\tc = M * N // 2\nprint(int(c))\n","s = input().split()\na = int(s[0])\nb = int(s[1])\nres = 0\nif a > 1 or b > 1:\n\tpoa = a / 2\n\tres += int(poa) * b\n\tif poa != int(poa):\n\t\tpob = b // 2\n\t\tres += pob\n\tprint(res)\nelse:\n\tprint(0)\n","tDim = input()\n(coloane, linii) = tDim.split(' ')\ncoloane_int = int(coloane)\nlinii_int = int(linii)\nif coloane_int % 2 == 0:\n\trezpartial = coloane_int * (linii_int / 2)\nelse:\n\trezpartial = (coloane_int - 1) * (linii_int / 2)\n\trezpartial = rezpartial + linii_int / 2\nrezpartial_int = int(rezpartial)\nprint(rezpartial_int)\n","(a, b) = input().split()\nm = int(a)\nn = int(b)\nif m % 2 == 0:\n\tdomino = m // 2 * n\n\tprint(domino)\nelif n % 2 == 0:\n\tdomino = n // 2 * m\n\tprint(domino)\nelse:\n\tdomino = m // 2 * n + n // 2\n\tprint(domino)\n","s = [int(x) for x in input().split()]\nprint(int(s[0] * s[1] / 2))\n","cad = input().split(' ')\nn1 = int(cad[0])\nn2 = int(cad[1])\nres = n1 * n2\nprint(res // 2)\n","def int_input_spliter_and_reciever():\n\tliste = []\n\tfor i in input().strip().split():\n\t\tliste.append(int(i))\n\treturn liste\n(n, m) = int_input_spliter_and_reciever()\nboard = n * m\nif board % 2:\n\tprint((board - 1) // 2)\nelse:\n\tprint(board // 2)\n","n = input()\nn = n.split(' ')\nk = int(n[0]) * int(n[1])\nprint(str(k // 2))\n","args = input().split(' ')\nm = int(args[0])\nn = int(args[1])\nprint(n * m // 2)\n","(x, y) = list(map(int, input().split()))\nif x % 2 == 0:\n\tprint(int(x / 2 * y))\nelif y % 2 == 0:\n\tprint(int(y / 2 * x))\nelse:\n\tprint(int(x // 2 * y + y // 2))\n","(m, n) = map(int, input().split())\nif 1 <= m <= n <= 16:\n\tans = m * n // 2\nprint(ans)\n","(a, b) = [int(i) for i in input().split()]\nimport math\nr = math.floor(a * b / 2)\nprint(r)\n","import math\nscanner = lambda : map(int, input().split())\n(m, n) = scanner()\nprint(math.floor(m * n / 2))\n","(m, n) = map(int, input().split())\nans = m // 2 * n\nif m % 2 == 0:\n\tpass\nelif n % 2 == 0:\n\tans += n // 2\nelse:\n\tans += (n - 1) // 2\nprint(ans)\n","input_data = input()\nlist_we_use = input_data.split(' ')\nx = []\nfor i in list_we_use:\n\tx.append(int(i))\ny = x[0] * x[1] / 2\nprint(int(y))\n","(b, l) = [int(i) for i in input().split()]\nn = b * l // 2\nprint(n)\n","__author__ = 'skinman95'\nfrom sys import stdin\n\ndef main():\n\tline = stdin.readline().strip()\n\twhile len(line) != 0:\n\t\t(m, n) = [int(c) for c in line.split()]\n\t\tprint(m * n // 2)\n\t\tline = stdin.readline().strip()\nmain()\n","import math\n(m, n) = input().split()\narea = int(m) * int(n)\nres = math.floor(area / 2)\nprint(res)\n","(m, n) = map(int, input().split())\nans = m // 2 * n\nr = m % 2\nif r:\n\tans += n // 2\nprint(ans)\n","strochka = input()\nstrochkanew = strochka.split()\nn1 = int(strochkanew[0])\nn2 = int(strochkanew[1])\ns = n1 * n2\nl = s // 2\nprint(l)\n","(m, n) = [int(x) for x in input().split()]\nluas = m * n\ndomino = luas // 2\nprint(domino)\n","input_data = input()\nlist_we_use = input_data.split(' ')\no = []\nfor i in list_we_use:\n\to.append(int(i))\na = o[0] * o[1]\nprint(a // 2)\n","d = str(input())\ns = d.split()\nm = int(s[0])\nn = int(s[1])\npa = m * n\nans = 0\nif pa % 2 == 1:\n\tpa -= 1\n\tans = int(pa / 2)\nelse:\n\tans = int(pa / 2)\nprint(ans)\n","D = input('')\nD = D.split()\nM = int(D[0])\nN = int(D[1])\nif M % 2 == 0:\n\tX = M // 2\n\tRes = X * N\nelse:\n\tXP = M // 2\n\tY = N\n\tX = N // 2\n\tRes = XP * Y + X\nprint(Res)\n","from math import *\nfrom collections import deque\nfrom copy import deepcopy\nimport sys\n\ndef inp():\n\treturn sys.stdin.readline().rstrip('\\r\\n')\n\ndef multi():\n\treturn map(int, input().split())\n\ndef lis():\n\treturn list(map(int, inp().split()))\n\ndef out(var):\n\tsys.stdout.write(str(var))\n\ndef printlist(a):\n\tfor p in range(0, len(a)):\n\t\tout(str(a[p]) + ' ')\n\ndef isPrime(n):\n\tif n <= 1:\n\t\treturn False\n\tif n <= 3:\n\t\treturn True\n\tif n % 2 == 0 or n % 3 == 0:\n\t\treturn False\n\ti = 5\n\twhile i * i <= n:\n\t\tif n % i == 0 or n % (i + 2) == 0:\n\t\t\treturn False\n\t\ti = i + 6\n\treturn True\n(n, m) = multi()\nout(n * m // 2)\n","m = input()\nfor i in range(len(m)):\n\tif m[i] == ' ':\n\t\ta = i\n\t\tbreak\nprint(int(m[:a]) * int(m[a + 1:]) // 2)\n","(n, k) = input().split()\nn = int(n)\nk = int(k)\nsquares = n * k\nif squares % 2 == 0:\n\tno = squares / 2\nelse:\n\tno = (squares - 1) / 2\nprint(int(no))\n","(m, n) = map(int, input().split())\narr = [[0 for j in range(n)] for i in range(m)]\ncount = 0\nfor i in range(m):\n\tfor j in range(n - 1):\n\t\tif not arr[i][j] and (not arr[i][j + 1]):\n\t\t\tarr[i][j] = arr[i][j + 1] = 1\n\t\t\tcount += 1\nfor j in range(n):\n\tfor i in range(m - 1):\n\t\tif not arr[i][j] and (not arr[i + 1][j]):\n\t\t\tarr[i][j] = arr[i + 1][j] = 1\n\t\t\tcount += 1\nprint(count)\n","numbers = str(input())\nlistt = numbers.split()\nm = listt[0]\nn = listt[1]\nboard = int(m) * int(n)\noutput = board // 2\nprint(output)\n","(m, n) = map(int, input().split())\na = m * n\ndsquares = 2 * 1\nprint(a // dsquares)\n","(M, N) = map(int, input().split())\ns = M * N\ndom = 0\nif s % 2 == 0:\n\tdom = s / 2\nelse:\n\tdom = (s - 1) / 2\nprint(int(dom))\n","(M, N) = [int(i) for i in input().split()]\ntotal = M // 2 * N + M % 2 * (N // 2)\nprint(total)\n","(l, b) = input().split(' ')\nif int(l) % 2 == 0:\n\tprint(int(int(b) * (int(l) / 2)))\nelif int(l) % 2 != 0 and int(b) % 2 == 0:\n\tprint(int((int(l) - 1) / 2 * int(b) + int(b) / 2))\nelif int(l) % 2 != 0 and int(b) % 2 != 0:\n\tprint(int((int(l) - 1) / 2 * int(b) + (int(b) - 1) / 2))\n","import math\nx = input()\ny = math.floor(int(x.split()[0]) * int(x.split()[1]) / 2)\nprint(str(y))\n","(n, m) = map(int, input().split(' '))\n\ndef solve(n, m):\n\tif n * m % 2 == 0:\n\t\tprint(m * n // 2)\n\telse:\n\t\tprint((m * n - 1) // 2)\nsolve(n, m)\n","nu = input().split()\nprint(int(nu[0]) * int(nu[1]) // 2)\n","(n, p) = map(int, input().split())\nprint(n * p // 2)\n","from math import *\n(m, n) = list(map(int, input().split()))\narea = 2\ncount = ceil(int(m * n / area))\nprint(count)\n","(x, y) = map(int, input().split())\nxy = x * y\nprint((xy - xy % 2) // 2)\n","a = input()\nnums = a.split()\nm = int(nums[0])\nn = int(nums[1])\nif m % 2 == 0 or n % 2 == 0:\n\tout = m * n / 2\nelse:\n\tout = (m * n - 1) / 2\nprint(int(out))\n","a = input()\na = list(map(int, a.split()))\nm = a[0]\nn = a[1]\nhc = int(m / 2)\nvc = n\ntc = hc * vc\nif m % 2 != 0:\n\tec = int(n / 2)\n\ttc = tc + ec\nprint(tc)\n","import math\na = list(map(int, input().split()))\nprint(int(a[0] * a[1] / 2))\n","def func(x):\n\treturn x // 2\n(m, n) = map(int, input().split())\nprint(func(m * n))\n","def main():\n\tdimensions = list(map(int, input().split()))\n\tproduct = dimensions[0] * dimensions[1]\n\treturn product // 2\nprint(main())\n","(n, m) = map(int, input().split())\nk = 2\nl = 1\nj = n * m\np = j / k\nprint(int(p))\n","def sol(a, b):\n\treturn a * b // 2\n(a, b) = map(int, input().split(' '))\nprint(sol(a, b))\n","SQUARES_PARA = input().split(' ')\nSQUARES_AREA = int(SQUARES_PARA[0]) * int(SQUARES_PARA[1])\nprint(int(SQUARES_AREA / 2))\n","s1 = input()\nl1 = list(s1.split(' '))\nm = int(l1[0])\nn = int(l1[1])\na = m * n\ncount = 0\nwhile 1:\n\tif a == 0 or a == 1:\n\t\tbreak\n\ta = a - 2\n\tcount = count + 1\nprint(count)\n","(a, b) = [int(i) for i in input().split()]\nx = a * b\nz = x // 2\nprint(z)\n","(a, b) = map(int, input('').split(' '))\nbigger = max(int(a / 2) * b, int(b / 2) * a)\nans = bigger\nif bigger == int(a / 2) * b:\n\tans = ans + a % 2 * int(b / 2)\nelse:\n\tans = ans + b % 2 * int(a / 2)\nprint(ans)\n","l = list(map(int, input().rstrip().split()))\nn = l[0]\nm = l[1]\nif n == 1 and m == 2 or (n == 2 and m == 1):\n\tprint(1)\n\texit()\nx = 0\ny = 0\nif n % 2 == 0:\n\tx = n // 2\n\ty = m\n\tprint(x * y)\n\texit()\nelse:\n\tx = n // 2\n\tif m % 2 == 0:\n\t\ty = m\n\t\tprint(x * y + m // 2)\n\t\texit()\n\telse:\n\t\ty = m\n\t\tprint(x * y + m // 2)\n","(a, b) = [int(i) for i in input().split()]\nreszta = a % 2\ncale = int(a / 2)\ncount = 0\ncount = b * cale + reszta * int(b / 2)\nprint(count)\n","(m, n) = list(map(int, input().split()))\nans = m * n\ngiven = 2\nprint(int(ans / given))\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nsquares = m // 2 * n\nif m % 2 == 1:\n\tsquares += n // 2\nprint(squares)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ncount = 0\nif n % 2 == 0:\n\tcount = m * (n // 2)\nelif n % 2 != 0:\n\tcount = round((n - 1) * (m / 2) + m // 2)\nprint(count)\n","(M, N) = map(int, input().split())\na = M * N\nb = a // 2\nprint(b)\n","ipt = input()\nipt = ipt.strip().split()\nm = int(ipt[0])\nn = int(ipt[1])\nprint(m * n // 2)\n","(m, n) = input().split()\nn = int(n)\nm = int(m)\nboard_size = m * n\ncounter = 0\nfor i in range(board_size):\n\tif board_size - 2 > 0:\n\t\tboard_size -= 2\n\t\tcounter += 1\n\tif board_size - 2 < 0:\n\t\tprint(counter)\n\t\tbreak\n\tif board_size - 2 == 0:\n\t\tcounter += 1\n\t\tprint(counter)\n\t\tbreak\n","(M, N) = map(int, input().split())\nif N % 2 == 0:\n\tresult = N * M / 2\n\tprint(int(result))\nelse:\n\tresult = N // 2 * M\n\tprint(int(result + M // 2))\n","(n, w) = input().split()\nprint(int(n) * int(w) // 2)\n","import math\ns = list(map(int, input().split()))\nm = s[0]\nn = s[1]\nans = math.floor(m * n / 2)\nprint(int(ans))\n","lst = list(map(int, input().split()))\nprint(lst[0] * lst[1] // 2)\n","import sys\ndata = sys.stdin.readlines()[0].split()\n(n, m) = (int(data[0]), int(data[1]))\nif n % 2 == 1 and m % 2 == 1:\n\tsys.stdout.write(str(int((n * m - 1) / 2)))\nelse:\n\tsys.stdout.write(str(int(n * m / 2)))\n","ls = [int(x) for x in input().split()]\nprint(ls[0] * ls[1] // 2)\n","(M, N) = list(map(int, input().split()))\nboard = M * N\ny = board // 2\nprint(y)\n","(m, n) = map(int, input().split())\nsol = -1\nif m * n % 2:\n\tsol = m * (n // 2) + m // 2\nelif not (m % 2 or n % 2):\n\tsol = m // 2 * n\nelse:\n\tif n % 2:\n\t\t(m, n) = (n, m)\n\tsol = m * n // 2\nprint(sol)\n","import math\nnm = input().split(' ')\n(n, m) = (int(nm[0]), int(nm[1]))\nk = math.floor(n * m / 2)\nprint(k)\n","v = input()\nsplited = v.split()\nm = int(splited[0])\nn = int(splited[1])\np = 0\nif m % 2 == 0:\n\tp = m / 2 * n\nelse:\n\tp = (m - 1) / 2 * n + int(n / 2)\nprint(int(p))\n","(m, n) = map(int, input().split())\ntemp = m * n\nd = temp // 2\nprint(d)\n","string = input()\ns = string.split(' ')\nn = int(s[0])\nm = int(s[1])\ns = m * n\ncount = s // 2\nprint(count)\n","(a, b) = [int(x) for x in input().split()]\nif a % 2 == 0 or b % 2 == 0:\n\tprint(int(a * b / 2))\nelse:\n\tx = max((a - 1) * b / 2 + (b - 1) / 2, (b - 1) * a / 2 + (a - 1) / 2)\n\tprint(int(x))\n","a = input()\nlength = a.split()\nM = int(length[0])\nN = int(length[1])\ntotal = 0\nwhile True:\n\tif M > N and N >= 1:\n\t\ttotal += N\n\t\tM = M - 2\n\telif M < N and M >= 1:\n\t\ttotal += M\n\t\tN = N - 2\n\telif M == N and N > 1:\n\t\ttotal += M\n\t\tN = N - 2\n\telse:\n\t\tbreak\nprint(total)\n","(n, m) = [int(i) for i in input().split()]\nq = n * m\nq = q / 2\nq = int(q)\nprint(q)\n","(a, b) = map(int, input().split())\neq = a * b // 2\nprint(eq)\n","size = list(map(int, input().split()))\narea = size[0] * size[1]\ndom = area // 2\nprint(dom)\n","Str = input()\nNc = Str.split(' ')\nN = int(Nc[0])\nM = int(Nc[1])\nAns = int(0)\nAns += int(N / 2) * int(M / 2) * 2\nExt = N % 2 * (M - 1) + M % 2 * (N - 1) + 1\nif Ext != 1:\n\tAns += int(Ext / 2)\nprint(int(Ans))\n","x = input()\nl1 = x.split()\ny = []\nl1 = [int(j) for j in l1]\ny.append(l1)\nq = y[0][0] * y[0][1]\nw = q // 2\nprint(w)\n","st = input().split(' ')\nM = int(st[0])\nN = int(st[1])\nS = M * N\nprint(S // 2)\n","(m, n) = input().split(' ')\nkol = int(m) * int(n) // 2\nprint(kol)\n","(m, n) = map(int, input().split())\nif m == 1 and n > 1:\n\tprint(int(n / 2))\nelif m > 1 and n == 1:\n\tprint(int(m / 2))\nelse:\n\tr = int(m / 2)\n\tresult = r * n\n\tif m % 2 != 0:\n\t\tresult += int(n / 2)\n\tprint(result)\n","(m, n) = map(int, input().split())\nx = m // 2 * n\nif m % 2 == 1:\n\tx += n // 2\nprint(x)\n","a = list(map(int, input().split(' ')))\nfrom math import *\nno = floor(float(a[0] * a[1] / 2))\nprint(no)\n","input = list(map(int, input().split()))\nm = input[0]\nn = input[1]\ntotal_dominoes = 0\nportrait_dominoes = int(n / 2)\ntotal_dominoes += portrait_dominoes * m\nvertical_space_left = n - portrait_dominoes * 2\nif vertical_space_left > 0:\n\tlandscape_dominoes = int(m / 2)\n\ttotal_dominoes += landscape_dominoes\nprint(total_dominoes)\n","board = input().split()\ndominoes = int(board[0]) * int(board[1]) / 2\nprint(int(dominoes))\n","(M, N) = map(int, input().split())\nsum = M * N // 2\nprint(sum)\n","line = input()\nlist = line.split()\nn = int(list[0])\nm = int(list[1])\na = m * n // 2\nprint(a)\n","(m, n) = list(map(int, input().strip().split()))\nz = int((m * n - 1) / 2)\nw = int(m * n / 2)\nif m * n % 2 == 0:\n\tprint(w)\nif m * n % 2 != 0:\n\tprint(z)\n","def solution():\n\t(m, n) = (int(i) for i in input().split())\n\tprint(m * n // 2)\nsolution()\n","s = input('')\nm = s.split()\nx = int(m[0])\ny = int(m[1])\nif 1 <= x <= y <= 16:\n\tprint(int(x * y / 2))\n","(M, N) = map(int, input().split())\n1 <= M <= N <= 16\nmax = M * N // 2\nprint(max)\n","N = [int(x) for x in input().split()]\nl = N[0] * N[1] / 2\nprint(int(l))\n","(m, n) = [int(x) for x in input().split()]\nans = 0\nans += m // 2 * n\nif m & 1:\n\tans += n // 2\nprint(ans)\n","(x, y) = map(int, input().split())\ncount = 0\nsum = int(x * y / 2)\nprint(sum)\n","(m, n) = map(int, input().split())\nc = m // 2 * n\nif m % 2 == 1:\n\tc += n // 2\nprint(c)\n","entrada = input()\nentrada = [int(x) for x in entrada.split()]\nM = entrada[0]\nN = entrada[1]\nprint(int(M * N / 2))\n","(m, n) = map(int, input().split())\ndomino = 2\ncount = m * n // domino\nprint(count)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nif M % 2 == 0 or N % 2 == 0:\n\tresult = M * N // 2\nelse:\n\tresult = (M * N - 1) // 2\nprint(result)\n","try:\n\t(row, column) = map(int, input().split())\n\tif row % 2 == 0 or column % 2 == 0:\n\t\tprint(row * column // 2)\n\telse:\n\t\tprint((row - 1) // 2 * column + (column - 1) // 2)\nexcept EOFError:\n\tpass\n","n = list(map(int, input().split(' ')))\nK = n[0] * n[1]\nprint(int(K / 2))\n","[M, N] = [int(i) for i in input().split()]\nif M % 2 == 0 and N % 2 == 0:\n\tprint(int(N * M / 2))\nelif M % 2 == 1 and N % 2 == 0:\n\tif M != 1:\n\t\tprint(int(N * M / 2))\n\telse:\n\t\tprint(int(N / 2))\nelif M % 2 == 0 and N % 2 == 1:\n\tif N != 1:\n\t\tprint(int(N * M / 2))\n\telse:\n\t\tprint(M / 2)\nelif M % 2 == 1 and N % 2 == 1:\n\tprint(int((N - 1) * (M - 1) / 2 + (M - 1) / 2 + (N - 1) / 2))\n","n = input()\nif n[1] == ' ':\n\tprint(int(n[0]) * int(n[2:]) // 2)\nelse:\n\tprint(int(n[0:2]) * int(n[3:]) // 2)\n","import math\n(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nsq = m * n\nif sq % 2 == 0:\n\tprint(math.trunc(sq / 2))\nelse:\n\tprint(math.trunc((sq - 1) / 2))\n","from sys import stdin\na = stdin.readline().rstrip().split()\na = [int(i) for i in a]\nprint(a[0] * a[1] // 2)\n","(m, n) = list(map(int, input().split()))\nt = m * n\nprint(t // 2)\n","(n, k) = map(int, input().split())\ndomino = n * k // 2\nprint(domino)\n","import sys\n\ndef solve():\n\t(m, n) = map(int, input().split())\n\tans = m * n // 2\n\tprint(ans)\nsolve()\n","x = input('').split()\nm = int(x[0])\nn = int(x[1])\nnumber = m / 2 * n\nprint(int(number))\n","input_list = [int(n) for n in input().split()]\nN = input_list[0]\nM = input_list[1]\nprint(int(M * N / 2))\n","n = input().split()\nM = int(n[0])\nN = int(n[1])\na = max(M, N)\nb = min(M, N)\nif a % 2 == 0:\n\tnum_length = a / 2\n\tnum_width = b\n\tnum_all = num_length * num_width\nelse:\n\tnum_length = int(a / 2)\n\tnum_width = b\n\tnum_all = num_length * num_width + int(b / 2)\nprint(int(num_all))\n","size = [int(n) for n in input().split(' ')]\nrows = size[0]\ncols = size[1]\nif cols % 2 == 0:\n\tacross = cols // 2\n\tdown = rows\n\tprint(across * down)\nelse:\n\tacross = cols // 2\n\tdown = rows\n\tlast_col = rows // 2\n\tprint(across * down + last_col)\n","dims = list(map(int, input().split()))\nprint(dims[0] * dims[1] // 2)\n","in_string = input()\nin_string = in_string.split(' ')\nh = int(in_string[0])\nv = int(in_string[1])\nsum = 0\nif h % 2 == 0:\n\tsum = h / 2 * v\nelif h > 1:\n\tsum = (h - 1) / 2 * v\n\tif v % 2 == 0:\n\t\tsum = sum + v / 2\n\telif v > 1:\n\t\tsum = sum + (v - 1) / 2\n\telse:\n\t\tpass\nelif v > 1:\n\tif v % 2 == 0:\n\t\tsum = v / 2\n\telse:\n\t\tsum = (v - 1) / 2\nprint(int(sum))\n","(M, N) = list(map(int, input().strip().split()))\n\ndef isEven(num):\n\treturn not bool(num % 2)\nif isEven(M) or isEven(N):\n\tprint(int(M * N / 2))\nelse:\n\tprint(int(M * N / 2))\n","def solve(m, n):\n\ttileArea = 2 * 1\n\tboardArea = m * n\n\treturn boardArea / tileArea\n(m, n) = list(map(int, input().split(' ')))\nprint(int(solve(m, n)))\n","square = input()\nsqua = square.split(' ')\nm = int(squa[0])\nn = int(squa[1])\nrs = int(m * n / 2)\nprint(rs)\n","(m, n) = input().split(' ')\nif int(m) > 0 and int(n) > 0:\n\tprint(int(m) * int(n) // 2)\n","inp = input()\ninfo = inp.split()\nresult = int(info[0]) * int(info[1]) / 2\nprint(int(result))\n","(a, b) = map(int, input().split())\ny = int(a * b)\ny = int(y / 2)\nprint(y)\n","(m, n) = map(int, input().split())\ncounter_m = int(m / 2)\nif m % 2 == 0:\n\tcounter = counter_m * n\nelse:\n\tcounter = counter_m * n + int(n / 2)\nprint(counter)\n","import io\nimport os\nimport math\n(m, n) = [int(i) for i in input().split()]\nprint(math.floor(m * n / 2))\n","t = [int(s) for s in input().split()]\nprint(t[0] * t[1] // 2)\n","from math import *\na = input().split()\nprint(floor(int(a[0]) * int(a[1]) * 0.5))\n","import sys\n(a, b) = map(int, sys.stdin.readline().split())\na = a * b\nm = int((a - a % 2) / 2)\nprint(m)\n","(m, n) = [int(n) for n in input().split()]\ncount = m // 2 * n\nif m % 2 == 1:\n\tcount += n // 2\nprint(count)\n","t = input().split()\nfor i in range(len(t)):\n\tt[i] = int(t[i])\nm = t[0]\nn = t[1]\nif m > n:\n\tsmaller = n\n\tbig = m\nelse:\n\tsmaller = m\n\tbig = n\nf = smaller // 2\ng = f * big\nif smaller % 2 == 1:\n\th = big // 2\n\tx = g + h\nelse:\n\tx = g\nprint(x)\n","(m, n) = map(int, input().split())\ntotsq = m * n\nres = totsq // 2\nprint(res)\n","(s, k) = input().split(' ')\nprint(int(s) * int(k) // 2)\n","parameters = [int(x) for x in input().split()]\nanswer = int(parameters[0] * parameters[1] / 2)\nprint(answer)\n","(x, y) = input().split()\n(x, y) = (int(x), int(y))\na = int(x // 2 * y)\nif x % 2 == 1:\n\ta += y // 2\nprint(a)\n","MN = list(map(int, input().split()))\nM = MN[0]\nN = MN[1]\nprint(M * N // 2)\n","(m, n) = [int(x) for x in input().strip().split()]\ncount = m // 2 * n\nrem = m % 2 * n\ncount += rem // 2\nprint(count)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nsqr = m * n\nx = int(sqr / 2)\nprint(x)\n","a = input()\nb = a.split()\ns = int(b[0])\nm = int(b[1])\nd = s * m // 2\nprint(d)\n","numbers = input().split()\nn = int(numbers[0])\nm = int(numbers[1])\nres = n * m // 2\nprint(res)\n","P = input().split(' ')\nL = [int(x) for x in P]\ncount = 0\ntotal = L[0] * L[1]\nfor x in range(2, total + 1, 2):\n\tif x <= total:\n\t\tcount = count + 1\nprint(count)\n","(M, N) = [int(i) for i in input().split()]\narea = M * N\ndominoes = area // 2\nif 0 < M < 17 and 0 < N < 17:\n\tprint(dominoes)\n","(m, n) = [int(x) for x in input('').split()]\nans = m * n // 2\nprint(ans)\n","def ii():\n\treturn int(input())\n\ndef fi():\n\treturn float(input())\n\ndef si():\n\treturn input()\n\ndef mi():\n\treturn map(int, input().split())\n\ndef li():\n\treturn list(mi())\nimport math\n(n, m) = mi()\nprint(n * m // 2)\n","def seperateints(x):\n\tk = ''\n\tl = []\n\tfor i in x:\n\t\tif i == ' ':\n\t\t\tl.append(int(k))\n\t\t\tk = ''\n\t\t\tcontinue\n\t\tk = k + i\n\tl.append(int(k))\n\treturn l\nx = input()\nl = seperateints(x)\nprint(l[0] * l[1] // 2)\n","(m, n) = map(int, input().split())\nboard_area = m * n\ndomino_area = 2\nn_domino = board_area / domino_area\nprint(int(n_domino))\n","def maxi(m, n):\n\treturn m * n // 2\n(m, n) = map(int, input().split())\nprint(maxi(m, n))\n","import math\n[M, N] = [int(i) for i in input().split()]\na = int(M * N / 2)\nprint(a)\n","ar = list(map(int, input().rstrip().split()))\nm = ar[0] * ar[1]\nprint(int(m / 2))\n","import sys\nimport math\n[m, n] = sys.stdin.readline().strip().split(' ')\nprint(int(math.floor(int(m) * int(n) / 2)))\n","(n, m) = input().split()\nprint(int(int(n) * int(m) * 0.5))\n","(l, p) = [int(a) for a in input().split(' ')]\nprint(l * p // 2)\n","inp = input().split()\n(m, n) = (max(int(inp[0]), int(inp[1])), min(int(inp[0]), int(inp[1])))\nif m == n:\n\tprint(m * n // 2)\nelse:\n\tprint(m * n // 2)\n","def create_board(w, h):\n\tf = []\n\tfor y in range(h):\n\t\tfor x in range(w):\n\t\t\tf.append([x, y])\n\treturn f\n\ndef domino_piling(b):\n\tfields = b[:]\n\ts = 0\n\tfor field in fields:\n\t\tif [field[0] + 1, field[1]] in fields:\n\t\t\ts += 1\n\t\t\tfields.remove([field[0] + 1, field[1]])\n\t\telif [field[0], field[1] + 1] in fields:\n\t\t\ts += 1\n\t\t\tfields.remove([field[0], field[1] + 1])\n\treturn s\nmn = list(map(int, input().split()))\n(width, height) = (mn[0], mn[1])\nboard = create_board(width, height)\nprint(domino_piling(board))\n","def solve(a, b):\n\tm = min(a, b)\n\tn = max(a, b)\n\tres = int(n / 2)\n\tres *= m\n\tres += int(n % 2 * m / 2)\n\treturn res\n(m, n) = map(int, input().split())\nprint(solve(m, n))\n","n = input().split()\nx = int(n[0])\ny = int(n[1])\nc = x * y\nprint(c // 2)\n","(rows, cols) = tuple(map(int, input().split()))\nif cols % 2 == 0:\n\tresult = cols * rows / 2\nelse:\n\tresult = cols // 2 * rows + rows // 2\nprint(int(result))\n","def cantDominoes(x, y):\n\tprint(int(x * y / 2))\ns = input()\ns = s.split()\ncantDominoes(int(s[0]), int(s[1]))\n","x = input()\n(m, n) = x.split()\nboard = int(m) * int(n)\nprint(board // 2)\n","s = input()\nproduct = 1\ns = s.split()\ns = [int(x) for x in s]\nfor x in s:\n\tproduct = product * int(x)\nr = product // 2\nprint(r)\n","import sys\n\ndef main():\n\t(M, N) = [int(x) for x in sys.stdin.readline().strip().split()]\n\tprint(M * N // 2)\nmain()\n","arr = [int(x, 10) for x in input().split()]\na = arr[0] * arr[1] // 2\nprint(a)\n","import math\n(m, n) = map(int, input().split())\nz = m * n\nk = math.floor(z / 2)\nprint(k)\n","def domino(m, n):\n\tif m == 1 and n == 1:\n\t\treturn 0\n\telif m == 1:\n\t\treturn n // 2\n\telif n == 1:\n\t\treturn m // 2\n\telif m % 2 == 0 and n % 2 == 0:\n\t\treturn m * n / 2\n\telif m % 2 == 0 and n % 2 == 1:\n\t\treturn domino(m, n - 1) + domino(m, 1)\n\telif m % 2 == 1 and n % 2 == 0:\n\t\treturn domino(m - 1, n) + domino(1, n)\n\telse:\n\t\treturn domino(m - 1, n - 1) + domino(m, 1) + domino(1, n)\nargs = input().split()\nm = int(args[0])\nn = int(args[1])\nprint(int(domino(m, n)))\n","import math\n(m, n) = input().split()\nans = math.floor(int(m) * int(n) / 2)\nprint(ans)\n","(z, y) = [int(z) for z in input().split()]\nif z * y % 2 == 0:\n\tprint(int(z * y / 2))\nelse:\n\tprint(z * y // 2)\n","t = input().split(' ')\nm = int(t[0])\nn = int(t[1])\nprint(m * n // 2)\n","from sys import stdin, stdout\n(n, m) = [int(x) for x in stdin.readline().rstrip().split()]\nstdout.write(str(n * m // 2))\n","x = input().split(' ')\nproduct = 1\nfor i in x:\n\tproduct *= int(i)\nprint(product // 2)\n","a = input().split()\nlength = int(a[0])\nwidth = int(a[1])\nresult = 0\nif length * width % 2 == 0:\n\tresult = int(length * width / 2)\nelse:\n\tresult = int((length * width - 1) / 2)\nprint(result)\n","s = input().split()\nx = int(s[0])\ny = int(s[1])\nif x % 2 == 1 and y % 2 == 1:\n\tprint(int((x * y - 1) / 2))\nelse:\n\tprint(int(x * y / 2))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(m * n / 2 - 0.5))\n","def main():\n\tsize = input().split()\n\tboard = int(size[0]) * int(size[1])\n\tprint(board // 2)\nmain()\n","(a, b) = map(int, input().split())\nprint(int(a * b * 0.5))\n","(a, b) = input().split()\nlength = int(a)\nwidth = int(b)\nif length % 2 != 0 and width % 2 != 0:\n\tprint(int((length * width - 1) / 2))\nelse:\n\tprint(int(length * width / 2))\n","dominosize = 2 * 1\ni = input().split()\nboardsize = int(i[0]) * int(i[1])\nprint(boardsize // dominosize)\n","import math\nn = input()\nline = n.split()\ns = math.floor(int(line[0]) * int(line[1]) * 0.5)\nprint(s)\n","def domino_piling():\n\t(m, n) = input().split()\n\ts = int(m) * int(n)\n\td = 2\n\tprint(int(s / d))\ndomino_piling()\n","a = input()\n(M, N) = [int(i) for i in a.split()]\nif M % 2 == 0 and N % 2 == 0:\n\tnum = int(M * N / 2)\nif M % 2 != 0 or N % 2 != 0:\n\tnum = int(M * N / 2)\nprint(num)\n","import math\nimport os\nimport random\nimport re\nimport sys\nmn = input().rstrip().split()\nm = int(mn[0])\nn = int(mn[1])\nmax = int(m * n / 2)\nprint(max)\n","(n, m) = [int(i) for i in input().split()]\nS = n * m\nprint(S // 2)\n","import math\n(n, k) = list(map(int, input().split()))\nprint(math.floor(n * k / 2))\n","(m, n) = map(int, input().split())\nif m < 2 and n < 2:\n\tprint(0)\nelse:\n\tprint(min(n, m) + (max(n, m) - 2) * min(n, m) // 2)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nle = max(M, N)\npe = min(M, N)\nif le % 2 == 0:\n\tprint(int(le / 2 * pe))\nelse:\n\tprint(int(le // 2 * pe + pe // 2))\n","(hight, wight) = tuple(map(int, input().split()))\nif hight % 2 == 0:\n\tres = hight * wight // 2\nelif wight % 2 == 0:\n\tres = hight * wight // 2\nelse:\n\tres = hight * (wight + 1) // 2 - hight // 2 - 1\nprint(res)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nabc = int(m * n / 2)\nprint(abc)\n","bs = [int(i) for i in input().split()]\nsquares = bs[0] * bs[1]\nif squares % 2 == 0:\n\tprint(int(squares / 2))\nelse:\n\tprint(int((squares - 1) / 2))\n","(m, n) = tuple(map(int, input().split(' ')))\n\ndef dominoshki(m, n):\n\tmatr = [[0 for j in range(n)] for i in range(m)]\n\tfor i in range(1, n + 1):\n\t\tmatr[0][i - 1] = i // 2\n\tfor j in range(1, n):\n\t\tif (j + 1) % 2 == 0:\n\t\t\tfor i in range(1, m):\n\t\t\t\tmatr[i][j] = matr[i - 1][j] + (j + 1) / 2\n\t\telse:\n\t\t\tc = [matr[0][j] + 1, matr[0][j]] * m\n\t\t\tfor i in range(1, m):\n\t\t\t\tmatr[i][j] = matr[i - 1][j] + c[i - 1]\n\treturn int(matr[m - 1][n - 1])\nprint(dominoshki(m, n))\n","print(eval(input().replace(' ', '*')) // 2)\n","(m, n) = list((int(x) for x in input().split()))\nprint(m * n // 2)\n","a1 = []\na2 = []\nb = 0\nm = 0\nn = 0\nd = float(2)\na1 = input()\na2 = a1.split()\nm = float(a2[0])\nn = float(a2[1])\nP = m * n\nif P % d > 0:\n\tP = P - 1\nL = P / d\nprint(int(L))\n","def get_max_count_dominoes(board_size):\n\tsize_dominoe = 2\n\tcount_dominoes = board_size // size_dominoe\n\treturn count_dominoes\n(m, n) = map(int, input().split())\nboard_size = m * n\nprint(get_max_count_dominoes(board_size))\n","def iip():\n\treturn int(input())\n\ndef sip():\n\treturn input()\n\ndef mip():\n\treturn map(int, input().split())\n\ndef lip():\n\treturn list(map(int, input().split()))\n(m, n) = mip()\nprint(m * n // 2)\n","(n, k) = map(int, input(' ').split())\nmax_num = n * k / 2\nprint(int(max_num))\n","(m, n) = [int(n) for n in input().split()]\nsize = m * n\nif 1 <= m <= n <= 16:\n\tif size % 2 == 0:\n\t\tprint(int(size / 2))\n\telif size % 2 != 0:\n\t\tprint(int((size - 1) / 2))\n","n = list(input().split())\narea = int(n[0]) * int(n[1])\nanswer = int(area / 2)\nprint(answer)\n","import math\nA = input().split()\nn = int(A[0])\nm = int(A[1])\nans1 = int(0)\nans2 = int(0)\nans1 += int(n / 2) * m + n % 2 * m / 2\nans2 += int(m / 2) * n + m % 2 * n / 2\nprint(int(max(ans1, ans2)))\n","(a, b) = input().split()\na = int(a)\nb = int(b)\np = a * b // 2\nprint(p)\n","(x, y) = [int(i) for i in input().split()]\nif x % 2 != 0 and y % 2 != 0:\n\tprint(x // 2 * y + y // 2)\nelif x % 2 == 0:\n\tprint(x // 2 * y)\nelse:\n\tprint(y // 2 * x)\n","import math\n(M, N) = input().split()\nprint(math.floor(int(M) * int(N) / 2))\n","import sys\nimport math\n(m, n) = map(int, sys.stdin.readline().split())\narea = m * n\nans = math.floor(area / 2)\nprint(ans)\n","a = map(int, input().split())\nresult = 1\nfor x in a:\n\tresult *= x\nprint(int(result / 2))\n","board = str(input())\nboard_values = board.split(' ')\nm = int(board_values[0])\nn = int(board_values[1])\narea = m * n\nby_2 = area / 2\nprint(int(by_2))\n","def how_many(n, m):\n\treturn n * m // 2\n(n, m) = map(int, input().split())\nprint(how_many(n, m))\n","(x, y) = map(int, input().split())\ns = 0\nif y % 2 == 0:\n\tb = 0\n\ts = y / 2 * x\nelse:\n\tb = 1\n\ts = (y - 1) / 2 * x\nif x % 2 == 0:\n\tc = x / 2\nelse:\n\tc = (x - 1) / 2\ns = s + c * b\nprint('%d' % s)\n","import sys, math\ninput = sys.stdin.readline\n\ndef getInt():\n\treturn int(input())\n\ndef getVars():\n\treturn map(int, input().split())\n\ndef getArr():\n\treturn list(map(int, input().split()))\n\ndef getStr():\n\treturn input().strip()\n(n, m) = getVars()\nif m % 2 == 0:\n\tm1 = m\n\tm2 = n\nelse:\n\tm1 = n\n\tm2 = m\nres = m1 // 2 * m2\nif m1 % 2 == 1:\n\tres += m2 // 2\nprint(res)\n","N = input()\nline = N.split()\nimport math\nk = math.floor(int(line[0]) * int(line[1]) / 2)\nprint(k)\n","s = input().split()\nM = int(s[0])\nN = int(s[1])\nk = 0\nif N > M:\n\tk = N // 2\n\tL = k * M\n\tif M == 2:\n\t\tL = N\n\tif M > 2:\n\t\th = N * M\n\t\tL = h // 2\nelse:\n\th = N * M\n\tL = h // 2\nprint(L)\n","import math\n(m, n) = (int(x) for x in input().split())\narea = m * n\ndominoarea = 2\nx = math.floor(area / 2)\nprint(x)\n","string = input().split()\nwidth = int(string[0])\nheight = int(string[1])\nif width % 2 == 1 and height % 2 == 1:\n\tprint(int((width * height - 1) / 2))\nelse:\n\tprint(int(width * height / 2))\n","desk = input().split()\na = int(desk[0])\nb = int(desk[1])\ns = a * b\nprint(s // 2)\n","MN = sorted(list(map(lambda x: int(x), input().split(' '))), reverse=True)\nprint(int(MN[0] * MN[1] * 1 / 2))\n","i = input().split(sep=' ')\nm = int(i[0])\nn = int(i[1])\nres = int(m / 2) * n + m % 2 * int(n / 2)\nprint(int(res))\n","ipt = input().split()\n(a, b) = list(map(int, ipt))\nprint(a * b // 2)\n","(m, n) = list(map(eval, input().split()))\nprint(m * n // 2)\n","n = list(map(int, input().split()))\ns = n[0] * n[1]\nprint(s // 2)\n","ar = input().split()\nprint(int(int(ar[0]) * int(ar[1]) / 2))\n","(a, b) = map(int, input().split())\ns = a * b\np = s // 2\nprint(p)\n","(m, n) = map(int, input().split())\nprvi = n // 2 * m\nprvi += m // 2 * (n - 2 * (n // 2))\ndrugi = m // 2 * n\ndrugi += n // 2 * (m - 2 * (m // 2))\nprint(max(prvi, drugi))\n","w = input()\nlista = w.split()\nl1 = int(lista[0])\nl2 = int(lista[1])\na = l1 * l2\nx = a // 2\nprint(x)\n","def domino_piling():\n\t(m, n) = map(int, input().strip().split())\n\tif not m or not n:\n\t\treturn 0\n\treturn m * n // 2\nprint(domino_piling())\n","board = str(input())\nboard_values = board.split(' ')\nprint(int(int(board_values[0]) * int(board_values[1]) / 2))\n","def Domino(n, m):\n\tval = int(n * m / 2)\n\treturn val\n(n, m) = list(map(int, input().split(' ')))\nprint(Domino(n, m))\n","(M, N) = list(map(int, input().split(' ')))\nt = M * N\nans = t // 2\nprint(ans)\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nboard_size = m * n\nprint(int(board_size / 2))\n","a = input().split()\nm = int(a[0])\nn = int(a[1])\ns = m * n\np = s // 2\nprint(p)\n","(a, b) = map(int, input().split())\nf = 2\nprint(a * b // 2)\n","(M, N) = map(int, input().split())\nA = 2\nA2 = M * N\nprint(A2 // A)\n","def dominoPiling():\n\t(m, n) = map(int, input().strip().split())\n\tif not m or not n:\n\t\treturn 0\n\tp = m * n\n\tdominos = p // 2\n\treturn dominos\nprint(dominoPiling())\n","inp = input('')\nx = inp.split(' ')\nn = int(x[0])\nm = int(x[1])\nif m % 2 == 0:\n\tt = n\n\tn = m\n\tm = t\nif n % 2 == 1:\n\tprint(n // 2 * m + m // 2)\nelse:\n\tprint(n // 2 * m)\n","(a, b) = map(int, input().split())\nif a <= b:\n\tsm = a\n\tbg = b\nelse:\n\tsm = b\n\tbg = a\nif bg % 2 == 0:\n\tans = bg // 2 * sm\nelse:\n\tans = bg // 2 * sm + sm // 2\nprint(ans)\n","(n, m) = [int(p) for p in input().split()]\ns = n * m\nprint(s // 2)\n","s = input().split()\nm = int(s[0])\nn = int(s[1])\nt = m * n\nx = t / 2\ny = int(x)\nprint(y)\n","(length, width) = map(int, input().split())\narea = length * width\ndominos = 2\nprint(int(area / dominos))\n","(k, l) = list(map(int, input().rstrip().split()))\nprint(k * l // 2)\n","board = input().split()\nlength_board = int(board[0])\nbreadth_board = int(board[1])\narea = length_board * breadth_board\ndomino_area = 2\nprint(area // domino_area)\n","import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, copy, functools\nsys.setrecursionlimit(10 ** 7)\ninf = 10 ** 20\neps = 1.0 / 10 ** 10\nmod = 10 ** 9 + 7\ndd = [(-1, 0), (0, 1), (1, 0), (0, -1)]\nddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]\n\ndef LI():\n\treturn [int(x) for x in sys.stdin.readline().split()]\n\ndef LI_():\n\treturn [int(x) - 1 for x in sys.stdin.readline().split()]\n\ndef LF():\n\treturn [float(x) for x in sys.stdin.readline().split()]\n\ndef LS():\n\treturn sys.stdin.readline().split()\n\ndef I():\n\treturn int(sys.stdin.readline())\n\ndef F():\n\treturn float(sys.stdin.readline())\n\ndef S():\n\treturn input()\n\ndef pf(s):\n\treturn print(s, flush=True)\n\ndef main():\n\t(n, m) = LI()\n\treturn n * m // 2\nprint(main())\n","(m, n) = map(int, input().split())\nc = m * n\nh = c // 2\nprint(h)\n","mn = input()\n(m, n) = mn.split()\nm = int(m)\nn = int(n)\ndominosNumber = int(m * n / 2)\nprint(dominosNumber)\n","(M, N) = input().split()\nDs = 2\nprint(int(M) * int(N) // Ds)\n","import math\nline = input()\nnum = line.split()\na = int(num[0])\nb = int(num[1])\nprint(math.floor(a * b / 2))\n","s = input()\nl = s.split()\nl[0] = int(l[0])\nl[1] = int(l[1])\nprint(int(l[0] * l[1] / 2))\n","m_n = input().split(' ')\nm = int(m_n[0])\nn = int(m_n[1])\nif m % 2 != 0 and n % 2 != 0:\n\tsuma_total = m // 2 * n + n // 2\nelse:\n\tsuma_total = m / 2 * n\nprint(int(suma_total))\n","(n, m) = map(int, input().split())\nS = n * m\nprint('{0:.0f}'.format(S // 2))\n","(m, n) = [int(x) for x in input().split()]\nT = 2\nprint(m * n // T)\n","(n, m) = map(int, input().split())\nr = n * m\nk = 2\nprint(r // 2)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\ns = a * b\nf = s // 2\nprint(f)\n","(m, n) = list(map(int, input().rstrip().split()))\nresult = m * n // 2\nprint(result)\n","import sys\nimport math\n\ndef main():\n\t(M, N) = [int(x) for x in input().split()]\n\tprint(math.floor(M * N / 2))\nmain()\n","from math import floor\ninput = list(map(int, input().strip().split()))\narea = input[0] * input[1]\nprint(floor(area / 2))\n","(m, n) = map(int, input().split(' '))\npiece = 2 * 1\narea = m * n\ndomino = area / piece\ndomino = int(domino)\nprint(domino)\n","(m, n) = map(int, input().split())\narea = m * n\nresult = int(area / 2)\nprint(result)\n","(a, b) = map(int, input().split())\nboard = a * b\nresultado = board / 2\nif board % 2 == 0:\n\tprint(int(resultado))\nif board % 2 == 1:\n\tprint(int(resultado - 0.5))\n","(m, n) = map(int, input().split())\nif m % 2 == 0 and n % 2 == 0:\n\tk = m // 2\n\ts = k * n\n\tprint(s)\nelif m == 2:\n\tk = m - 1\n\ts = k * n\n\tprint(s)\nelif n == 2:\n\tk = n - 1\n\ts = k * m\n\tprint(s)\nelif m % 2 != 0 and n % 2 == 0:\n\tk = (m - 1) // 2\n\ts = k * n\n\th = n // 2\n\tprint(s + h)\nelif m % 2 == 0 and n % 2 != 0:\n\tk = (n - 1) // 2\n\ts = k * m\n\th = m // 2\n\tprint(s + h)\nelif m % 2 != 0 and n % 2 != 0:\n\tk = m - 1\n\tj = n - 1\n\ts = k * j // 2\n\th = n // 2\n\ty = m // 2\n\tprint(s + h + y)\n","p = input().split()\nm = int(p[0])\nn = int(p[1])\ns = m * n\nt = int(s / 2)\nprint(t)\n","from sys import stdin, stdout\n\ndef main():\n\t(m, n) = map(int, stdin.readline().rstrip().split())\n\tdominoNumber = 0\n\tif m % 2 == 0 and n % 2 == 0:\n\t\tdominoNumber = int(m * n / 2)\n\telif m % 2:\n\t\tdominoNumber = int(m / 2 * n)\n\telif n % 2:\n\t\tdominoNumber = int(m * (n / 2))\n\telse:\n\t\tdominoNumber = int(m / 2) * n + int(n / 2)\n\tstdout.write(str(dominoNumber) + '\\n')\nmain()\n","x = input()\na = x.split()\naside = int(a[0])\nbside = int(a[1])\nboard = aside * bside\nprint(board // 2)\n","(l, b) = input().split()\n(l, b) = (int(l), int(b))\nprint(l * b // 2)\n","lst = [int(i) for i in input().split()]\nans = lst[0] * lst[1]\nans = int(ans / 2)\nprint(ans)\n","(a, b) = input().split()\n(a, b) = (int(a), int(b))\nk = int(0)\nwhile a != 0 and b != 0 and (a * b > 1):\n\tif b > a:\n\t\ta = a + b\n\t\tb = a - b\n\t\ta = a - b\n\tk += b\n\ta -= 2\nprint(k)\n","import math\n\ndef solve(m, n):\n\treturn math.floor(m * n * 0.5)\n(n, k) = map(int, input().split(' '))\nc = solve(n, k)\nprint(c)\n","q = input()\nlist1 = q.split(' ')\nf = []\nfor i in list1:\n\tf.append(int(i))\nt = f[0] * f[1]\nprint(t // 2)\n","b = list(map(int, input().split()))\nif b[0] % 2 == 0 or b[1] % 2 == 0:\n\tprint(b[0] * b[1] // 2)\nelif b[0] > 1:\n\tprint((b[0] - 1) * b[1] // 2 + b[1] // 2)\nelif b[1] > 1:\n\tprint(b[0] * (b[1] - 1) // 2 + b[0] // 2)\nelif b[1] == b[0] == 1:\n\tprint(0)\n","(m, n) = map(int, input().split(' '))\nk = m // 2\nm = m - k * 2\ncount = n * k\nif m != 0:\n\tcount += n // 2\nprint(count)\n","sz = input()\nn = sz.split()\nsq = int(n[0]) * int(n[1])\nprint(int(sq / 2))\n","class Solution(object):\n\n\tdef __init__(self):\n\t\t(self.m, self.n) = map(int, input().split())\n\t\trows = cols = 0\n\t\tans = 0\n\t\tif self.m & 1 and self.n & 1:\n\t\t\trows = self.m\n\t\t\tcols = self.n - 1\n\t\t\tans += rows // 2\n\t\telif self.m & 1:\n\t\t\tcols = self.n\n\t\t\trows = self.m\n\t\telse:\n\t\t\tcols = self.m\n\t\t\trows = self.n\n\t\tans += rows * (cols // 2)\n\t\tprint(ans)\n\tpass\n\ndef main():\n\tSolution()\n\tpass\nmain()\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m * n % 2 == 0:\n\tanswer = m * n / 2\nelse:\n\tanswer = int(m * n / 2)\nprint(int(answer))\n","import math as mt\n(m, n) = map(int, input().strip().split())\nres = mt.floor(m / 2 * n)\nprint(res)\n","rectBoard = input().split()\nvert = int(rectBoard[0])\nhoriz = int(rectBoard[1])\nif horiz * vert % 2 == 0:\n\tprint(int(vert * horiz / 2))\nelse:\n\tprint(int((horiz * vert + 1) / 2) - 1)\n","import sys\nfor (i, line) in enumerate(sys.stdin):\n\tif i == 0:\n\t\t(M, N) = (int(line.strip().split(' ')[0]), int(line.strip().split(' ')[1]))\n\t\tprint(M * N // 2)\n","z = input().split(' ')\nx = int(z[0])\ny = int(z[1])\nif x % 2 == 0 and y % 2 == 0 and (x > 1 or y > 1):\n\tprint(int(x * y / 2))\nelif x % 2 != 0 and y % 2 != 0 and (x > 1 or y > 1):\n\tprint(int(x * (y - 1) / 2 + (x - 1) / 2))\nelif x % 2 != 0 and y % 2 == 0 or ((x % 2 == 0 and y % 2 != 0) and (x > 1 or y > 1)):\n\tprint(int(x * y / 2))\nelif x < 2 and y < 2:\n\tprint(0)\n","(z, zz) = (input, lambda : list(map(int, z().split())))\nzzz = lambda : [int(i) for i in stdin.readline().split()]\n(szz, graph, mod, szzz) = (lambda : sorted(zz()), {}, 10 ** 9 + 7, lambda : sorted(zzz()))\nfrom string import *\nfrom re import *\nfrom collections import *\nfrom queue import *\nfrom sys import *\nfrom collections import *\nfrom math import *\nfrom heapq import *\nfrom itertools import *\nfrom bisect import *\nfrom collections import Counter as cc\nfrom math import factorial as f\nfrom bisect import bisect as bs\nfrom bisect import bisect_left as bsl\nfrom itertools import accumulate as ac\nfrom itertools import permutations as permu\n\ndef lcd(xnum1, xnum2):\n\treturn xnum1 * xnum2 // gcd(xnum1, xnum2)\n\ndef prime(x):\n\tp = ceil(x ** 0.5) + 1\n\tfor i in range(2, p):\n\t\tif x % i == 0 and x != 2 or x == 0:\n\t\t\treturn 0\n\treturn 1\n\ndef dfs(u, visit, graph):\n\tvisit[u] = True\n\tfor i in graph[u]:\n\t\tif not visit[i]:\n\t\t\tdfs(i, visit, graph)\n(n, m) = zz()\nt = n * m\nprint(t // 2)\n","(m1, n1) = input().split()\nm = int(m1)\nn = int(n1)\nprint(int(m * n / 2))\n","s = input()\ninput_lists = s.split(' ')\nmatrix = [int(x.strip()) for x in input_lists]\ndomino = 2\nmatrix = matrix[0] * matrix[-1]\nMaximum = matrix / domino\nprint(int(Maximum))\n","a = [int(i) for i in input().split()]\nif a[0] % 2 == 0 and a[1] % 2 == 0:\n\ts = a[1] * (a[0] // 2)\nelif a[0] % 2 == 0 and a[1] % 2 != 0:\n\ts = a[1] * (a[0] // 2)\nelif a[0] % 2 != 0 and a[1] % 2 == 0:\n\ts = a[0] * (a[1] // 2)\nelif a[0] % 2 != 0 and a[1] % 2 != 0:\n\ts = a[1] * (a[0] // 2) + a[1] // 2\nprint(s)\n","def domino():\n\t(M, N) = [int(i) for i in input().split()]\n\tX = M * N // 2\n\tprint(X)\ndomino()\n","import math\nmn = str.split(input())\nm = int(mn[0])\nn = int(mn[1])\nif 1 <= m <= n <= 16:\n\tif m % 2 == 1:\n\t\tx = math.floor(m / 2) * n\n\t\ty = math.floor(n / 2)\n\t\tprint(x + y)\n\telse:\n\t\tx = int(m / 2 * n)\n\t\tprint(x)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nif M % 2 == 0:\n\tx = M // 2 * N\nelif N % 2 == 0:\n\tx = N // 2 * M\nelif M % 2 != 0 and N % 2 != 0:\n\tx = M // 2 * N + N // 2\nprint(x)\n","import sys\n(a, b) = map(int, sys.stdin.readline().split())\ns = a // 2 * b\nif a % 2 != 0:\n\ts += b // 2\nprint(s)\n","inp = input().split()\nprint(int(inp[0]) * int(inp[1]) // 2, sep='', end='\\n')\n","(m, n) = map(int, input().split())\narea_of_domino = 2 * 1\ndomino_number = 0\nif m * n % 2 == 0:\n\tdomino_number = m * n / area_of_domino\nelse:\n\tdomino_number = m * n // area_of_domino\nprint(int(domino_number))\n","n = input()\nm = n.split(' ')\nx = int(m[0])\ny = int(m[1])\na = 2\nprint(x * y // a)\n","w = input().split()\na = int(w[0])\nb = int(w[1])\nc = a * b\nd = int(c / 2)\nprint(d)\n","(m, n) = [int(x) for x in input().split(' ')]\nv = m // 2 * n + m % 2 * n // 2\nh = n // 2 * m + n % 2 * m // 2\nprint(max(h, v))\n","(a, b) = map(int, input().strip().split(' '))\nz = int(a * b / 2)\nprint(z)\n","import math\ncode = input()\n(a, b) = code.split(' ')\na = int(a)\nb = int(b)\nresult = a * b // 2\nresult = math.ceil(result)\nprint(result)\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\nx = m * n\ny = math.floor(x / 2)\nprint(y)\n","(m, n) = tuple(map(int, input().strip().split(' ')))\nprint(m * n // 2)\n","try:\n\t(m, n) = list(map(int, input().split()))\n\tif (m >= 1) & (m <= n):\n\t\tif n <= 16:\n\t\t\tprint(int(m * n / 2))\nexcept ValueError as error:\n\tpass\n","(m, n) = map(int, input().split())\nd = 2 * 1\na = m * n\nq = a // d\nprint(q)\n","(a, s) = map(int, input().split())\nd = a * s\nprint(d // 2)\n","(m, n) = [int(x) for x in input().split(' ')]\nplaced = 0\nif m >= 2 and n >= 1:\n\tplaceVertically = m // 2 * n\n\tverticalRemainder = m % 2\n\tif verticalRemainder:\n\t\tplaceVertically += n // 2\n\tplaced = placeVertically\nelif m >= 1 and n >= 2:\n\tplaceHorizontally = n // 2 * m\n\thorizontalRemainder = n % 2\n\tif horizontalRemainder:\n\t\tplaceHorizontally += m // 2\n\tplaced = placeHorizontally\nprint(placed)\n","import sys\nfrom math import sqrt\ninp = sys.stdin.readline\nread = lambda : list(map(int, inp().split()))\n\ndef solve():\n\t(m, n) = read()\n\tprint(m * n // 2)\nsolve()\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ndomino = 2\nif 1 <= m <= 16 and 1 <= n <= 16:\n\tboard = m * n\n\tans = board / domino\n\tprint(int(ans))\n","(i, k) = map(int, input().split())\nprint(i * k // 2)\n","x = input()\nlst = list(x.split(' '))\nboard = 1\nfor i in lst:\n\tboard *= int(i)\nprint(int(board / 2))\n","(m, n) = list(map(int, input().strip().split(' ')))\nif m == 1 or n == 1:\n\tprint(max(m, n) // 2)\nelse:\n\tdominoes = m // 2\n\tdominoes *= n\n\tif m & 1:\n\t\tdominoes += n // 2\n\tprint(dominoes)\n","(m, n) = [int(x) for x in input().split()]\na = []\na = [[1] * n for i in range(m)]\ncounter = 0\nfor i in range(m - 1):\n\tfor j in range(n):\n\t\tif a[i][j] == 1 and a[i + 1][j] == 1:\n\t\t\tcounter += 1\n\t\t\ta[i][j] = 0\n\t\t\ta[i + 1][j] = 0\nfor i in range(m):\n\tfor j in range(n - 1):\n\t\tif a[i][j] == 1 and a[i][j + 1] == 1:\n\t\t\tcounter += 1\n\t\t\ta[i][j] = 0\n\t\t\ta[i][j + 1] = 0\nprint(counter)\n","size = input().split(' ')\nm = int(size[0])\nn = int(size[1])\nif m % 2 == 0:\n\tdominos = m / 2 * n\nelif n % 2 == 0:\n\tdominos = n / 2 * m\nelse:\n\tdominos = (m - 1) * n / 2 + (n - 1) / 2\nprint(int(dominos))\n","import math\ninput1 = input()\nl1 = input1.split(' ')\nl1 = [int(i) for i in l1]\nans = l1[0] * l1[1] * 0.5\nprint(math.floor(ans))\n","var = input()\n(n, m) = map(int, var.split())\ndom = 0\nif n % 2 == 0:\n\tdom = n / 2 * m\nelse:\n\tdom = n // 2 * m + m // 2\nprint(int(dom))\n","result = 0\ndomino_area = 0\ninputs = input().split(' ')\narea = int(inputs[0]) * int(inputs[1])\nwhile True:\n\tif domino_area > area:\n\t\tresult -= 1\n\t\tbreak\n\tif domino_area == area:\n\t\tbreak\n\telse:\n\t\tresult += 1\n\t\tdomino_area += 2\nprint(result)\n","(l, b) = map(int, input().split())\nt = l * b\nif t % 2 == 0:\n\tO = t // 2\nelse:\n\tt -= 1\n\tO = t // 2\nprint(O)\n","(l, w) = [int(x) for x in input().split()]\nprint(l * w // 2)\n","def dominos(x, y):\n\tif x % 2 == 0 or y % 2 == 0:\n\t\treturn x * y / 2\n\telse:\n\t\treturn ((x - 1) * (y - 1) + (x - 1) + (y - 1)) / 2\n(m, n) = input().split(' ')\nprint(int(dominos(int(m), int(n))))\n","import math\n(n, k) = [int(x) for x in input().split()]\nt = n * k\nprint(t // 2)\n","(m, n) = map(int, input().strip().split())\nsol = int(n / 2) * m\nif n % 2 != 0:\n\tsol = sol + int(m / 2)\nprint(sol)\n","def _50A(m, n):\n\treturn m * n // 2\n(m, n) = list(map(lambda x: int(x), input().split()))\nprint(_50A(m, n))\n","(m, n) = map(int, input().split())\ncount = 0\nwhile m - 2 >= 0:\n\tcount += 1\n\tm -= 2\ncount *= n\nif m != 0:\n\twhile n - 2 >= 0:\n\t\tcount += 1\n\t\tn -= 2\nprint(count)\n","(x, y) = [int(x) for x in input().split()]\nans = x * y / 2\nprint(int(ans))\n","n = input().split(' ')\nfor i in range(2):\n\tn[i] = int(n[i])\nprint(int(n[0] * n[1] / 2))\n","Cadena = input()\nL = Cadena.split()\nM = int(L[0])\nN = int(L[1])\nif N % 2 == 0:\n\tprint(N // 2 * M)\nelse:\n\tprint(N // 2 * M + M // 2)\n","dx = 1\ndy = 2\n(m, n) = map(lambda x: int(x), input().split(' '))\nif m < 0 or n < 0:\n\tprint(0)\n\texit(-1)\nprint(int(m * n / 2))\n","(a, b) = (int(x) for x in input().split())\ni = 0\nif a % 2 == 1 and b % 2 == 1:\n\ta -= 1\n\ti = 1\nn = a * b // 2\nprint((n, n + b // 2)[i > 0])\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nif M % 2 == 0:\n\tans = M // 2 * N\nelse:\n\tans = M // 2 * N + N // 2\nprint(ans)\n","(x, y) = map(int, input().split())\nc = int(x * y // 2)\nprint(c)\n","nm = input().rstrip().split()\nn = int(nm[0])\nm = int(nm[1])\nprint(int(n * m / 2))\n","from math import floor\n\ndef main():\n\t(m, n) = map(int, input().split())\n\ta = m * n\n\tprint(floor(a / 2))\nmain()\n","q = list(map(int, input().split()))\nM = q[0]\nN = q[-1]\nprint(N * M // 2)\n","a = [int(x) for x in input().split()]\nm = a[0]\nn = a[1]\nl = m * n\nif l % 2 == 0:\n\tprint(int(l / 2))\nelse:\n\tprint(int((l - 1) / 2))\n","(m, n) = map(int, input().split())\narea = m * n\np = area // 2\nprint(p)\n","a = [int(i) for i in input().split()]\nm = a[0]\nn = a[1]\nans = int(int(m * n) / 2)\nprint(str(ans))\n","M = list(map(int, input().split()))\nm = M[0]\nn = M[1]\na = m * n\nb = a // 2\nprint(b)\n","(m, n) = map(int, input().split())\nm_max = max(m, n)\nm_min = min(m, n)\nres = m_max * (m_min // 2) + m_min % 2 * (m_max // 2)\nprint(res)\n","import math\narr = input().split(' ')\nn = int(arr[0])\nm = int(arr[1])\nif n * m % 2 == 0:\n\tprint(int(n * m / 2))\nelse:\n\tprint(int(math.floor(n * m / 2)))\n","(m, n) = tuple((int(it) for it in input().split()))\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\nsize = m * n\nnumOfDice = 0\ndiceSpace = 0\nwhile diceSpace <= size:\n\tnumOfDice += 1\n\tdiceSpace += 2\nif diceSpace > size:\n\tdiceSpace -= 2\n\tnumOfDice -= 1\nprint(numOfDice)\n","import math\n\ndef solve(m, n):\n\tprint(math.floor(m * n / 2))\nx = list(map(int, input().split()))\nsolve(x[0], x[1])\n","board_size = input().split(' ')\nboard_size = int(board_size[0]) * int(board_size[1])\nprint(board_size // 2)\n","import math\n\ndef main():\n\t(m, n) = [int(x) for x in input().split()]\n\tif m % 2 == 0 or n % 2 == 0:\n\t\tprint(math.floor(m * n / 2))\n\telse:\n\t\tprint(math.floor((m * n - 1) / 2))\nmain()\n","m_n = input()\nliste = m_n.split(' ')\nm = int(liste[0])\nn = int(liste[1])\nminimum = min(m, n)\nmaximum = max(m, n)\nif maximum % 2 == 0:\n\tprint(maximum // 2 * minimum)\nelse:\n\tprint(maximum // 2 * minimum + minimum // 2)\n","x = input()\nz = x.split()\nz = [int(i) for i in z]\nx = z[0]\ny = z[1]\nprint(int(x * y / 2))\n","(a, b) = map(int, input().split())\nn = a * b // 2\nprint(n)\n","nm = input()\narrinp = nm.split()\nn = int(arrinp[0])\nm = int(arrinp[1])\nprint(n * m // 2)\n","import math\ninput_list = input().split()\na = int(input_list[0])\nb = int(input_list[1])\na_volumen = math.floor(a / 2)\nb_volumen = a_volumen * b\ngesamt_volumen = b_volumen\nif a % 2 == 1:\n\tgesamt_volumen = b_volumen + math.floor(b / 2)\nprint(int(gesamt_volumen))\n","from sys import stdin\ninput = stdin.readline\n\ndef domin(m, n):\n\treturn n * (m >> 1) + (m & 1) * (n >> 1)\nprint(domin(*map(int, input().split())))\n","input_data = input().split()\nm = int(input_data[0])\nn = int(input_data[1])\ns = m * n // 2\nprint(round(s))\n","def floor(n):\n\tres = int(n)\n\treturn res if res == n or n >= 0 else res - 1\nline = input().split()\nm = int(line[0])\nn = int(line[1])\nanswer = floor(m * n * 0.5)\nprint(str(answer))\n","def main():\n\ti = input().split()\n\tprint(int(i[0]) * int(i[1]) // 2)\nmain()\n","def dominoes(table):\n\treturn int(table[0]) * int(table[1]) // 2\nprint(dominoes(input().split(' ')))\n","MN = input().split()\nA = int(MN[0]) * int(MN[1])\na = 2\nres = 0\nwhile A >= a:\n\tA -= a\n\tres += 1\nprint(int(res))\n","(m, n) = map(int, input().split())\nprint([(n * m - 1) // 2, n * m // 2][m % 2 == 0 or n % 2 == 0])\n","sides = input()\nlengths = sides.split(' ')\na = int(lengths[0])\nb = int(lengths[1])\nif 1 <= a <= 16 and 1 <= b <= 16:\n\tarea = a * b\n\tdominocount = area // 2\nprint(dominocount)\n","n = input().split()\nd1 = int(n[0])\nd2 = int(n[1])\nm = d1 * d2\nprint(m // 2)\n","import math\ni = input().split()\nr = 0\nfor x in range(len(i)):\n\ti[x] = int(i[x])\nn = i[0]\nm = i[1]\nr = math.floor(n / 2) * m + n % 2 * math.floor(m / 2)\nprint(r)\n","sum = 0\nline = input()\n(M, N) = line.split()\nm = int(M)\nn = int(N)\nx = m // 2\nsum = sum + n * x\nif m % 2 == 1:\n\tsum = sum + n // 2\nprint(sum)\n","(m, n) = list(map(int, input('').split(' ')))\ncount = 0\nif m >= 1:\n\tif n % 2 != 0:\n\t\tcount = n // 2 * m\n\t\trem = n - n // 2\n\t\tif rem >= 1:\n\t\t\tcount += m // 2\n\t\tprint(count)\n\telse:\n\t\tprint(n // 2 * m)\nelse:\n\tprint(0)\n","p = input().split(' ')\nif int(p[0]) >= 1 and int(p[0]) <= int(p[1]) and (int(p[1]) <= 16):\n\ta = int(p[0]) * int(p[1])\n\tif a == 1:\n\t\tprint('0')\n\telif a >= 2:\n\t\tb = int(a / 2)\n\t\tprint(b)\n","l = list(map(int, input().split()))\nm = l[0]\nn = l[1]\nto_num = m * n\nprint(to_num // 2)\n","import math\n(m, n) = [int(x) for x in input().split()]\ns = m * n\nd = 2 * 1\nprint(math.floor(s / d))\n","def domino_piling():\n\tmn = str(input())\n\ti = mn.find(' ')\n\tm = int(mn[:i])\n\tn = int(mn[i + 1:])\n\tif m % 2 == 0 and n % 2 == 0:\n\t\tprint(int(m * n / 2))\n\t\treturn\n\tif m % 2 != 0 and n % 2 != 0:\n\t\tprint(int(m * (n - 1) / 2 + (m - 1) / 2))\n\t\treturn\n\tprint(int(m * n / 2))\ndomino_piling()\n","[a, b] = [int(i) for i in input().split()]\ns = a * b\nkol = s // 2\nprint(kol)\n","a = input().split(' ')\nn = int(a[0])\nk = int(a[1])\nb = n * k\nif b % 2 == 0:\n\tprint(int(b / 2))\nelse:\n\tprint(int((b - 1) / 2))\n","mn = input().split()\ns = int(mn[0]) * int(mn[1])\nresult = s // 2\nprint(result)\n","(n, m) = [int(x) for x in input().split()]\nt = 0\nwhile t * 2 < n * m:\n\tif (t + 1) * 2 > n * m:\n\t\tbreak\n\tt += 1\nprint(t)\n","import math\n\ndef domino_piling(m, n):\n\tprint(int(m * n / 2))\n(m, n) = map(int, input().split())\ndomino_piling(m, n)\n","n = list(map(int, input().split()))\nans = n[0] * n[1] // 2\nprint(ans)\n","(l, w) = input().split()\narea = int(l) * int(w)\nif area % 2 == 0:\n\tans = int(area / 2)\nelse:\n\tans = int((area - 1) / 2)\nprint(ans)\n","(m, n) = map(int, input().split())\nk = 0\nl = 2\nwhile m * n >= l:\n\tl += 2\n\tk += 1\nprint(k)\n","(n, m) = input().strip('\\n\\r\\t ').split(' ')\nn = int(n)\nm = int(m)\nif m % 2 == 1 and n % 2 == 1:\n\tprint((m * n - 1) // 2)\nelse:\n\tprint(m * n // 2)\n","def domino_piling():\n\t(M, N) = input().split()\n\t(M, N) = (int(M), int(N))\n\tcount = M * N // 2\n\tprint(str(int(count)))\ndomino_piling()\n","(m, n) = [int(i) for i in input().split()]\na = 2\nb = 1\ny = 0\nz = 0\nx = 0\ny = m * n\nz = a * b\nx = y // z\nprint(x)\n","def process(x, y):\n\treturn x * y // 2\nn = [int(x) for x in input().split()]\nx = process(n[0], n[1])\nprint(x)\n","from __future__ import division, print_function\nfrom fractions import Fraction\nimport sys\nimport os\nfrom io import BytesIO, IOBase\nfrom itertools import *\nimport bisect\nfrom heapq import *\nfrom math import *\nfrom copy import *\nfrom collections import deque\nfrom collections import Counter as counter\nfrom itertools import combinations as comb\nfrom itertools import permutations as permutate\nfrom bisect import bisect_left as bl\nfrom bisect import bisect_right as br\nfrom bisect import bisect\nBUFSIZE = 8192\n\nclass FastIO(IOBase):\n\tnewlines = 0\n\n\tdef __init__(self, file):\n\t\tself._fd = file.fileno()\n\t\tself.buffer = BytesIO()\n\t\tself.writable = 'x' in file.mode or 'r' not in file.mode\n\t\tself.write = self.buffer.write if self.writable else None\n\n\tdef read(self):\n\t\twhile True:\n\t\t\tb = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))\n\t\t\tif not b:\n\t\t\t\tbreak\n\t\t\tptr = self.buffer.tell()\n\t\t\t(self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr))\n\t\tself.newlines = 0\n\t\treturn self.buffer.read()\n\n\tdef readline(self):\n\t\twhile self.newlines == 0:\n\t\t\tb = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))\n\t\t\tself.newlines = b.count(b'\\n') + (not b)\n\t\t\tptr = self.buffer.tell()\n\t\t\t(self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr))\n\t\tself.newlines -= 1\n\t\treturn self.buffer.readline()\n\n\tdef flush(self):\n\t\tif self.writable:\n\t\t\tos.write(self._fd, self.buffer.getvalue())\n\t\t\t(self.buffer.truncate(0), self.buffer.seek(0))\n\nclass IOWrapper(IOBase):\n\n\tdef __init__(self, file):\n\t\tself.buffer = FastIO(file)\n\t\tself.flush = self.buffer.flush\n\t\tself.writable = self.buffer.writable\n\t\tself.write = lambda s: self.buffer.write(s.encode('ascii'))\n\t\tself.read = lambda : self.buffer.read().decode('ascii')\n\t\tself.readline = lambda : self.buffer.readline().decode('ascii')\n\ndef print(*args, **kwargs):\n\t(sep, file) = (kwargs.pop('sep', ' '), kwargs.pop('file', sys.stdout))\n\tat_start = True\n\tfor x in args:\n\t\tif not at_start:\n\t\t\tfile.write(sep)\n\t\tfile.write(str(x))\n\t\tat_start = False\n\tfile.write(kwargs.pop('end', '\\n'))\n\tif kwargs.pop('flush', False):\n\t\tfile.flush()\nif sys.version_info[0] < 3:\n\t(sys.stdin, sys.stdout) = (FastIO(sys.stdin), FastIO(sys.stdout))\nelse:\n\t(sys.stdin, sys.stdout) = (IOWrapper(sys.stdin), IOWrapper(sys.stdout))\nfrom types import GeneratorType\n\ndef iterative(f, stack=[]):\n\n\tdef wrapped_func(*args, **kwargs):\n\t\tif stack:\n\t\t\treturn f(*args, **kwargs)\n\t\tto = f(*args, **kwargs)\n\t\twhile True:\n\t\t\tif type(to) is GeneratorType:\n\t\t\t\tstack.append(to)\n\t\t\t\tto = next(to)\n\t\t\t\tcontinue\n\t\t\tstack.pop()\n\t\t\tif not stack:\n\t\t\t\tbreak\n\t\t\tto = stack[-1].send(to)\n\t\treturn to\n\treturn wrapped_func\nmod = 1000000007\n\ndef inp():\n\treturn sys.stdin.readline().rstrip('\\r\\n')\n\ndef out(var):\n\tsys.stdout.write(str(var))\n\ndef lis():\n\treturn list(map(int, inp().split()))\n\ndef stringlis():\n\treturn list(map(str, inp().split()))\n\ndef sep():\n\treturn map(int, inp().split())\n\ndef strsep():\n\treturn map(str, inp().split())\n\ndef zerolist(n):\n\treturn [0] * n\n\ndef nextline():\n\tout('\\n')\n\ndef testcase(t):\n\tfor p in range(t):\n\t\tsolve()\n\ndef printlist(a):\n\tfor p in range(0, len(a)):\n\t\tout(str(a[p]) + ' ')\n\ndef solve():\n\t(m, n) = sep()\n\tans = m // 2 * n\n\tif m % 2 == 1:\n\t\tans += n // 2\n\tprint(ans)\nsolve()\n","(m, n) = input().split()\nlength = int(m)\nwiedth = int(n)\ndomino = 0\nif length % 2 == 0:\n\tdomino = length // 2 * wiedth\nif wiedth % 2 == 0:\n\tdomino = wiedth // 2 * length\nif length % 2 == 1:\n\tdomino = length // 2 * wiedth + wiedth // 2\nif wiedth % 2 == 1:\n\tdomino = wiedth // 2 * length + length // 2\nprint(domino)\n","(m, n) = map(int, input().split())\nif m % 2 == 0 and n % 2 == 0:\n\tres = m * n // 2\nelif m % 2 == 1 and n % 2 == 1:\n\tres = (m - 1) * (n - 1) / 2 + m // 2 + n // 2\nelse:\n\todd = m if m % 2 == 1 else n\n\teven = n if odd == m else m\n\tres = max(odd * even // 2, even * (odd // 2) + even // 2)\nprint(int(res))\n","w = input()\n(M, N) = w.split(' ')\nif int(M) % 2 == 0 or int(N) % 2 == 0:\n\tr = int(M) * int(N) / 2\nelse:\n\tr = (int(M) - 1) * int(N) / 2 + int(N) // 2\nprint(int(r))\n","(M, N) = map(int, input().split())\nt = M * N\nif t % 2 == 1:\n\tt -= 1\nprint(t // 2)\n","(M, N) = input().split()\nm = int(M)\nn = int(N)\na = m * n\nd = int(a / 2)\nprint(d)\n","A = input().split()\nz = A[0]\nz = int(z)\nx = A[1]\nx = int(x)\nq = x * z // 2\nprint(q)\n","x = input()\nz = x.split()\nm = int(z[0])\nn = int(z[1])\nh = int(m * n // 2)\nprint(h)\n","(squareH, squareL) = map(int, input().split())\ndominoH = 1\ndominoL = 2\nif dominoH > dominoL:\n\t_tmp = dominoH\n\tdominoH = dominoL\n\tdominoL = _tmp\nnumH = squareH // dominoH\nnumL = squareL // dominoL\nnumRotate = int()\nrestL = squareL - numL * dominoL\nif restL / dominoH > 0 and squareH / dominoL > 0:\n\tnumRotate = restL // dominoH * (squareH // dominoL)\ntotal = numH + (numL - 1) * numH + numRotate\nprint(total)\n","(m, n) = input().split()\nif int(m) % 2 == 0:\n\tprint(int(int(m) / 2 * int(n)))\nelse:\n\tt = int(int(m) / 2)\n\tp = int(int(n) / 2)\n\tprint(t * int(n) + p)\n","val = list(map(int, input().split(' ')))\nprint(val[0] * val[1] // 2)\n","token = input()\nasd = token.split()\ntotal = int(asd[0]) * int(asd[-1])\nprint(total // 2)\n","(M, N) = [int(i) for i in input().split()]\nnumber = 0\nif M % 2 == 0:\n\tnumber = M // 2 * N\nelse:\n\tnumber = M // 2 * N + N // 2\nprint(number)\n","(M, N) = map(int, input().strip().split(' '))\ndominos = M * N / 2\nprint(int(dominos))\n","(m, n) = list(map(int, input().split(' ')))\na = int(m / 2)\na = a * n\nif m % 2 == 1:\n\tb = int(n / 2)\n\ta = a + b\nprint(a)\n","x = lambda : map(int, input().split())\n(m, n) = x()\nprint(int(m * n / 2))\n","(n, m) = [int(i) for i in input().split()]\nts = n * m\nprint(ts // 2)\n","import math\n(m, n) = map(int, input().split())\na = 2\nif n >= m and n % 2 == 0:\n\tres = m * round(n / a)\n\tprint(res)\nelif n >= m and n % 2 != 0:\n\tres = m * (n / a)\n\tprint(int(res))\nelse:\n\tres = round(n / a) * round(m / a)\n\tprint(res)\n","(a, b) = map(int, input().split())\nres = int(a * b / 2)\nprint(res)\n","import sys\n(n, m) = map(int, sys.stdin.read().rstrip().split())\nprint(int(n * m // 2))\n","(largura, comprimento) = [int(i) for i in input().split()]\nprint(int(largura * comprimento / 2))\n","first_line = input().split(' ')\nM = int(first_line[0])\nN = int(first_line[1])\ndom_area = 2\nboard_area = M * N\nnum_of_dom = 0\nif board_area % 2 == 0:\n\tnum_of_dom = board_area // dom_area\nelse:\n\tnum_of_dom = (board_area - 1) // dom_area\nprint(num_of_dom)\n","import math\ns = input().split()\nM = int(s[0])\nN = int(s[1])\nprint(math.floor(M * N / 2))\n","def letsee():\n\t(m, n) = map(int, input().split())\n\tif m < 1 or m > 16 or n < 1 or (n > 16):\n\t\treturn\n\tdominos = m * n // 2\n\tprint(dominos)\nletsee()\n","(m, n) = [int(x) for x in input().split()]\ns = m * n\nif s % 2 != 0:\n\ta = s - 1\n\td = int(a / 2)\nelse:\n\td = int(s / 2)\nprint(d)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nhasil = 0\nluas = m * n\nif luas % 2 == 0:\n\thasil = luas / 2\nelse:\n\tluas = luas - 1\n\thasil = luas / 2\nprint(round(hasil), '\\n')\n","def main():\n\tnumbers = input().split()\n\tn = int(numbers[0])\n\tm = int(numbers[1])\n\tres = n * m // 2\n\tprint(res)\nmain()\n","masuk = list(map(int, input().split()))\nA = masuk[0]\nB = masuk[1]\nhasil = int(A * B)\nprint(int(hasil / 2))\n","luso = input()\nM = int(luso.split(' ')[0])\nN = int(luso.split(' ')[1])\nk = 2\nh = M * N\nprint(h // k)\n","data = input()\nminor_arr = str(data).split()\nS = int(minor_arr[0]) * int(minor_arr[1])\ncount = S // 2\nprint(count)\n","(m, n) = map(int, input().split(' '))\npiecearea = 2 * 1\nrecarea = m * n\nres = recarea / piecearea\nres = int(res)\nprint(res)\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\ncnt = 0\nif m % 2 == 0:\n\tcnt = cnt + m / 2 * n\nelif n % 2 == 0:\n\tcnt = cnt + n / 2 * m\nelse:\n\twhile n > 0:\n\t\tcnt = cnt + m / 2\n\t\tn = n - 1\nprint(math.floor(cnt))\n","(M, N) = [int(i) for i in input().split()]\ntotal_area = M * N\nprint(total_area // 2)\n","lst = list(input().strip().split())\nm = int(lst[0])\nn = int(lst[1])\nprint(m * n // 2)\n","string = input().split()\narea = int(string[0]) * int(string[1])\nif area % 2 == 0:\n\tprint(area // 2)\nelse:\n\tprint((area - area % 2) // 2)\n","(width, length) = map(int, input().split())\n\ndef is_even(num):\n\tif num % 2 == 0:\n\t\treturn 'even'\nif is_even(length):\n\tans = int(length / 2 * width)\nelif is_even(width) and (not is_even(length)):\n\tans = int(width / 2 * length)\nx = None\ny = None\nif width == 1 and length == 1:\n\tprint('0')\n\texit()\nif not is_even(length) and (not is_even(width)):\n\tif width >= 2:\n\t\tx = int(width / 2)\n\telif length >= 2:\n\t\ty = int(length / 2)\nif x is not None:\n\tdominoes_across = int(x * length)\n\trem = int(length / 2)\n\tans = dominoes_across + rem\nif y is not None:\n\tdominoes_across = int(y * width)\n\trem = int(width / 2)\n\tans = dominoes_across + rem\nprint(ans)\n","(m, n) = list(map(int, input().split()))\nprint(str(int(m * n / 2)))\n","(n, m) = map(int, input().split())\narea = n * m\narea2 = 2\ncount = area // area2\nprint(count)\n","push = lambda : map(int, input().split())\n(n, m) = push()\nprint(n * m // 2)\n","(a, b) = map(int, input().split())\nc = a * b\nd = c\nf = d - 1\nif c % 2 == 0:\n\tt = int(c / 2)\n\tprint(t)\nelse:\n\tprint(int(f / 2))\n","(m, n) = [int(x) for x in input().split()]\nres = m * n\nout = int(res / 2)\nprint(out)\n","(n, m) = map(int, input().split())\nres = n * m\nres2 = res // 2\nprint(res2)\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\tmax_tiles = m / 2 * n\nelif n % 2 == 0:\n\tmax_tiles = n / 2 * m\nelse:\n\tmax_tiles = m // 2 + n // 2 * m\nprint(int(max_tiles))\n","def main():\n\t(M, N) = map(int, input().split())\n\tboardSize = M * N\n\tdominoSize = 2\n\tnumberOfDominus = int(boardSize / dominoSize)\n\tprint(numberOfDominus)\nmain()\n","(m, n) = input().split()\narea = int(m) * int(n)\nnumber = area // (2 * 1)\nprint(number)\n","(r, c) = map(int, input().split(' '))\nnum = 0\nif r % 2 == 0:\n\tnum = int(r / 2) * c\nelse:\n\tnum = int(r / 2) * c + int(c / 2)\nprint(num)\n","(m, n) = list(map(int, input().strip().split()))\nanswer = m * n // 2\nprint(answer)\n","temp = input().split(' ')\nm = int(temp[0])\nn = int(temp[1])\nprint(m * n // 2)\n","(a, b) = map(int, input().split())\nif a * b % 2 == 0:\n\tprint(a * b // 2)\nelse:\n\timport math\n\tprint(math.floor(a * b // 2))\n","def main(stuff):\n\t(m, n) = stuff\n\t(m, n) = (int(m), int(n))\n\tif m % 2 != 0 and n % 2 != 0:\n\t\tprint(int((m * n - 1) / 2))\n\telse:\n\t\tprint(int(m * n / 2))\nmain(input().split())\n","lst_of_numbers = [int(x) for x in input().split()]\nprint(lst_of_numbers[0] * lst_of_numbers[1] // 2)\n","(w, h) = map(int, input().split())\nif w % 2 == h % 2 == 0:\n\tprint(int(w / 2 * h))\nelif w % 2 == h % 2 == 1:\n\tprint(int((w - 1) / 2 * h + (h - 1) / 2))\nelif not w % 2 == h % 2:\n\tprint(int(h * w / 2))\n","import math\n(a, b) = map(int, input().split())\n(am, bm) = (a % 2, b % 2)\nif am and bm:\n\tprint(int(((a - 1) * (b - 1) + a + b - 1) / 2))\nif not am and (not bm):\n\tprint(int(a * b / 2))\nif am and (not bm):\n\tprint(int(((a - 1) * b + b) / 2))\nif not am and bm:\n\tprint(int((a * (b - 1) + a) / 2))\n","import math\n(M, N) = input().split(' ')\nM = int(M)\nN = int(N)\nprint(max(int(M / 2) * N + M % 2 * int(N / 2), int(N / 2) * M + N % 2 * int(M / 2)))\n","raw_arr = str(input()).split()\n(m, n) = (int(raw_arr[0]), int(raw_arr[1]))\ntiles = 0\nif m % 2 == 1 and n % 2 == 1:\n\ttiles = (m * n - 1) / 2\nelse:\n\ttiles = m * n / 2\nprint(str(tiles)[:-2])\n","dimr = input().split()\narea = int(dimr[0]) * int(dimr[1])\nnumber = area / 2\nreal_number = int(number)\nprint(real_number)\n","__author__ = 'DeyerliQiz'\n(n, m) = map(int, input().split())\nprint(int(n * m / 2))\n","l = [int(i) for i in input().split()]\nn1 = l[0]\nn2 = l[1]\ng = n1 * n2\nprint(g // 2)\n","s = list(map(int, input().split()))\nans = int(s[0] * s[1] / 2)\nprint(ans)\n","(rows, cols) = list(map(int, input().split()))\nprint(rows // 2 * cols + cols // 2 * (rows % 2))\n","(a, b) = [int(x) for x in input().strip().split()]\ns = a * (b // 2) + b % 2 * (a // 2)\nprint(s)\n","txt = input()\n(m, n) = [int(i) for i in txt.split('\\n')[0].split(' ')]\nprint(str(m * n // 2))\n","parameter = input()\nm = int(parameter.split()[0])\nn = int(parameter.split()[1])\nnumber = m * n // 2\nprint(number)\n","from sys import stdin, stdout\ninp = [int(x) for x in stdin.read().split()]\nm = inp.pop(0)\nn = inp.pop(0)\nprint(m * n // 2)\n","line = input()\npieces = line.split()\nM = int(pieces[0])\nN = int(pieces[1])\nif M * N % 2 == 0:\n\tn = int(M * N / 2)\nelse:\n\tn = int((M * N - 1) / 2)\nprint(n)\n","def Domino():\n\t(m, n) = input().split()\n\tif int(n) == 1:\n\t\tprint(0)\n\telif int(n) % 2 == 0:\n\t\tprint(int(n) // 2 * int(m))\n\telse:\n\t\ta = int(n) // 2 * int(m)\n\t\tb = int(m) // 2\n\t\tprint(a + b)\nDomino()\n","ar = list(map(int, input().split()))\nprint(ar[0] * ar[1] // 2)\n","inp = input().strip().split()\nm = int(inp[0])\nn = int(inp[1])\nif m % 2 == 0 and n % 2 == 0:\n\tmax1 = m // 2 * n\n\tmax2 = n // 2 * m\n\tif max1 > max2:\n\t\tprint(max1)\n\telse:\n\t\tprint(max2)\nelif m % 2 == 0 and n % 2 != 0:\n\tprint(m // 2 * n)\nelif m % 2 != 0 and n % 2 == 0:\n\tprint(n // 2 * m)\nelse:\n\tmax1 = m // 2 * n + n // 2\n\tmax2 = n // 2 * m + m // 2\n\tif max1 > max2:\n\t\tprint(max1)\n\telse:\n\t\tprint(max2)\n","sides = input().split(' ')\nprint(int(sides[0]) * int(sides[1]) // 2)\n","m_n = [int(i) for i in input().split()]\nprint(m_n[0] * m_n[1] // 2)\n","(m, n) = map(int, input().split())\nArea = m * n\ndomino = Area // 2\nif m < 1 or m > 16 or n < 0 or (n > 19):\n\tpass\nelse:\n\tprint(domino)\n","mn = list(map(int, input().rstrip().split()))\nm = mn[0] * mn[1]\nn = int(m / 2)\nprint(n)\n","def main():\n\t(m, n) = [int(x) for x in input().split()]\n\tprint(int(m * n / 2))\nmain()\n","(m, n) = [int(i) for i in input().split(' ')]\n\ndef recursive(result, curr_m):\n\tif curr_m > 2:\n\t\treturn recursive(result + n, curr_m - 2)\n\telif curr_m == 2:\n\t\treturn result + n\n\telse:\n\t\treturn result + int(n / 2)\nprint(recursive(0, m))\n","inp = input().split()\n(m, n) = (int(inp[0]), int(inp[1]))\nrow = m // 2\nnum = row * n\nif m % 2 == 1:\n\tnum += n // 2\nprint(num)\n","s = input('')\nl = s.split()\nm = int(l[0])\nn = int(l[1])\na = m * n // 2\nprint(a)\n","def max_dominoes(m, n):\n\tarea = m * n\n\tprint(area // 2)\nline1 = input()\narg1 = int(line1.split()[0])\narg2 = int(line1.split()[1])\nmax_dominoes(arg1, arg2)\n","import sys\nfrom collections import Counter as C\n(m, n) = map(int, input().split())\nprint(m * n // 2)\n","(M, N) = map(int, input().split())\nS = M * N\nif S % 2 == 1:\n\tnum = S // 2\nelse:\n\tnum = S / 2\nprint(int(num))\n","import math\nnuminput = str(input())\na = [int(x) for x in numinput.split()]\nsize = a[0] * a[1] / 2\nprint(math.floor(size))\n","(m, n) = map(int, input().split())\ns = m * n\nif s > 0 and s < 2:\n\tprint('0')\nelif s >= 2:\n\tnumbers = int(s / 2)\n\tprint(numbers)\n","l = [input()]\nl = l[0].split(' ')\nm = int(l[0])\nn = int(l[1])\nprint(int(m * n / 4 * 2))\n","def f(m, n):\n\tc = 0\n\tc += m // 2 * n\n\tc += m % 2 * (n // 2)\n\treturn c\n(m, n) = [int(i) for i in input().split()]\nprint(f(m, n))\n","(sirka, vyska) = map(int, input().split())\npoukladane = 0\npoukladane += sirka * (vyska // 2)\nif vyska % 2:\n\tpoukladane += sirka // 2\nprint(poukladane)\n","from collections import Counter\nimport string\nimport math\nimport sys\n\ndef array_int():\n\treturn [int(i) for i in sys.stdin.readline().split()]\n\ndef vary(number_of_variables):\n\tif number_of_variables == 1:\n\t\treturn int(sys.stdin.readline())\n\tif number_of_variables >= 2:\n\t\treturn map(int, sys.stdin.readline().split())\n\ndef makedict(var):\n\treturn dict(Counter(var))\nmod = 100000007\n(m, n) = vary(2)\nans = 0\nif n % 2 == 0:\n\tans += n // 2 * m\nelse:\n\tans += m * (n - 1) // 2\n\tif m % 2 == 0:\n\t\tans += m // 2\n\telse:\n\t\tans += (m - 1) // 2\nprint(ans)\n","(m, n) = [int(i) for i in input().split()]\narea = m * n\nprint(int(area / 2))\n","(m, n) = list(map(int, input().split(' ')))\n(tmp1, tmp2, ans) = (0, 0, 0)\ntmp1 = m // 2\nans = tmp1 * n\ntmp2 = m % 2\nif tmp2 == 1:\n\tans += n // 2\nprint(ans)\n","import math\n(width, length) = list(map(int, input().split(' ')))\nprint(math.floor(width * length / 2))\n","(a, b) = map(int, input().split())\nc = a * b / (2 * 1)\nprint(int(c))\n","import math\ninput_dimensions = [int(x) for x in input().split(' ')]\nprint(math.floor(input_dimensions[0] * input_dimensions[1] / 2))\n","nk = list(map(int, input().split()))\nsquare = nk[0] * nk[1]\nprint(square // 2)\n","(m, n) = [int(x) for x in input().split()]\nif n % 2 == 1 and m % 2 == 1:\n\tprint((n * m - 1) // 2)\nelif n % 2 == 0 and m % 2 == 0:\n\tprint(n * m // 2)\nelif n % 2 == 0 and m % 2 == 1:\n\tprint(n * m // 2)\nelif n % 2 == 1 and m % 2 == 0:\n\tprint(m * n // 2)\n","(x, y) = map(int, input().split())\nans = int(x / 2) * y\nif not x % 2 == 0:\n\tans += int(y / 2)\nprint(ans)\n","board_dimensions = input()\nn = int(board_dimensions.split(' ')[0])\nm = int(board_dimensions.split(' ')[1])\nboard_size = n * m\n\ndef in_range(n, m):\n\treturn 1 <= n <= 16 and 1 <= m <= 16\nif in_range(n, m) and board_size % 2 == 0:\n\tprint(int(board_size / 2))\nelif in_range(n, m) and board_size % 2 != 0:\n\tprint(int(board_size / 2 - 0.5))\nelse:\n\tprint('Number out of range')\n","x = input()\nnumero = x.split(' ')\nprint(int(numero[0]) * int(numero[1]) // 2)\n","a = input()\nx = a.split()\nn = int(x[0])\nk = int(x[1])\npdt = n * k\nc = pdt / 2\nc = int(c)\nprint(c)\n","(m, n) = map(int, input().split())\ndominoes_overlapped = m * n // 2\nprint(str(dominoes_overlapped))\n","a = input()\ns = ''\nA = []\nfor i in a:\n\tif i == ' ':\n\t\tA.append(int(s))\n\t\ts = ''\n\telse:\n\t\ts += i\nA.append(int(s))\nif A[0] > A[1] or A[1] % 2 == 1:\n\ts = A[0]\n\tA[0] = A[1]\n\tA[1] = s\nif A[0] * A[1] == 1:\n\tprint(0)\nelif A[0] % 2 == 1 == A[1] % 2:\n\tprint(A[1] * (A[0] // 2) + A[1] // 2)\nelif A[0] % 2 != A[1] % 2:\n\tprint(A[0] * (A[1] // 2))\nelse:\n\tprint(A[0] * (A[1] // 2))\n","(m, n) = map(int, input().split())\np = m * n\ndominos = p // 2\nprint(dominos)\n","import math\n\ndef toInteger(x):\n\tfor i in range(len(x)):\n\t\tx[i] = int(x[i])\n\treturn x\n\ndef solve(x):\n\tsquares = x[0] * x[1]\n\treturn math.floor(squares / 2)\nx = toInteger(input().split(' '))\nprint(solve(x))\n","nm = input().split()\nn = int(nm[0])\nm = int(nm[1])\nk = n * m\nif k % 2 == 0:\n\tv = k // 2\n\tprint(v)\nelse:\n\tj = (k - 1) // 2\n\tprint(j)\n","b = input()\nb = b.split()\nb1 = int(b[0])\nb2 = int(b[1])\nb3 = b1 * b2\nrespuesta = b3 // 2\nprint(respuesta)\n","(m, n) = [int(i) for i in input().split()]\nt1 = (m - m % 2) // 2 * n\nt1 += m % 2 * ((n - n % 2) // 2)\nt2 = (n - n % 2) // 2 * m\nt2 += n % 2 * ((m - m % 2) // 2)\nprint(max([t1, t2]))\n","def solve(m, n):\n\ta = m * n\n\treturn a // 2\ninp = input().split(' ')\nm = inp[0]\nn = inp[1]\nprint(solve(int(m), int(n)))\n","import math\nstring = str(input()).split(' ')\nm = int(string[0])\nn = int(string[1])\nprint(int(m / 2 * n / 1))\n","m = input().split()\nM = int(m[0])\nN = int(m[1])\nS = M * N\ns = S // 2\nprint(s)\n","dimentions = [int(x) for x in input().split()]\nlength = dimentions[0]\nwidth = dimentions[1]\narea = length * width\ndinamo_pieces = int(area / 2)\nprint(dinamo_pieces)\n","import math\n(m, n) = (1, 1)\n(m, n) = map(int, input().split())\nd = 2\nsum = 0\nsq = m * n\nif sq % 2 == 0:\n\tprint(int(sq / 2))\nelse:\n\tprint(int((sq - 1) / 2))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ns = m * n\nc = 0\nfor i in range(1, s):\n\tif i * 2 <= s:\n\t\tc = i\n\telse:\n\t\tbreak\nprint(c)\n","import math\n\ndef domino():\n\t(height, width) = list(map(int, input().split()))\n\tresult = math.floor(width / 2 * height)\n\treturn result\nprint(domino())\n","s = input()\ns = s.split(' ')\nM = int(s[0])\nN = int(s[1])\nprint(M * N // 2)\n","given = input()\nm = int(given.split(' ')[0])\nn = int(given.split(' ')[1])\nprint(n * m // 2)\n","import sys\nimport math\n\ndef main():\n\t(m, n) = map(int, sys.stdin.readline().strip().split())\n\tprint(max(m, n) // 2 * min(m, n) + max(m, n) % 2 * min(m, n) // 2)\nmain()\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nboard = m * n\nif m >= 1 and m <= n and (n <= 16):\n\tdivision = board / 2\n\tMax = int(division)\n\tprint(Max)\n","var = input().split()\nx = int(var[0])\ny = int(var[1])\narea = x * y\nif area % 2 == 0:\n\tprint(int(area / 2))\nelse:\n\tprint(int((area - 1) / 2))\n","import sys\ninput = sys.stdin.readline\n\ndef invr():\n\treturn map(int, input().split())\n\ndef domino(v):\n\treturn v // 2\n(m, n) = invr()\no = domino(m * n)\nprint(o)\n","inp = input()\ns = inp.find(' ')\nM = int(inp[:s])\nN = int(inp[s + 1:])\nprint(M * (N // 2) + M // 2 * (N % 2))\n","(M, N) = [int(i) for i in input().split()]\nDominos = M * N // 2\nprint(Dominos)\n","board = list(map(int, input().split()))\nSboard = board[0] * board[1]\nprint(Sboard // 2)\n","(m, n) = map(int, input().split())\na = m * n\nans = int(a / 2)\nprint(ans)\n","x = list(map(int, input().strip().split()))\na = x[0]\nb = x[1]\nprint(a * b // 2)\n","(m, n) = map(int, input().split())\nmilty = int(m * n)\ndiv = milty // 2\nprint(div)\n","(n, k) = map(int, input().split())\nmultiplied = n * k\nprint(multiplied // 2)\n","pl = list(map(int, input().split()))\nluas = pl[0] * pl[1]\nprint(luas // 2)\n","p = [i for i in input().split()]\nfor i in range(len(p)):\n\tp[i] = int(p[i])\nprint(p[0] * p[1] // 2)\n","n = list(map(int, input().split()))\nif n[0] > n[1]:\n\ta = n[0]\n\tb = n[1]\nelse:\n\ta = n[1]\n\tb = n[0]\nif a % 2 == 0:\n\tprint(a // 2 * b)\nelse:\n\tprint(a // 2 * b + b // 2)\n","(m, n) = [int(i) for i in input().split()]\nbourd = m * n\nc = bourd / 2\nprint(int(c))\n","(m, n) = [int(x) for x in input().split()]\nif m == 1 and n == 1:\n\tprint('0')\nelif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\ts = m * n // 2\n\tprint(s)\n","(ms, ns) = input().split()\nm = int(ms)\nn = int(ns)\narea = m * n\ndom = area / 2\ndominos = int(dom)\nprint(dominos)\n","import sys, os.path\nif os.path.exists('input.txt'):\n\tsys.stdin = open('input.txt', 'r')\n\tsys.stdout = open('output.txt', 'w')\n(n, m) = map(int, input().split())\nprint(m * n // 2)\n","(M, N) = [int(i) for i in input().split()]\nprint((M * N - 1) // 2 if M * N % 2 else M * N // 2)\n","(m, n) = map(int, input().split())\n(a, r) = (0, 0)\na = m * n\nr = a // 2\nprint(r)\n","import math\n(m, n) = map(int, input().split())\nk = m / 1\nl = n / 2\nnum = math.floor(k * l)\nprint(num)\n","from math import floor\n\ndef main():\n\tfrom sys import stdout\n\t(m, n) = map(int, input().split())\n\ttotal = m * n\n\tres = floor(total / 2)\n\tstdout.write(str(res))\nmain()\n","size = list(map(int, input().split()))\ns = size[0] * size[1] // 2\nprint(s)\n","(m, n) = list(map(int, input().split(' ')))\nlength = m\nwidth = n\nnumber = 0\nif length < width:\n\tlength = n\n\twidth = m\nwhile length != 1 or width != 1:\n\tif length < width:\n\t\tmid = width\n\t\twidth = length\n\t\tlength = mid\n\tif length >= 2:\n\t\tnumber += width * (length // 2)\n\t\tlength = length % 2\n\t\tif length == 0:\n\t\t\tbreak\nprint(number)\n","(m, n) = list(map(int, input().split()))\ncount = 0\nif m >= 2:\n\trow = m\n\twhile row >= 2:\n\t\tfor i in range(0, n):\n\t\t\tcount += 1\n\t\trow -= 2\n\tif m % 2 != 0:\n\t\tif n % 2 == 0:\n\t\t\tcount += n / 2\n\t\telse:\n\t\t\tcount += (n - 1) / 2\nelif n % 2 == 0:\n\tcount += n / 2\nelse:\n\tcount += (n - 1) / 2\nprint(int(count))\n","mn = list(map(int, input().rstrip().split()))\n(m, n) = (mn[0], mn[1])\narea_full = m * n\narea_domino = 2 * 1\nfactor = area_full // area_domino\nprint(factor)\n","try:\n\t(m, n) = map(int, input().split())\n\tk = m * n\n\tprint(int(k // 2))\nexcept:\n\tpass\n","inputs = list(map(int, input().split()))\ncount = 0\ncount += inputs[0] // 2\ncount *= inputs[1]\nif inputs[0] % 2 == 1:\n\tcount += inputs[1] // 2\nprint(count)\n","(l, b) = map(int, input().split())\ns = l * b / 2\nprint(int(s))\n","(a, b) = map(int, input().split())\nif a == 1 or b == 1:\n\tprint(max(a, b) // 2)\nelse:\n\tprint(a * b // 2)\n","(m, n) = map(int, input().split())\ns = m * n\ncard = 2 * 1\ntotal = s // card\nprint(total)\n","(w, y) = input().split()\n(w, y) = [int(w), int(y)]\na = w * y\nprint(a // 2)\n","(m, n) = map(int, input().split())\narea = m * n\na = 2\ndomino = area // a\nprint(domino)\n","(a, b) = map(int, input().split())\nprint(a * b // 2, end='')\n","line = input()\n(m, n) = [int(i) for i in line.split()]\nif m < n:\n\tt = m\n\tm = n\n\tn = t\nif m % 2 == 0:\n\ta = m // 2\n\ttotal = a * n\nelse:\n\ta = m // 2\n\tb = n // 2\n\ttotal = a * n + b\nprint(total)\n","import math\nelem = input().split(' ')\narea = int(elem[0]) * int(elem[1])\nprint(math.floor(area / 2))\n","t = [int(e) for e in input().split()]\nc = t[0] * t[1]\nprint(c // 2)\n","inp = input(str())\nnum = inp.split(' ')\nm = int(num[0])\nn = int(num[1])\nno = m * n\nposs = 0\nif no % 2 == 0:\n\tposs = no / 2\nelse:\n\tno -= 1\n\tposs = no / 2\nprint(int(poss))\n","import math as ma\n(l, b) = map(int, input().split())\narea = l * b\nprint(ma.floor(area / 2))\n","import math\n(x, y) = [int(i) for i in input().split()]\nanswer = 0\nif x < 2:\n\tanswer = y / 2\nelif y < 2:\n\tanswer = x / 2\nelse:\n\tanswer = x * y / 2\nprint(math.floor(answer))\n","data = [int(i) for i in input().split()]\nprint(max(data[0] // 2 * data[1] + (data[1] // 2 if data[0] % 2 == 1 else 0), data[1] // 2 * data[0] + (data[0] // 2 if data[1] % 2 == 1 else 0)))\n","(m, n) = map(int, input().split())\nds = abs(m * n / 2)\nprint(int(ds))\n","def compute(w, h):\n\tif h == 1:\n\t\treturn w // 2\n\tif w == 1:\n\t\treturn h // 2\n\treturn h * (w // 2) + h // 2 * (w % 2)\n(m, n) = [int(x) for x in input().split()]\nprint(compute(m, n))\n","(n, h) = input().split(' ')\nn = int(n)\nh = int(h)\nnum = h * n // 2\nprint(num)\n","(m, n) = map(int, input().split())\nmul = m * n\nans = mul / 2\nans = int(ans)\nprint(ans)\n","s = input('')\n(a, b) = s.split(' ', 1)\nc = int(a)\nd = int(b)\nif c * d % 2 == 0:\n\tprint(int(c * d / 2))\nelse:\n\te = c * d\n\tf = e - 1\n\tprint(int(f / 2))\n","import math\n(m, n) = map(int, input().split())\npl = m * n\ncl = pl / 2\nprint(int(cl))\n","def solve(m, n):\n\tif m % 2 == 0:\n\t\treturn int(m // 2 * n)\n\telif n % 2 == 0:\n\t\treturn int(n // 2 * m)\n\telse:\n\t\treturn int((m - 1) // 2 * (n - 1) + (m - 1) // 2 + (n - 1) // 2)\n(m, n) = [int(i) for i in input().split(' ')]\nprint(solve(m, n))\n","(w, h) = [int(i) for i in input().split()]\ns = 0\ni = 0\nwhile i < w:\n\tfor t in range(h):\n\t\tif w - i >= 2:\n\t\t\ts += 1\n\ti += 2\nif i != w:\n\tt = 0\n\twhile t + 2 <= h:\n\t\ts += 1\n\t\tt += 2\nprint(s)\n","l = input()\nl = [int(x) for x in l.split()]\nans = l[0] * l[1] // 2\nprint(ans)\n","key_input = input().split(' ')\nn = int(key_input[0])\nm = int(key_input[1])\nprint(int(n * m / 2))\n","(b, h) = map(int, input().split())\nprint(b * h // 2)\n","class Domino:\n\n\tdef solve(self, n, m):\n\t\tresult = 0\n\t\tif n * m % 2 == 0:\n\t\t\tresult = n * m / 2\n\t\telse:\n\t\t\tresult = (n * m - 1) / 2\n\t\treturn int(result)\n(m, n) = map(int, input().split(' '))\ndo = Domino()\nprint(do.solve(n, m))\n","first = input().split(' ')\ntotal = int(first[0]) * int(first[1])\nprint(total // 2)\n","(m, n) = map(int, input().split())\nnum = m * n\nif num % 2 == 0:\n\tnum1 = num / 2\n\tnum1 = int(num1)\n\tprint(num1)\nelse:\n\tnum2 = (num - 1) / 2\n\tnum2 = int(num2)\n\tprint(num2)\n","(M, N) = list(map(int, input().split()))\nnumber = M * N // 2\nif M % 2 != 0 and N % 2 != 0:\n\tnumber = int(number)\nprint(number)\n","dims = input()\ndims = dims.split()\nM = int(dims[0])\nN = int(dims[1])\nprint(int(M * N / 2))\n","(x, y) = map(int, input().split())\nres = x * y\nprint(int(res / 2))\n","def read_int():\n\treturn int(input().strip())\n\ndef read_ints():\n\treturn list(map(int, input().strip().split(' ')))\n\ndef solve():\n\t(M, N) = read_ints()\n\treturn M * N // 2\nprint(solve())\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\nmn = m * n\nans = int(0)\nif mn % 2 != 0:\n\tans = math.floor(mn / 2)\nelse:\n\tans = mn / 2\nans = int(ans)\nprint(ans)\n","aa = list(map(int, input().split(' ')))\na = aa[0]\nb = aa[1]\ndomino_Area = 2\nsum_Rect = (a * b - 1) / domino_Area if a * b % 2 != 0 else a * b / domino_Area\nprint(int(sum_Rect))\n","(l, b) = list(map(int, input().split()))\nif l >= 1 and b >= l and (b <= 16):\n\tres = l * b // 2\n\tprint(res)\n","def DominoPiling():\n\tdimensions = input('').split(' ')\n\tarea = 1\n\tfor i in dimensions:\n\t\tarea *= int(i)\n\tprint(int(area // 2))\nDominoPiling()\n","import math, string, itertools, fractions, heapq, collections, re, array, bisect\nfrom itertools import chain, dropwhile, permutations, combinations\nfrom collections import defaultdict\n\ndef main(m, n):\n\tans = m * n // 2\n\tprint(ans)\n\ndef main_input(info=0):\n\t(m, n) = map(int, input().split())\n\tmain(m, n)\nmain_input()\n","(num_1, num_2) = [int(i) for i in input().split()]\nnum_squares = num_1 * num_2\nif num_squares % 2 == 0:\n\tprint(num_squares // 2)\nelse:\n\tprint((num_squares - 1) // 2)\n","import math\n(a, b) = [int(x) for x in input().split()]\nn = 2\ns = a * b / 2\nres = math.floor(s)\nprint(res)\n","import math\n(m, n) = (int(x) for x in input().split())\nprint(math.floor(m * n * 0.5))\n","eersteInput = input()\neersteInputSplitted = eersteInput.split()\nm = int(eersteInputSplitted[0])\nn = int(eersteInputSplitted[1])\noppervlak = m * n\naantal = int(oppervlak / 2)\nprint(aantal)\n","(height, weight) = input().split(' ')\nheight = int(height)\nweight = int(weight)\ns = height * weight\nx = s % 2\nanswer = (s - x) / 2\nanswer = int(answer)\nprint(answer)\n","x = input().split()\nm = int(x[0])\nn = int(x[1])\nj = int(x[0]) * int(x[1]) // 2\nprint(j)\n","x = list(map(int, input().split()))\nif x[0] >= 1 and x[0] <= 16 and (x[1] >= 1) and (x[1] <= 16):\n\tr = x[0] * x[1]\n\tprint(int(r / 2))\n","(x, y) = map(int, input().split(' '))\nres = x // 2 * y\nif x % 2 != 0:\n\tres += y // 2\nprint(res)\n","(m, n) = input().split()\ndom = int(int(m) * int(n) / 2)\nprint(dom)\n","f = [int(i) for i in input().split(' ')]\nr = f[0] * f[1] // 2\nprint(r)\n","size = input().split()\nm = int(size[0])\nn = int(size[1])\nif m * n % 2 == 0:\n\tprint(int(m * n / 2))\nelif m * n % 2 != 0:\n\te = m * n - 1\n\tprint(int(e / 2))\n","import math\n(m, n) = [int(x) for x in input().split()]\nif 16 >= n and n >= m and (m >= 1):\n\tprint(math.floor(n * m / 2))\n","s = input().split()\nprint(eval(s[0]) * eval(s[1]) // 2)\n","(m, n) = map(int, input().split())\nk = 0\nfor i in range(m * n, 1, -2):\n\tk += 1\nprint(k)\n","num = input().split()\nn1 = int(num[0])\nn2 = int(num[1])\ncheck = n2 >= n1\nif check:\n\tres = n1 * n2\n\tprint(res // 2)\n","(m, n) = [int(x) for x in input().split()]\nimport math\na = m * n / 2\nb = math.floor(a)\nprint(b)\n","(m, n) = map(int, input().split())\nif m >= 1 and n >= 1 and (m * n % 2 == 0):\n\tx = m * n / 2\n\tx = int(x)\n\tprint(x)\nelse:\n\ty = (m * n - 1) / 2\n\ty = int(y)\n\tprint(y)\n","(m, n) = list(map(int, input().split()))\nif m % 2 == 0:\n\tsm = m // 2 * n\nelif m == 1:\n\tsm = n // 2\nelse:\n\tsm = m // 2 * n + n // 2\nprint(sm)\n","(M, N) = map(int, input().split())\na = M * N\nk = 0\nif a % 2 != 0:\n\twhile a != 1:\n\t\ta -= 2\n\t\tk += 1\nelse:\n\twhile a != 0:\n\t\ta -= 2\n\t\tk += 1\nprint(k)\n","S = input()\n(m, n) = map(int, S.split())\nsum = int(m / 2) * n\nif m % 2 == 1:\n\tsum += n / 2\nprint(int(sum))\n","dat = input().split()\na = int(dat[0])\nb = int(dat[1])\nif a % 2 == 1:\n\tif b % 2 == 1:\n\t\tc = (a - 1) / 2\n\t\td = (b - 1) / 2\n\t\tn = 2 * c * d + c + d\n\telse:\n\t\tn = a * b / 2\nelse:\n\tn = a * b / 2\nprint(int(n))\n","(x, y) = input().split()\nx = int(x)\ny = int(y)\ni = 2\nz = 0\nm = 1\nk = 0\nif y >= 2 and x >= y:\n\twhile i <= y:\n\t\tz += 1\n\t\ti += 2\n\ti = 2\n\tif y % 2 == 1:\n\t\twhile i <= x:\n\t\t\tk += 1\n\t\t\ti += 2\n\tprint(x * z + k)\nelif x >= 2 and x < y:\n\twhile i <= x:\n\t\tz += 1\n\t\ti += 2\n\ti = 2\n\tif x % 2 == 1:\n\t\twhile i <= y:\n\t\t\tk += 1\n\t\t\ti += 2\n\tprint(y * z + k)\nelif x == 1 or y == 1:\n\tif x == 1 and y >= 2:\n\t\twhile y >= i:\n\t\t\tz += 1\n\t\t\ti += 2\n\tif y == 1 and x >= 2:\n\t\twhile x >= i:\n\t\t\tz += 1\n\t\t\ti += 2\n\tprint(z)\n","def max_no_domino(m, n):\n\treturn m * n // 2\n(m, n) = [int(x) for x in input().split()]\nprint(max_no_domino(m, n))\n","cin = input().split(' ')\n(m, n) = (int(cin[0]), int(cin[1]))\nif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelif m == 1 and n == 1:\n\tprint(0)\nelif m == 1:\n\tprint(int(n / 2))\nelif n == 1:\n\tprint(int(m / 2))\nelse:\n\tprint(int(m / 2) * n + int(n / 2))\n","(m, n) = [int(i) for i in input().split()]\nif m % 2 == 1 and n % 2 == 1:\n\tprint((m * n - 1) // 2)\nelse:\n\tprint(m * n // 2)\n","def domino(l, w):\n\tarea = int(l * w)\n\tpiece = int(2)\n\treturn int(area / piece)\n(m, n) = map(int, input().split())\nprint(domino(m, n))\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\nx = m * n\na = math.floor(x / 2)\nprint(a)\n","inp = input().split()\ninp = [int(i) for i in inp]\nm = inp[0]\nn = inp[1]\ntotal = m * n\nif total % 2 == 0:\n\tfinal = total // 2\nelse:\n\tfinal = (total - 1) // 2\nprint(final)\n","def domino(m, n):\n\tboard = m * n\n\tprint(board // 2)\n(m, n) = map(int, input().split())\ndomino(m, n)\n","import sys\n\ndef solution():\n\tline = input()\n\tm = int(line.split(' ')[0])\n\tn = int(line.split(' ')[1])\n\tresult = 0\n\tif m < 2 and n < 2:\n\t\tprint(result)\n\t\treturn\n\tif m < 2:\n\t\tresult = int(n / 2)\n\t\tprint(result)\n\t\treturn\n\tif n < 2:\n\t\tresult = int(m / 2)\n\t\tprint(result)\n\t\treturn\n\tresult = n * int(m / 2)\n\tif m % 2 != 0:\n\t\tresult += int(n / 2)\n\tprint(result)\nsolution()\n","arr = list(map(int, input().split()))\nm = arr[0]\nn = arr[1]\nrect_area = m * n\nstand_area = 2\ndominos = int(rect_area / stand_area)\nprint(dominos)\n","import math\n(n, m) = input().split(' ')\nn1 = int(n)\nm1 = int(m)\nprint(math.floor(n1 * m1 / 2))\n","def solve():\n\tarr = list(map(int, input().split()))\n\tm = arr[0]\n\tn = arr[1]\n\tprint(m * n // 2)\nsolve()\n","(m, n) = [int(x) for x in input().split()]\nprint([int((m * n - 1) * 0.5), int(m * n * 0.5)][m % 2 == 0 or n % 2 == 0])\n","(m, n) = list(map(int, input().split()))\ns = m // 2 * n\nif m & 1:\n\ts += n // 2\nprint(s)\n","def watermelon():\n\tw = int(input())\n\tif w % 2 == 0:\n\t\tprint('YES')\n\telse:\n\t\tprint('NO')\n\ndef way_too_long_words():\n\tn = int(input())\n\twords = [input() for x in range(n)]\n\tfor word in words:\n\t\tif len(word) > 10:\n\t\t\tprint(f'{word[0]}{len(word) - 2}{word[-1]}')\n\t\telse:\n\t\t\tprint(word)\n\ndef team():\n\tn = int(input())\n\tv = [[int(x) for x in input().split()] for i in range(n)]\n\to = 0\n\tfor l in v:\n\t\tif l.count(1) >= 2:\n\t\t\to += 1\n\tprint(o)\n\ndef next_round():\n\t(n, k) = map(int, input().split())\n\ts = [int(x) for x in input().split()]\n\to = 0\n\ti = s[k - 1]\n\tfor j in s:\n\t\tif j >= i and j != 0:\n\t\t\to += 1\n\tprint(o)\n\ndef domino_piling():\n\timport math\n\t(m, n) = map(int, input().split())\n\to = 0\n\tif m * n < 2:\n\t\tprint(0)\n\t\texit()\n\tif m % 2 == 0:\n\t\to = m * n / 2\n\telif n % 2 == 0:\n\t\to = m * n / 2\n\telse:\n\t\to = math.floor(m * n / 2)\n\tprint(int(o))\ndomino_piling()\n","t = input().split()\n(a, b) = (int(t[0]), int(t[1]))\nprint(a * b // 2)\n","def foo():\n\treturn 1\n\ndef main():\n\tfirst_line = input()\n\tfirst_line = first_line.split()\n\ta = int(first_line[0])\n\tb = int(first_line[1])\n\tprint(int(a * b / 2))\nmain()\n","import math\n(a, b) = input().split()\na = int(a)\nb = int(b)\nif a * b % 2 == 0:\n\tprint(int(a * b / 2))\nelif a * b % 2 == 1:\n\tprint(int((a * b - 1) / 2))\n","x = input()\nb = x.partition(' ')\nprint(int(b[0]) * int(b[2]) // 2)\n","import math\nlineArr = []\n\ndef intInput():\n\tglobal lineArr\n\tlineArr = input().split(' ')\n\tfor i in range(len(lineArr)):\n\t\tlineArr[i] = int(lineArr[i])\nintInput()\nm = lineArr[0]\nn = lineArr[1]\n2\nif n % 2 == 0:\n\td = n / 2 * m\nelif m % 2 == 0:\n\td = m / 2 * n\nelse:\n\td = math.floor(m * n / 2)\nd = int(d)\nprint(d)\n","(m, n) = [int(i) for i in str(input()).split(' ')[:2]]\nif max(m, n) % 2 == 1:\n\tprint(min(m, n) * (max(m, n) // 2) + min(m, n) // 2)\nelse:\n\tprint(min(m, n) * (max(m, n) // 2))\n","a = input().split()\nif int(a[0]) % 2 == 0:\n\tprint(int(int(a[0]) / 2 * int(a[1])))\nelif int(a[1]) % 2 == 0:\n\tprint(int(int(a[1]) / 2 * int(a[0])))\nelse:\n\tprint(int((int(a[1]) * int(a[0]) - 1) / 2))\n","import math\nw = input().split()\ns = int(w[0])\nc = int(w[1])\nprint(s * c // 2)\n","(n, k) = map(int, input().split())\nprint(str(int(n * k / 2)))\n","import math\nline = input()\nls = line.split(' ')\narea = int(ls[0]) * int(ls[1])\nprint(math.floor(area / 2))\n","def solution():\n\t(m, n) = [int(i) for i in input().split()]\n\tif m % 2 == 0 and n % 2 == 0:\n\t\tprint(m * n // 2)\n\telif m % 2 == 0:\n\t\tprint(m * (n // 2) + m // 2)\n\telif n % 2 == 0:\n\t\tprint(n * (m // 2) + n // 2)\n\telse:\n\t\tprint(n // 2 * (m // 2) * 2 + m // 2 + n // 2)\nsolution()\n","(x, y) = input().split()\ni = int(x)\nj = int(y)\nprint(i * j // 2)\n","(x, y) = input().split()\nM = int(x)\nN = int(y)\nb = M * N // 2\nprint(b)\n","from sys import stdin\n\ndef check(mask, i):\n\treturn bool(mask >> i & 1)\n\ndef add(mask, i):\n\tmask |= 1 << i\n\treturn mask\n\ndef remove(mask, i):\n\tmask &= ~(1 << i)\n\treturn mask\n\ndef main():\n\tline = stdin.readline\n\t(n, m) = map(int, line().split())\n\tif not n % 2 or not m % 2:\n\t\tprint(n * m // 2)\n\telse:\n\t\tprint(n // 2 * m + m // 2)\nmain()\n","from sys import stdin\n(lines, line_index) = (stdin.readlines(), -1)\n\ndef get_line():\n\tglobal lines, line_index\n\tline_index += 1\n\treturn lines[line_index]\n\ndef solve(m, n):\n\ta1 = m // 2 * n + m % 2 * n // 2\n\ta2 = n // 2 * m + n % 2 * m // 2\n\treturn max(a1, a2)\n\ndef main():\n\t(m, n) = [int(x) for x in get_line().split()]\n\tprint(solve(m, n))\nmain()\n","y = input()\nt = y.split(' ')\ng = []\nfor i in t:\n\tg.append(int(i))\nd = g[0] * g[1]\nprint(d // 2)\n","import math\n(a, b) = map(int, input().split())\nd = math.floor(a * b / 2)\nprint(d)\n","import sys\n(n, m) = map(int, sys.stdin.readline().split())\narea = n * m\nprint(int(area / 2))\n","(m, n) = input().split()\nprint('%i' % (int(m) * int(n) // 2))\n","import sys\n(m, n) = map(int, input().split())\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\nk = m * n\nf = k // 2\nprint(f)\n","a = input()\na = a.split()\nc = int(a[0]) * int(a[1])\nc = c // 2\nprint(c)\n","f = input().split()\n(a, b) = [int(f[i]) for i in (0, 1)]\nprint(str(a * b // 2))\n","size = [int(i) for i in input().split()]\nif size[0] * size[1] % 2 == 0:\n\tprint(int(size[0] * size[1] / 2))\nelse:\n\tprint(int((size[0] * size[1] - 1) / 2))\n","(M, N) = [int(x) for x in input().split()]\nnum = M * N\nresult = num // 2\nprint(result)\n","board = input().split(' ')\nresult = int(board[0]) * int(board[1]) // 2\nprint(result)\n","import math\nfrom sys import stdin, stdout\nnumbers = [int(x) for x in stdin.read().split()]\ny = numbers.pop(0)\nz = numbers.pop(0)\ndimensions = y * z\nprint(math.floor(dimensions / 2))\n","import math\ns = list(map(int, input().split(' ')))\np = s[0]\nq = s[1]\nprint(math.floor(p * q / 2))\n","(M, N) = map(int, input().split())\na = M * N\ni = 1\nwhile i > 0:\n\tans = 2 * i\n\tif ans > a:\n\t\tbreak\n\ti += 1\nprint(i - 1)\n","(m, n) = list(map(int, input().split()))\nans = 0\nans = int(ans + m * n / 2)\nprint(ans)\n","(m, n) = map(int, input().split())\ns = m // 2 * n\nif m % 2:\n\ts += n // 2\nprint(s)\n","def solve(m, n):\n\tg = m if m > n else n\n\tl = m if m < n else n\n\treturn g * (l // 2) + g // 2 * (l % 2)\n(m, n) = map(int, input().strip().split(' '))\nprint(solve(m, n))\n","in1 = input().split()\na = int(in1[0])\nb = int(in1[1])\np = a * b\nif p % 2 == 0:\n\tprint(p // 2)\nelse:\n\tprint((p - 1) // 2)\n","import sys\nfor line in sys.stdin:\n\tparas = str(line).strip().split()\n\tm = int(paras[0])\n\tn = int(paras[1])\n\tprint(int(m * n / 2))\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\ttile = int(m / 2 * n)\nelif n % 2 == 0:\n\ttile = int(n / 2 * m)\nelse:\n\tm1 = m // 2\n\ttemp = m1 * n\n\tif m - m1 * 2 != 0:\n\t\ttile = temp + n // 2\n\telse:\n\t\ttile = temp\nprint(tile)\n","(n, m) = map(int, input().split())\na = n * m\nif a % 2 == 0:\n\ts = a / 2\nelse:\n\ts = a // 2\nprint('{0:.0f}'.format(s))\n","board = list(map(int, input().split(' ')))\nsquares = board[0] * board[1]\nprint(int(squares / 2))\n","size = input()\nlistsize = size.split()\nm = int(listsize[0])\nn = int(listsize[1])\nif m >= 1 and m <= n and (n <= 16):\n\tarea = m * n\n\tif area % 2 != 0:\n\t\tarea -= 1\n\tprint(int(area / 2))\n","S = [int(x) for x in input().split()]\nN = S[1] * (S[0] // 2) + S[1] * (S[0] % 2) // 2\nprint(N)\n","(width, height) = map(int, input().split())\nif width * height % 2 == 1:\n\tprint(int((width * height - 1) / 2))\nelse:\n\tprint(int(width * height / 2))\n","(M, N) = [int(x) for x in input().split()]\ny = M * N // 2\nprint(y)\n","(x, y) = map(int, input().split())\nr_x = x // 2 * y\nr_y = x % 2 * y // 2\nprint(r_x + r_y)\n","(a, b) = map(int, input().split())\narea = a * b\ndomino = area // 2\nprint(domino)\n","(n, m) = map(int, input().split())\nh = m * n\nd = 0\nwhile h > 1:\n\th -= 2\n\td += 1\nprint(d)\n","A = input()\narr = list(map(int, A.split(' ')))\na = arr[0]\nb = arr[1]\nc = a % 2\nprint(int(a / 2) * b + c * int(b / 2))\n","class Scanner:\n\n\tdef __init__(self):\n\t\tself.current_tokens = []\n\n\tdef remaining_tokens(self):\n\t\treturn len(self.current_tokens)\n\n\tdef nextline(self):\n\t\tassert self.remaining_tokens() == 0, 'Reading next line with remaining tokens'\n\t\treturn input()\n\n\tdef nexttokens(self):\n\t\treturn self.nextline().split()\n\n\tdef nexttoken(self):\n\t\tif len(self.current_tokens) == 0:\n\t\t\tself.current_tokens = self.nexttokens()\n\t\treturn self.current_tokens.pop(0)\n\n\tdef nextints(self):\n\t\treturn list(map(int, self.nexttokens()))\n\n\tdef nextint(self, n=1):\n\t\treturn (int(self.nexttoken()) for i in range(n))\nstdin = Scanner()\nnextint = stdin.nextint\nnextints = stdin.nextints\nnextline = stdin.nextline\n(m, n) = nextint(2)\np = m * n\nprint(p // 2)\n","data = input().split()\nn = int(data[0])\nm = int(data[1])\nf = int(n * m / 4)\nk = n * m - f * 4\nf *= 2\nif k >= 2:\n\tf += 1\nprint(f)\n","import sys\nfrom collections import Counter as C\n(m, n) = map(int, input().split())\nif not m & 1 or not n & 1:\n\tif not m & 1:\n\t\tprint(m // 2 * n)\n\telif not n & 1:\n\t\tprint(n // 2 * m)\nelse:\n\tprint(m // 2 * n + n // 2)\n","(m, n) = input().split(' ')\npiece = 0\ni = 1\nwhile i <= int(n):\n\tpiece += int(m) // 2\n\ti += 1\nif int(m) % 2 != 0:\n\tpiece += int(n) // 2\nprint(piece)\n","num1 = input().split(' ')\nprint(int(int(num1[0]) * int(num1[1]) / 2))\n","def domino_piling(board_size_data):\n\tboard_size_list = board_size_data.split(' ')\n\tnum_rows = int(board_size_list[0])\n\tnum_cols = int(board_size_list[1])\n\tboard_area = num_rows * num_cols\n\treturn board_area // 2\nboard_size_str = input()\nnum_dominioes = domino_piling(board_size_str)\nprint(num_dominioes)\n","def maximum_number(n, m):\n\tif n % 2 == 0 or m % 2 == 0:\n\t\treturn int(n * m / 2)\n\treturn int((n - 1) * m / 2 + m // 2)\n\ndef main():\n\t(n, m) = tuple(map(int, input().split(' ')))\n\tresult = maximum_number(n, m)\n\tprint(result)\nmain()\n","theInputString = input()\ntheInputString = str.split(theInputString, ' ')\n\ndef getMaximumPlacement(x, y):\n\tif x <= 1 and y <= 1:\n\t\treturn 0\n\tif x >= y:\n\t\treturn x // 2 * y + getMaximumPlacement(x % 2, y)\n\telif y > x:\n\t\treturn y // 2 * x + getMaximumPlacement(x, y % 2)\ncounter = getMaximumPlacement(int(theInputString[0]), int(theInputString[1]))\nprint(counter)\n","(m, n) = map(int, input().split())\nadjusted_m = m\nif m % 2 != 0:\n\tadjusted_m = m - 1\nadjusted_n = n\nif n % 2 != 0:\n\tadjusted_n = n - 1\nnum = adjusted_m * adjusted_n // 2\nif adjusted_m != m:\n\tnum += adjusted_n // 2\nif adjusted_n != n:\n\tnum += adjusted_m // 2\nprint(num)\n","raw_input = input().split(' ')\nm = int(raw_input[0])\nn = int(raw_input[1])\ni = 1\nnum = 0\nwhile 2 * i <= m * n:\n\tif m * n > 1 and m * n <= 256:\n\t\tnum = i\n\t\ti = i + 1\n\telse:\n\t\tnum = 0\nprint(num)\n","def main():\n\t(m, n) = getInputs()\n\tif m % 2 == 0:\n\t\ttotal = m // 2 * n\n\telif n % 2 == 0:\n\t\ttotal = m * (n // 2)\n\telif m > 2:\n\t\ttotal = m // 2 * n + n // 2\n\telif n > 2:\n\t\ttotal = m * (n // 2) + m // 2\n\telse:\n\t\ttotal = 0\n\tprint(round(total))\n\ndef getInputs():\n\t(m, n) = input().split()\n\treturn (int(m), int(n))\nmain()\n","(rows, column) = [int(i) for i in input().split()]\nif rows % 2 == 0 and column % 2 == 0:\n\tprint(column * (rows // 2))\nelif rows % 2 != 0 and column % 2 != 0:\n\tif rows > column:\n\t\tprint(column * (rows // 2) + column // 2)\n\telse:\n\t\tprint(rows * (column // 2) + rows // 2)\nelse:\n\teven = rows\n\todd = column\n\tif rows % 2 != 0:\n\t\t(even, odd) = (odd, even)\n\tprint(odd * (even // 2))\n","def solve(m, n):\n\tboardarea = m * n\n\tdom_area = 2 * 1\n\treturn boardarea // dom_area\n(m, n) = map(int, input().split(' '))\nprint(solve(m, n))\n","t = input()\n(m, n) = [int(x) for x in t.split()]\nres = m * n\nd = res // 2\nprint(d)\n","(N, M) = input(' ').split()\nN = int(N)\nM = int(M)\nnumber_of_dominos = M * N // 2\nprint(number_of_dominos)\n","s = input()\n(mm, nn) = s.split(' ')\nm = int(mm)\nn = int(nn)\na = m * n // 2\nprint(a)\n","import math\ninp = input()\nM = int(inp[0:2])\nN = int(inp[2:5])\nNN = 0\ngap = 0\nif M == 1 and N == 1:\n\tprint(0)\nelse:\n\tif N / 2 == math.floor(N / 2):\n\t\tNN = N\n\telse:\n\t\tNN = N - 1\n\t\tif M / 2 == math.floor(M / 2):\n\t\t\tgap = M\n\t\telse:\n\t\t\tgap = M - 1\n\tprint(int(M * (NN / 2) + gap / 2))\n","line = input().split()\nn = int(line[0])\nm = int(line[1])\npiece = int(m / 2) * n\nif m % 2:\n\tpiece += int(n / 2)\nprint(piece)\n","(a, y) = input().split()\na = int(a)\ny = int(y)\nc = a * y\nprint(c // 2)\n","(m, n) = list(map(int, input().split()))\nout_value = m * n / 2\nprint(int(out_value))\n","class Solution:\n\n\tdef solve(self, m, n):\n\t\treturn m * n // 2\nsol = Solution()\n[m, n] = list(map(int, input().strip().split()))\nprint(sol.solve(m, n))\n","(k, n) = input().split()\nk = int(k)\nn = int(n)\nc = k * n\nf = c // 2\nprint(f)\n","dim = [int(i) for i in input().split(' ')]\nboard = dim[0] * dim[1]\nans = board // 2\nprint(ans)\n","line1 = input()\nline = line1.split(' ', 2)\ndimension = int(line[0]) * int(line[1])\nif dimension % 2 == 0:\n\tprint(int(dimension / 2))\nelse:\n\tprint(int((dimension - 1) / 2))\n","q = input()\nw = q.split(' ')\ne = []\nfor i in w:\n\te.append(int(i))\nr = e[0] * e[1]\nprint(r // 2)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nt = m * int(n / 2)\nif n % 2 != 0:\n\tt = t + int(m / 2)\nprint(t)\n","import math\n(a, b) = map(int, input().split())\nx = math.floor(a * b / 2)\nprint(x)\n","nm = list(map(int, input().split()))\nif nm[0] * nm[1] % 2 > 0:\n\ttotal = int(nm[0] * nm[1] / 2 - 0.5)\nelse:\n\ttotal = int(nm[0] * nm[1] / 2)\nprint(total)\n","(m, n) = map(int, input().split())\ndom = 2\nboard = m * n\nresult = int(board / dom)\nprint(result)\n","(m, n) = list(map(int, input().strip().split(' ')))\nans = m * (n // 2)\nif n % 2 == 0:\n\tprint(ans)\nelse:\n\tans += m // 2\n\tprint(ans)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nL = m * n // 2\nprint(L)\n","(n, m) = map(int, input().split())\nc = m * n\nli = []\nif c % 2 == 1:\n\tli.append((c - 1) // 2)\nelse:\n\tli.append(c // 2)\nprint(li[0])\n","(m, n) = [int(i) for i in input().split()]\nb = m * n // 2\nprint(b)\n","input_text = input()\nnm = input_text.split(' ')\n(n, m) = (int(nm[0]), int(nm[1]))\nnumber = int(n * m * 0.5)\nprint(number)\n","(p, l) = map(int, input().split())\nprint(int(p * l / 2))\n","(n, k) = input().split()\nn = int(n)\nk = int(k)\nnum = 0\nif n % 2 == 0 or k % 2 == 0:\n\tnum = int(n * k / 2)\nelse:\n\tnum = int((n * k - 1) / 2)\nprint(num)\n","(M, N) = map(int, input().split())\nm = M // 2\nif M % 2 == 0:\n\tprint(m * N)\nelse:\n\tprint(m * N + N // 2)\n","mn = [int(n) for n in input().split()]\nm = mn[0]\nn = mn[1]\nimport math\nnum = n * math.floor(m / 2)\nif m % 2 == 1:\n\tnum += math.floor(n / 2)\nprint(num)\n","l = list(map(int, input().split()))\na = l[0] * l[1]\nn = a // 2\nprint(n)\n","m_n = input().split()\nsurface = int(m_n[0]) * int(m_n[1])\nprint(surface // 2)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\na1 = 0\nwhile b > 0:\n\tif a % 2 != 0 and b >= 2:\n\t\ta1 += a\n\t\tb -= 2\n\telif a % 2 == 0:\n\t\ta1 += a // 2\n\t\tb -= 1\n\telse:\n\t\ta1 += a // 2\n\t\tb = 0\nprint(a1)\n","(m, n) = map(int, input().split())\nnum = m // 2 * n\nif m % 2 != 0:\n\tnum += n // 2\nprint(num)\n","(m, n) = input().split()\nmn = int(m) * int(n)\nif mn % 2 == 0 and mn >= 2:\n\tans = mn / 2\nelse:\n\tmn -= 1\n\tans = mn / 2\nprint(round(ans))\n","import math\nl = input().split(' ')\n(M, N) = (int(l[0]), int(l[1]))\nprint(int(M * N / 2))\n","(width, height) = input().split()\nwidth = int(width)\nheight = int(height)\nprint(int(width * height / 2))\n","(m, n) = map(int, input().split())\ndom = 2 * 1\nboard = m * n\nprint(board // dom)\n","mystr = input()\nmystrL = mystr.split()\nn = int(mystrL[1])\nm = int(mystrL[0])\nif n % 2 == 0:\n\tprint(int(n / 2 * m))\nelif n % 2 != 0:\n\tprint(int(n // 2 * m + m // 2))\n","(m, n) = map(int, input().strip().split())\nr = m * n\nfor i in range(m * n):\n\tif i * 2 > r:\n\t\tprint(i - 1)\n\t\texit()\n\telif r == 1:\n\t\tprint(0)\n\t\texit()\n\telif r == 2:\n\t\tprint(1)\n\t\texit()\n","(n, m) = [int(i) for i in input().split(' ')]\nsol = int(m / 2) * n + m % 2 * int(n / 2)\nprint(sol)\n","(M, N) = map(int, input().split(' '))\nif 1 <= M <= N <= 16:\n\ts = M * N\n\tprint(s // 2)\n","import sys\nstring = input()\ns = string.split(' ')\nm = s[0]\nn = s[1]\nx = int(int(m) * int(n))\nx = int(x / 2)\nprint(x)\n","(x, y) = map(int, input().split())\nans = x * y // 2\nprint(ans)\n","import sys\nrawdata = sys.stdin.read()\ndata = list((int(n) for n in rawdata.split()))\nboardSize = data[0] * data[1]\nprint(int(boardSize / 2))\n","arr = list(map(int, input().rstrip().split()))\nans = arr[0] * arr[1] // 2\nprint(ans)\n","(m, n) = list(map(int, input().split()))\nS = 2\nK = m * n // S\nprint(K)\n","import sys\n\ndef get_vals(func=str):\n\treturn map(func, input().split())\n\ndef get(func=str):\n\treturn func(input())\ninput = lambda : sys.stdin.readline().rstrip('\\r\\n')\nwrite = sys.stdout.write\n\ndef test():\n\tpass\n\ndef main():\n\t(n, m) = get_vals(int)\n\tprint(n * m // 2)\nmain()\n","coordinates = [int(i) for i in input().split()]\ntotal_squares = coordinates[0] * coordinates[1]\nprint(total_squares // 2)\n","import math as m\nnum = input()\nnum = num.split()\nl = int(num[0])\nw = int(num[-1])\nprint(m.floor(l * w / 2))\n","def get_domino_amount(board):\n\tdomino_amount = 0\n\tfor i in range(len(board)):\n\t\tfor k in range(len(board[i])):\n\t\t\tcurrent_item = board[i][k]\n\t\t\tif len(current_item) == 0:\n\t\t\t\tif k < len(board[i]) - 1:\n\t\t\t\t\tnext_item = board[i][k + 1]\n\t\t\t\t\tif len(next_item) == 0:\n\t\t\t\t\t\tdomino_amount += 1\n\t\t\t\t\t\tcurrent_item.append('-')\n\t\t\t\t\t\tnext_item.append('-')\n\t\t\t\telif k == len(board[i]) - 1 and i < len(board) - 1:\n\t\t\t\t\tbelow_item = board[i + 1][k]\n\t\t\t\t\tif len(below_item) == 0:\n\t\t\t\t\t\tdomino_amount += 1\n\t\t\t\t\t\tcurrent_item.append('|')\n\t\t\t\t\t\tbelow_item.append('|')\n\treturn domino_amount\n\ndef main():\n\t(m, n) = [int(i) for i in input().split()]\n\tboard = [[[] for k in range(m)] for i in range(n)]\n\tamount = get_domino_amount(board)\n\tprint(amount)\nmain()\n","import math\n(w, h) = [int(x) for x in input().split()]\ndominos = math.floor(w / 2) * h\nif w % 2 == 1:\n\tdominos += math.floor(h / 2)\nprint(dominos)\n","import re\ns = input()\npl = re.split(' ', s)\npl = [int(item) for item in pl]\ns = pl[0] * pl[1]\nprint(int(s / 2))\n","s = [int(i) for i in input().split()]\nans = int(s[0] * s[1] / 2)\nprint(ans)\n","(M, N) = map(int, input().split())\nareaOfBoard = M * N\nnumOfPieces = int(areaOfBoard / 2)\nprint(numOfPieces)\n","size = input().split()\na = int(size[0])\nb = int(size[1])\nprint(a * b // 2)\n","import math\nn = input().split(' ')\n(f, s) = (int(n[0]), int(n[1]))\nprint(math.floor(f * s / 2))\n","(M, N) = map(int, input().split())\np = M * N\ns = int(p / 2)\nprint(s)\n","import math\na = [int(x) for x in input().split()]\nm = a[0]\nn = a[1]\nif m % 2 == 0:\n\tprint(int(m / 2 * n))\nelif n % 2 == 0:\n\tprint(int(n / 2 * m))\nelse:\n\tprint(min(m, n) * math.floor(max(m, n) / 2) + math.floor(min(m, n) / 2))\n","lst = input().split()\narea = int(lst[0]) * int(lst[1])\nprint(area // 2)\n","x = input().split()\nfor i in x:\n\tn = int(x[0])\n\tm = int(x[1])\nL = n * m\nmaks = L // 2\nprint(maks)\n","(M, N) = list(map(int, input().strip().split()))\nres = M * N // 2\nprint(res)\n","(M, N) = tuple(map(int, input().split()))\nlied = N // 2 * M + N % 2 * M // 2\nstand = M // 2 * N + M % 2 * N // 2\nprint(max(lied, stand))\n","(M, N) = input().split()\ndomino_count = 0\nfor n in range(0, int(N)):\n\tdomino_count += int(M) // 2\nif int(M) % 2 == 1:\n\tdomino_count += int(N) // 2\nprint(domino_count)\n","(n, m) = list(map(int, input().split()))\ndominos = 0\ndominos += n * (m // 2)\nif m % 2 != 0:\n\tdominos += n // 2\nprint(dominos)\n","grid = input('')\nh = int(grid.split()[0])\nw = int(grid.split()[1])\nprint(str(h * w // 2))\n","import math\n(m, n) = map(int, input().split())\nnumber = math.floor(m * n / 2)\nprint(number)\n","import math\nstr = input().split()\nM = int(str[0])\nN = int(str[1])\nprint(N * M // 2)\n","import sys\nfor line in sys.stdin:\n\tline = line.rstrip()\n\tline = line.split()\n\tline = list(map(int, line))\n\tprint(int(line[0] * line[1] / 2))\n","board = input('')\nboard = board.split(' ')\narea = int(board[0]) * int(board[1])\nans = area // 2\nprint(ans)\n","(a, b) = input().split()\nwow = int(a) * int(b) // 2\nprint(wow)\n","(m, n) = map(int, input().split())\nif m // 2 >= n // 2:\n\tw = n // 2 * m\n\tw = (n * m - w * 2) // 2 + w\nelse:\n\tw = m // 2 * n\n\tw = (n * m - w * 2) // 2 + w\nprint(w)\n","(m, n) = map(int, input().split())\ns = (n - n % 2) * (m - m % 2) // 2\nif n % 2 == 1:\n\tif m % 2 == 1:\n\t\ts += m // 2 + n // 2\n\telse:\n\t\ts += m // 2\nelif m % 2 == 1:\n\ts += n // 2\nprint(s)\n","import math\nx = input()\nx = x.split()\na = int(x[0])\nb = int(x[1])\nres = a * b / 2\nprint(math.floor(res))\n","import sys\ninput = sys.stdin.buffer.readline\n\ndef solution():\n\t(n, m) = map(int, input().split())\n\tprint(m * n // 2)\nt = 1\nfor _ in range(t):\n\tsolution()\n","board = input().split(' ')\nM = int(board[0])\nN = int(board[1])\nboard_size = M * N\ndomino = 2\nprint(int(board_size / domino))\n","l = list(input().split())\nm = int(l[0])\nn = int(l[1])\nboard = []\nl1 = []\nif m >= 1 and m <= n and (n <= 16):\n\tfor i in range(n):\n\t\tfor j in range(m):\n\t\t\tl1.append(0)\n\t\tboard.append(l1)\n\t\tl1 = []\n\tsum = 0\n\tk = 0\n\tfor i in range(len(board)):\n\t\tsum += len(board[i]) // 2\n\t\tk = 0\n\t\tfor j in range(0, len(board[i]) // 2):\n\t\t\tboard[i][k] = 1\n\t\t\tboard[i][k + 1] = 1\n\t\t\tk += 2\n\tfor i in range(0, len(board), 2):\n\t\tif i == len(board) - 1:\n\t\t\tbreak\n\t\telif board[i][len(board[i]) - 1] == 0 and board[i + 1][len(board[i]) - 1] == 0:\n\t\t\tsum += 1\nprint(sum)\n","l = list(map(int, input().split()))\nimport math\nprint(math.trunc(l[0] * l[1] / 2))\n","count = 0\nthe_string = input()\n(x, y) = the_string.split()\nx = int(x)\ny = int(y)\nif x >= 2:\n\tcount = y\nz = int(x / 2)\nif z > 1:\n\tcount = int(x / 2) * y\nif x % 2 != 0:\n\tcount += int(y / 2)\nprint(int(count))\n","(m, n) = map(int, input().split())\nr = m * n\ncount = 0\ni = 0\na_o_s = 2\nwhile True:\n\ti += 1\n\ta_o_s = 2 * i\n\tif a_o_s > r:\n\t\tbreak\nprint(i - 1)\n","stroka = input().split()\nm = int(stroka[0])\nn = int(stroka[1])\nk = 0\nif n % 2 != 0:\n\tk = 1\nprint(str(int((n - k) / 2 * m + int(k * m / 2))))\n","def can_fit(m, n, x=0, y=0):\n\tmove = 0\n\tif x + 2 <= m:\n\t\tmove += can_fit(m, n, x + 2, y) + 1\n\telif y + 1 < n:\n\t\tmove += can_fit(m, n, 0, y + 1)\n\treturn move\n\ndef domino_piling():\n\tx = input()\n\t(inp1, inp2) = x.split(' ')\n\tm = int(inp1)\n\tn = int(inp2)\n\tmove = can_fit(int(m), int(n))\n\tif m % 2 == 1:\n\t\tmove += int(n / 2)\n\treturn move\nprint(domino_piling())\n","(M, N) = map(int, input().split())\nnbofDominos = 0\nif M % 2 == 0:\n\tnbofDominos = M // 2 * N\nelse:\n\tnbofDominos = M * N // 2\nprint(nbofDominos)\n","rawInput = input().split()\nm = int(rawInput[0])\nn = int(rawInput[1])\nprint(m * n // 2)\n","(m, n) = [int(_) for _ in input().split()]\nif m > n:\n\ta = m\n\tm = n\n\tn = a\nans = n // 2 * m + (m // 2 if n % 2 == 1 else 0)\nprint(ans)\n","(a, b) = map(int, input().split())\nc = a * b\nif c % 2 == 0:\n\td = int(c / 2)\n\tprint(d)\nelif c % 2 == 1:\n\td = c - 1\n\te = int(d / 2)\n\tprint(e)\n","list = input().split(' ')\nnum_of_squares = int(list[0]) * int(list[1])\ndominoes = num_of_squares // 2\nprint(dominoes)\n","g = input()\nwerte = g.split()\nflaeche = int(werte[0]) * int(werte[1])\nergebnis = flaeche / 2\nprint(int(ergebnis))\n","(m, n) = map(int, input().split())\nd = 2\nres = m * n / 2\nprint(int(res))\n","nums = list(map(int, input().split()))\nprint(nums[0] * nums[1] // 2)\n","inp = input()\n(row, col) = (int(x) for x in inp.split())\ndomino = row * col * 0.5\nprint(int(domino))\n","(m, n) = map(int, input().split())\nt1 = m // 2 * (n // 1)\nt2 = (m * n - t1 * 2) // 2\nprint(t1 + t2)\n","(a, b) = map(int, input().split())\nif a == 1 and b == 1:\n\tprint(0)\nelse:\n\tn = max(a, b)\n\tm = min(a, b)\n\ts = 0\n\tif m > 1 and n % 2 != 0:\n\t\ts = m // 2\n\tprint(m * (n // 2) + s)\n","mn = list(input().split())\nm = int(mn[0])\nn = int(mn[1])\nquantityOfPlates = int(m * n / 2)\nprint(int(quantityOfPlates))\n","a = str(input())\nif len(a) < 5:\n\tif len(a) > 3:\n\t\tif a[1] != ' ':\n\t\t\tx = a[0] + a[1]\n\t\t\ty = a[3]\n\t\telse:\n\t\t\tx = a[0]\n\t\t\ty = a[2] + a[3]\n\telse:\n\t\tx = a[0]\n\t\ty = a[2]\nelse:\n\tx = a[0] + a[1]\n\ty = a[3] + a[4]\nz = int(y)\nb = int(x)\nprint(int(b * z / 2))\n","X = input().split(' ')\nprint(int(int(X[0]) * int(X[1]) / 2))\n","(n, k) = map(int, input().split())\ns = n * k\ni = 0\nc = 0\nwhile abs(i - s) >= 2:\n\tc = c + 1\n\ti = i + 2\nprint(c)\n","(M, N) = input().split()\n(M, N) = (int(M), int(N))\nans = M * N // 2\nprint(ans)\n","(M, N) = list(map(int, input().split()))\narea = M * N\nmaxno = int(area / 2)\nprint(maxno)\n","import math\nimport itertools\nimport os\nimport sys\nimport re\nimport functools\nimport operator\nprint(functools.reduce(operator.mul, map(int, input().split())) // 2)\n","dimensions = list(map(int, str(input()).split(' ')))\nm = dimensions[0]\nn = dimensions[1]\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\nmini = min(m, n)\nmaxi = m + n - mini\n\ndef fun1(maxi, mini):\n\tcount = maxi // 2\n\tprint(count * mini)\n\ndef fun2(maxi, mini):\n\tcount = maxi // 2\n\tprint(count * mini + mini // 2)\nif maxi % 2 == 0:\n\tfun1(maxi, mini)\nelse:\n\tfun2(maxi, mini)\n","import math\n\ndef read_ints():\n\treturn map(int, input().split())\nn = []\nn = list(read_ints())\nif n[0] % 2 == 0:\n\tans = n[1] * math.floor(n[0] / 2)\nelse:\n\tans = n[1] * math.floor(n[0] / 2) + math.floor(n[1] / 2)\nprint(ans)\n","import sys\nimport math\nn = list(map(int, sys.stdin.readline().split()))\ncount = max(n) * math.floor(min(n) / 2)\nif min(n) % 2 == 1:\n\tcount += math.floor(max(n) / 2)\nprint(int(count))\n","(x, y) = (int(z) for z in input().split())\nprint(int(x * y / 2))\n","import re\nraw = input().split()\ntotal = int(raw[0]) * int(raw[1])\nprint(total // 2)\n","from array import array\nfrom sys import stdin\nimport bisect\n\ndef scan_gen():\n\tfor line in stdin:\n\t\tyield from iter(line.split())\nscan = scan_gen()\n\ndef nint():\n\treturn int(next(scan))\n\ndef nintk(k):\n\treturn tuple((nint() for _ in range(k)))\n\ndef nfloat():\n\treturn float(next(scan))\n\ndef intar_init(size):\n\treturn array('i', [0]) * size\n\ndef intar(size=None):\n\tarr = intar_init(size if size != None else nint())\n\tfor x in range(size):\n\t\tarr[x] = nint()\n\treturn arr\n\ndef solve():\n\t(n, m) = nintk(2)\n\tprint(n * m // 2)\nsolve()\n","from sys import stdin, stdout\n\ndef getInts():\n\treturn map(int, stdin.readline().split())\n\ndef main():\n\t(m, n) = getInts()\n\tans = m * n // 2\n\tprint(ans)\nmain()\n","(a, b) = [int(a) for a in input().split()]\nd = a * b\nprint(d // 2)\n","lista = list(map(int, input().split()))\ntotal = lista[0] * lista[1]\nprint(int(total / 2))\n","(m, n) = [int(s) for s in input().split()]\nif m * n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m * n - 1) / 2))\n","import math\n(m, n) = map(int, input().strip().split())\nprint(math.floor(m * n / 2))\n","(a, b) = input().split()\n(a, b) = (int(a), int(b))\nboard = a * b\nprint(board // 2)\n","mn = input().split(' ')\nba = int(mn[0]) * int(mn[1])\nnum = int(ba / 2)\nprint(num)\n","x_y = input()\nxy = x_y.split()\nxy = list(map(int, xy))\ns = xy[0] * xy[1]\nprint(s // 2)\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\tprint(str(m // 2 * n))\n\texit()\nif n % 2 == 0:\n\tprint(str(n // 2 * m))\n\texit()\ndominos_needed = 0\ndominos_needed += m // 2\ndominos_needed *= n\ndominos_needed += n // 2\nprint(dominos_needed)\n","from sys import stdin\n(w_s, l_s) = stdin.readline().strip().split(' ')\nl = int(l_s)\nw = int(w_s)\nif l % 2 == 1:\n\tnum_even_solns = int((l - 1) * w / 2)\n\tnum_odd_solns = int(w / 2)\n\tprint(num_even_solns + num_odd_solns)\nelse:\n\tnum_even_solns = l * w / 2\n\tprint(int(num_even_solns))\n","from sys import stdin\n(n, m) = stdin.readline().strip().split()\nn = int(n)\nm = int(m)\nif m <= 16 and n <= 16:\n\tt = m * n // 2\n\tprint(t)\n","x = input()\nl = x.split()\nn = int(l[0])\nm = int(l[1])\nif m * n % 2 == 0:\n\tprint(m * n // 2)\nelse:\n\ts = m * n - 1\n\tprint(s // 2)\n","(m, n) = [int(x) for x in input().split()]\nprint(int(m / 2 * (n / 1)))\n","from math import floor\ninp = input()\nlis = inp.split()\nm = int(lis[0])\nn = int(lis[1])\nlol = floor(m * n / 2)\nprint(lol)\n","import math\nvowel_list = ['a', 'e', 'i', 'o', 'u', 'y']\n\ndef watermelon_4a():\n\tnum = int(input())\n\tif num % 2 == 0:\n\t\tif num == 2:\n\t\t\tprint('NO')\n\t\telse:\n\t\t\tprint('YES')\n\telse:\n\t\tprint('NO')\n\treturn\n\ndef theatre_square_1a():\n\tinput_list = read_list(int, input())\n\tlength = input_list[0]\n\twidth = input_list[1]\n\tflagstone = input_list[2]\n\tans_0 = int(math.ceil(length / flagstone))\n\tans_1 = int(math.ceil(width / flagstone))\n\tprint(ans_0 * ans_1)\n\treturn\n\ndef way_to_long_words_71a():\n\tcases = read_int()\n\tfor counter in range(cases):\n\t\tword = input()\n\t\tword_len = len(word)\n\t\tif word_len <= 10:\n\t\t\tprint(word)\n\t\telse:\n\t\t\tprint(word[0] + str(word_len - 2) + word[word_len - 1])\n\treturn\n\ndef next_round_158a():\n\tread_in = read_list(int, input())\n\tparticipant_scores = read_list(int, input())\n\ttotal_participants = read_in[0]\n\tfinish_place = read_in[1]\n\tcounter = 0\n\tif total_participants == 1:\n\t\tif participant_scores[0] == 0:\n\t\t\tprint(0)\n\t\telse:\n\t\t\tprint(1)\n\t\treturn\n\telif participant_scores[finish_place - 1] == 0:\n\t\tfor participant in participant_scores:\n\t\t\tif participant != 0:\n\t\t\t\tcounter += 1\n\telse:\n\t\tfor participant in participant_scores:\n\t\t\tif participant >= participant_scores[finish_place - 1]:\n\t\t\t\tcounter += 1\n\tprint(counter)\n\treturn\n\ndef string_task_118a():\n\tstring = input()\n\tstring = string.lower().replace('a', '').replace('e', '').replace('i', '').replace('o', '').replace('u', '').replace('y', '')\n\tfinal_str = ''\n\tfor letter in string:\n\t\tfinal_str += '.'\n\t\tfinal_str += letter\n\tprint(final_str)\n\treturn\n\ndef domino_piling_50a():\n\tdimensions = read_list(int, input())\n\tlength = dimensions[0]\n\twidth = dimensions[1]\n\tprint(int(math.floor(length * width / 2)))\n\treturn\n\ndef read_list(type_in, line_in):\n\treturn list(map(type_in, line_in.split()))\n\ndef read_int():\n\treturn int(input())\n\ndef main():\n\tdomino_piling_50a()\n\treturn\nmain()\n","a = input().split()\nfor i in range(len(a)):\n\ta[i] = int(a[i])\nd = a[0] * a[1]\nh = d // 2\nprint(h)\n","mas = input().split()\nm = int(mas[0])\nn = int(mas[1])\nprint(int(m * n / 2))\n","(m, n) = [int(i) for i in input().split()]\nif m % 2 == 0 or n % 2 == 0:\n\tans = n * m / 2\nelse:\n\tans = (n * m - 1) / 2\nprint(int(ans))\n","(m, n) = map(int, input().split())\nprod = m * n\nresult = prod // 2\nprint(result)\n","import math\nx = input()\ny = [int(i) for i in x.strip().split()]\nprod = y[0] * y[1]\nnum = prod // 2\nprint(num)\n","i = iter((int(j) for j in input().split()))\nprint(next(i) * next(i) // 2)\n","(a, b) = [int(x) for x in input().split()]\n\ndef main(a, b):\n\tif a % 2 == 0:\n\t\treturn a * b // 2\n\tif b % 2 == 0:\n\t\treturn a * b // 2\n\treturn (a * b - 1) // 2\nprint(main(a, b))\n","(M, N) = [int(x) for x in input().split()]\nsquare = M * N\na = square / 2\nprint(int(a))\n","def solve(m, n):\n\tarea = m * n\n\treturn (area - area % 2) // 2\n(m, n) = map(int, input().split())\nprint(solve(m, n))\n","X = input().split()\nn = int(X[0])\nm = int(X[1])\nprint(n * m // 2)\n","def main():\n\t(n, m) = list(map(int, input().rstrip().split()))\n\tprint(n * m // 2)\nmain()\n","numbers = input()\nc = 0\nfor i in range(len(numbers)):\n\tif numbers[i:i + 1] == ' ':\n\t\tc = i\nm = int(numbers[:c])\nn = int(numbers[c + 1:])\nif m % 2 != 0 or n % 2 != 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(m * n / 2))\n","l = input()\n(n, m) = l.split()\nn = int(n)\nm = int(m)\nres = 0\nif n == m and n == 1:\n\tprint(0)\nelse:\n\ts = n * m\n\tres = s // 2\n\tprint(res)\n","num = input()\nx = num.split()\nnum1 = int(x[0])\nnum2 = int(x[1])\nn = num1 * num2 * (1 / 2)\nprint(int(n))\n","(m, n) = map(int, input().split())\nt = 2 * 1\nb = m * n\nprint(int(b / t))\n","(a, b) = map(int, input().split())\nif a < b:\n\ts = a\n\ta = b\n\tb = s\nimport math\nx = math.floor(a / 2) * b\nif a % 2 == 0:\n\ty = 0\nelse:\n\ty = math.floor(b / 2)\nprint(x + y)\n","(m, n) = map(int, input().split())\nsum = 0\nx = m * n\nwhile x > 1:\n\tx = x - 2\n\tsum = sum + 1\nprint(sum)\n","import math\n\nclass Domino:\n\n\tdef __init__(self, m, n):\n\t\tself.m = m\n\t\tself.n = n\n\n\tdef max_domino(self):\n\t\tp = m * n / 2\n\t\treturn math.floor(p)\n(m, n) = map(int, input().split())\nk = Domino(m, n)\na = k.max_domino()\nprint(a)\n","inp = list(map(int, input().split()))\nif inp[0] % 2 == 0:\n\tprint(int(inp[0] / 2 * inp[1]))\nelse:\n\tanswer = inp[0] // 2 * inp[1]\n\tanswer += inp[1] // 2\n\tprint(answer)\n","(x, y) = input().split(' ')\nx = int(x)\ny = int(y)\np = 0\nif x >= 2 and y >= 1:\n\twhile x >= 2:\n\t\tx = x - 2\n\t\tz = y\n\t\twhile y >= 1:\n\t\t\ty = y - 1\n\t\t\tp = p + 1\n\t\ty = z\n\t\tif x == 1:\n\t\t\tz = x\n\t\t\tx = y\n\t\t\ty = z\nelif y >= 2 and x >= 1:\n\twhile y >= 2:\n\t\ty = y - 2\n\t\tz = x\n\t\twhile x >= 1:\n\t\t\tx = x - 1\n\t\t\tp = p + 1\n\t\tx = z\n\t\tif y == 1:\n\t\t\tz = x\n\t\t\tx = y\n\t\t\ty = z\nprint(p)\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nc = a * b\nif a * b % 2 == 1:\n\tc = a * b - 1\nprint(int(c / 2))\n","q = list(input().split(' '))\nw = int(q[0]) * int(q[1])\nprint(w // 2)\n","(a, b) = map(int, input().split())\ncount = a // 2 * b\nif a % 2 == 1:\n\tcount += b // 2\nprint(count)\n","inp = input()\n(m, n) = inp.split(' ')\n(m, n) = (int(m), int(n))\nflg = 2\n(white, black) = (0, 0)\nfor i in range(m * n):\n\tif flg % 2 == 0:\n\t\tblack += 1\n\telse:\n\t\twhite += 1\n\tflg += 1\nprint(int((white + black) / 2))\n","(n, m) = map(int, input().split())\nif n % 2 == 0 and m % 2 == 1:\n\tprint(n // 2 * m)\nelif m % 2 == 0 and n % 2 == 1:\n\tprint(m // 2 * n)\nelse:\n\tb = 1\n\tif n % 2 == m % 2 == 0:\n\t\tprint(max(n // 2 * m, m // 2 * n))\n\t\tb = 0\n\t(n, m) = (max(n, m) - 1, min(n, m))\n\tif b and n % 2 == 0 and (m % 2 == 1):\n\t\tprint(n // 2 * m + m // 2)\n\telif b and m % 2 == 0 and (n % 2 == 1):\n\t\tprint(m // 2 * n + n // 2)\n","(M, N) = map(int, input('').split())\nA = M * N / 2\nB = int(A)\nprint(B)\n","import math\n(m, n) = [int(x) for x in input().split()]\nif m == 1 and n == 1:\n\tprint(0)\nelse:\n\tprint(math.floor(m * n / 2))\n","n = input().split()\nm = int(n[0])\nn = int(n[1])\na = [0] * 17\na[1] = m // 2\nfor i in range(m + 1):\n\ta[2] = max(a[2], i + (m - i) // 2 * 2)\nfor i in range(n + 1):\n\tfor j in range(i, n + 1 - i):\n\t\ta[i + j] = max(a[i + j], a[i] + a[j])\nprint(a[n])\n","(m, n) = map(int, input().split())\nk = n // 2\np = n % 2\nif p == 0:\n\ts = int(m * n / 2)\nelse:\n\ts = int(m * k + m // 2)\nprint(s)\n","data = input()\n(m, n) = data.split()\nm = int(m)\nn = int(n)\nanswer = 0\nif m % 2 == 0 and n % 1 == 0:\n\tanswer = m * n // 2\nelif m % 2 == 1 and n % 1 == 0:\n\tanswer = m * n // 2\nprint(answer)\n","def main():\n\t(nrows, ncols) = map(int, input().strip().split())\n\tprint(nrows * ncols // 2)\nmain()\n","mn = list(map(int, input().split()))\nb = [[i for i in range(mn[0])] for i in range(mn[1])]\nj = [len(i) for i in b]\nprint(sum(j) // 2)\n","(M, N) = map(int, input().split())\nsq = M * N\nansw = sq // 2\nprint(answ)\n","n = list(map(lambda x: int(x), input().split()))\nprint(n[0] * n[1] // 2)\n","import math\n\ndef DominoPiling(n, m):\n\treturn int(n * m / 2)\npass\n(n, m) = input().split()\nn = int(n)\nm = int(m)\nprint(DominoPiling(n, m))\n","(M, N) = (int(x) for x in input().split())\nremM = M % 2\nremN = N % 2\nif remM == 0 and remN == 0:\n\tmaxNumber = N * (M / 2)\nelif remM == 0 and remN != 0:\n\tmaxNumber = M * (N // 2) + M / 2\nelif remM != 0 and remN == 0:\n\tmaxNumber = N * (M // 2) + N / 2\nelse:\n\tmaxNumber = M * (N // 2) + M // 2\nprint(int(maxNumber))\n","import sys\nimport math\n\ndef alele():\n\treturn list(map(int, sys.stdin.readline().strip().split()))\n\ndef ilele():\n\treturn map(int, sys.stdin.readline().strip().split())\n\ndef input():\n\treturn sys.stdin.readline().strip()\n(A, B) = map(int, input().split(' '))\nprint(A * B // 2)\n","str = input().split()\nm = int(str[0])\nn = int(str[1])\nn_sqaures = 0\nwhile m > 1 or n > 1:\n\tif m // 2 >= n // 2:\n\t\tn_sqaures += m // 2 * n\n\t\tm -= m // 2 * 2\n\telse:\n\t\tn_sqaures += n // 2 * m\n\t\tn -= n // 2 * 2\nprint(n_sqaures)\n","import math\n(l, m) = map(int, input().split())\nprint(math.floor(m * l / 2))\n","h = input()\ni = h.split(' ')\nm = int(i[0])\nn = int(i[1])\nx = m * n // 2\nprint(x)\n","ch = str(input())\nL = ch.split()\nLL = list()\nfor c in L:\n\tLL.append(int(c))\nL = LL\nprint(L[0] * L[1] // 2)\n","area = []\narea = input().split()\nreslt = int(area[0]) * int(area[1]) / 2\nprint(int(reslt))\n","entry = input()\nentry = [int(i) for i in entry.split()]\nn = entry[0]\nm = entry[1]\ndomino = n * m // 2\nprint(domino)\n","def main():\n\tprint(eval('*'.join(input().split())) // 2)\nmain()\n","numbers = input()\nspace_ind = numbers.index(' ')\nbord = int(numbers[:space_ind]) * int(numbers[space_ind:])\nif bord % 2 == 0:\n\ttot = bord / 2\nelse:\n\ttot = (bord - 1) / 2\nprint(int(tot))\n","class main:\n\t(m, n) = input().split()\n\tmm = int(m)\n\tnn = int(n)\n\tsum = mm * nn\n\tres = sum // 2\n\tprint(format(res, '.0f'))\n","(M, N) = input().split(' ')\nMaxDominoes = int(M) * int(N) // 2\nprint(MaxDominoes)\n","(x, y) = map(int, input().split())\narea = x * y\nnumber = area // 2\nprint(number)\n","line = input()\npieces = line.split()\na = int(pieces[0])\nb = int(pieces[1])\nprint(a * b // 2)\n","import math as ma\ninp = tuple(input().split(' '))\nprint(ma.floor(int(inp[0]) / 2 * int(inp[1])))\n","L = input().split()\nM = int(L[0])\nN = int(L[1])\ntotal = M * N - M * N % 2\nres = int(total / 2)\nprint(res)\n","dimensions = list(map(int, input().strip().split()))\narea = dimensions[0] * dimensions[1]\nno_of_domino = area // 2\nprint(no_of_domino)\n","input_size = input().split(' ')\nn_k = [int(x) for x in input_size]\nm = n_k[0]\nn = n_k[1]\nif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int(m * ((n - 1) / 2) + (m - 1) / 2))\n","import math\n(m, n) = [int(i) for i in input().split()]\nif m % 2 == 0 or (m % 2 == 1 and n % 2 == 0):\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m - 1 + (n - 1) + (m - 1) * (n - 1)) / 2))\n","import math\n(m, n) = map(int, input().split())\ndominoArea = 2 * 1\nresult = math.floor(m * n / dominoArea)\nprint(result)\n","def isEven(x):\n\tif x % 2 == 0:\n\t\treturn True\n(x, y) = [int(x) for x in input().split()]\nif isEven(x) == True and isEven(y) == True:\n\tanswer = x * y / 2\nelif isEven(x) == True and isEven(y) != True or (isEven(x) != True and isEven(y) == True):\n\tanswer = x * y / 2\nelif isEven(x) != True and isEven(y) != True:\n\tanswer = x * y / 2 - 0.5\nprint(int(answer))\n","(input_var1, input_var2) = input().split(' ')\nvar1 = int(input_var1)\nvar2 = int(input_var2)\noutput = var1 * var2 // 2\nprint(output)\n","(M, N) = input().split()\nm = int(M)\nn = int(N)\nnum = 0\nif m == 1:\n\tnum = n // 2\nelif m % 2 == 0:\n\tnum = m / 2 * n\nelif n % 2 == 0:\n\tnum = n / 2 * m\nelif n == 1:\n\tnum = n // 2\nelif m > n:\n\tnum = n * (m // 2) + n // 2\nelse:\n\tnum = m * (n // 2) + m // 2\nprint(int(num))\n","import math\ninput_string = input().split()\nn = int(input_string[0])\nm = int(input_string[1])\nprint(str(math.floor(n * m / 2)))\n","def domino(n, m):\n\treturn n * m // 2\n(N, M) = [int(i) for i in input().split()]\nprint(domino(N, M))\n","data = input().split()\narea = int(data[0]) * int(data[1])\nans = area // 2\nprint(ans)\n","s = [int(i) for i in input().split(' ')]\nk = s[1]\nn = s[0]\nprint(k * n // 2)\n","def fuck(a):\n\tk = a[0] * a[1]\n\ts = k // 2\n\tprint(s)\na = [int(x) for x in input().split()]\nfuck(a)\n","field = input().split(' ')\nsquare = int(field[1]) * int(field[0])\ndomino = square // 2\nprint(domino)\n","from math import floor\n\ndef get_values():\n\ttry:\n\t\tmeasurements = list(map(int, input().split()))\n\t\t(m, n) = measurements\n\t\tarea = m * n\n\t\tArea_domino = 2\n\t\tnum_dom = floor(area / Area_domino)\n\t\treturn print(num_dom)\n\texcept ValueError:\n\t\treturn\nget_values()\n","a = list(map(int, input().split()))\nif a[0] % 2 == 0 and a[1] % 2 == 0:\n\tprint(a[0] // 2 * a[1])\nelif a[0] % 2 == 0 and a[1] % 2 == 1:\n\tprint(a[0] // 2 * a[1])\nelif a[0] % 2 == 1 and a[1] % 2 == 0:\n\tprint(a[1] // 2 * a[0])\nelse:\n\tprint(a[0] // 2 * a[1] + a[1] // 2)\n","first_input = input()\nfirst_input1 = first_input.split()\nM = int(first_input1[0])\nN = int(first_input1[1])\nmn = M * N\nprint(int(mn / 2))\n","a = list(map(int, input().split()))\nc = a[0] * a[1]\nz = 0\nif c % 2 == 0:\n\tfor i in range(0, c):\n\t\tif i % 2 == 0:\n\t\t\tz += 1\nelif c % 2 != 0:\n\tfor i in range(1, c):\n\t\tif i % 2 == 0:\n\t\t\tz += 1\nprint(z)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ns = 2 * 1\na = m * n / s\nprint(int(a))\n","import math\nx = input().split()\nn = int(x[0])\nm = int(x[1])\nprint(m * n // 2)\n","def main():\n\t(n, m) = map(int, input().split())\n\tans = n * m / 2\n\tprint(int(ans))\nmain()\n","a = input()\nspace = a.find(' ')\nd = 0\nif a[0:space] != '1' or a[space + 1:] != '1':\n\td = int(a[0:space]) * int(a[space + 1:]) // 2\nprint(d)\n","a = input()\n(m, n) = a.split(' ')\n(m, n) = (int(m), int(n))\nk = m * n\nprint(k // 2)\n","import sys\nterrain = list(map(int, sys.stdin.readline().split()))\nprint(terrain[0] * terrain[1] // 2)\n","import sys\nimport os\nonline = 'ONLINE_JUDGE' in os.environ\n\ndef main():\n\t(m, n) = stdin_get_ints_from_line()\n\tprint(int(m / 2 * n))\n\treturn\n\ndef p(data):\n\tif not online:\n\t\tprint(data)\n\ndef stdin_get_ints_from_line():\n\treturn (int(x) for x in sys.stdin.readline().strip().split(' '))\n\ndef stdin_get_ints_list_from_line():\n\treturn list((int(x) for x in sys.stdin.readline().strip().split(' ')))\n\ndef stdin_get_string_from_line():\n\treturn sys.stdin.readline().strip()\nmain()\n","p = input().split()\nM = int(p[0])\nN = int(p[1])\nn = int(M * N / 2)\nprint(n)\n","a = input()\na = a.split()\nresult = [int(item) for item in a]\nb = result[0]\nc = result[1]\nd = b * c // 2\nprint(d)\n","mn = input()\nh = mn.split()\nA = int(h[0]) * int(h[1])\nprint(int(A / 2))\n","values = [int(i) for i in input('').split(' ')]\nprint(int(values[0] * values[1] / 2))\n","li = list(map(int, input().strip().split()))\nm = li[0]\nn = li[1]\nc = m * n\nc = c // 2\nprint(c)\n","def main():\n\tarea = input().split()\n\tarea = int(area[0]) * int(area[1])\n\tif area % 2 == 1:\n\t\tnodom = (area - 1) / 2\n\telse:\n\t\tnodom = area / 2\n\tprint(int(nodom))\nmain()\n","(m, n) = map(int, input().split())\nif m % 2 == 0:\n\tif n % 2 == 0:\n\t\tt = int(m * n / 2)\n\t\tprint(t)\n\telse:\n\t\tt = int(m / 2 * n)\n\t\tprint(t)\nelif n % 2 == 0:\n\tt = int(n / 2 * m)\n\tprint(t)\nelse:\n\tt = int(m / 2)\n\tt1 = int(n / 2)\n\tprint(t * n + t1)\n","(m, n) = (int(i) for i in input().split())\nh = m // 2\ntotal = h * n\nif m - h * 2 == 1 and n > 1:\n\ttotal += n // 2\nprint(total)\n","import math\nimport collections\nimport bisect\nimport heapq\nimport time\nimport random\nimport itertools\nimport sys\n(N, M) = map(int, input().split())\nif N % 2 == 1 and M % 2 == 1:\n\tprint((N * M - 1) // 2)\nelse:\n\tprint(N * M // 2)\n","input_str = input().split(' ')\na = int(input_str[0])\nb = int(input_str[1])\nres = a * b\nprint(res // 2)\n","a = [int(i) for i in input().split()]\nif a[0] % 2 == 0:\n\tn = 0.5 * a[0] * a[1]\nelif a[1] % 2 == 0:\n\tn = 0.5 * a[0] * a[1]\nelse:\n\tn = 0.5 * a[0] * a[1] - 0.5\nprint(int(n))\n","x = list(map(int, input().split()))\nr = x[0] * x[1]\np = int(r / 2)\nprint(p)\n","[M, N] = [int(i) for i in input().split()]\nif M % 2 == 0:\n\tS = M / 2 * N\nelif N % 2 == 0:\n\tS = N / 2 * M\nelse:\n\tS = M // 2 * N + N // 2\nprint(int(S))\n","field_args = input().split(' ')\nn = int(field_args[0])\nm = int(field_args[1])\nprint(int((m * n - m * n % 2) / 2))\n","n = input().split()\nc = int(n[0])\nr = int(n[1])\ncount = 0\nncount = 0\nfor i in range(r):\n\tif c % 2 != 0:\n\t\tncount += 1\n\tfor x in range(1, c + 1):\n\t\tif x % 2 == 0:\n\t\t\tcount += 1\ncc = 0\nfor i in range(1, ncount + 1):\n\tif i % 2 == 0:\n\t\tcc = cc + 1\nprint(count + cc)\n","def main():\n\tinfo = input().split()\n\tM = int(info[0])\n\tN = int(info[1])\n\treturn M * N // 2\nprint(main())\n","def dominoPiling(m, n):\n\treturn m * n // 2\n(m, n) = map(int, input().split())\nprint(dominoPiling(m, n))\n","from sys import stdin\n\ndef main():\n\t(m, n) = stdin.readline().split()\n\tm = int(m)\n\tn = int(n)\n\ta = int(m / 2 * n)\n\tb = int(m * n / 2)\n\tif a < b:\n\t\tprint(b)\n\telse:\n\t\tprint(a)\nmain()\n","import math\ns = input().split()\n(a, b) = (int(s[0]), int(s[1]))\nresult = math.floor(a * b * 0.5)\nprint(result)\n","(m, n) = map(int, input().split())\nb = m * n\nd = 2\na = int(b / d)\nprint(round(a))\n","line = input()\ndimensions = line.split()\nfor i in range(len(dimensions)):\n\tdimensions[i] = int(dimensions[i])\nsquare = dimensions[0] * dimensions[1]\nif square % 2 == 0:\n\tresult = int(square / 2)\nelse:\n\tresult = int((square - 1) / 2)\nprint(result)\n","(m, n) = map(int, input().strip().split(' '))\ns = 2\na = m * n\nr = a // s\nprint(r)\n","a = input().split()\nl = int(a[0])\nm = int(a[1])\nprint(l * m // 2)\n","def main():\n\tinp = input().split()\n\t(m, n) = (int(inp[0]), int(inp[1]))\n\tMax = n // 2 * m + m // 2 * (n % 2) if n > m else m // 2 * n + n // 2 * (m % 2)\n\tprint(Max)\nmain()\n","(a, b) = map(int, input().split())\nif a == 1:\n\tprint(b // 2)\nelif b == 1:\n\tprint(a // 2)\nelif not a & 1:\n\tprint(a // 2 * b)\nelif not b & 1:\n\tprint(b // 2 * a)\nelse:\n\tprint(a * (b // 2) + a // 2)\n","(l, m) = [int(x) for x in input().split()]\nc = 0\nr = l * m\nwhile r >= 2:\n\tc += 1\n\tr = r - 2\nprint(c)\n","class DominoPiling:\n\n\tdef solve(self, i, j):\n\t\ttileArea = 2 * 1\n\t\tboardArea = m * n\n\t\treturn boardArea // tileArea\n(m, n) = map(int, input().split(' '))\nprint(DominoPiling().solve(m, n))\n","from math import floor\n\ndef domino():\n\t(m, n) = map(int, input().split())\n\tarea = m * n\n\tmaxd = floor(area / 2)\n\treturn maxd\nprint(domino())\n","(a, b) = input().split()\n(a, b) = (int(a), int(b))\nmid = a * b\nansw = mid // 2\nprint(answ)\n","tempInput = input()\nw = int(tempInput.split()[0])\nh = int(tempInput.split()[1])\nprint(int(w * h / 2))\n","n = input()\nn1 = n.split()\ns = int(n1[0]) * int(n1[1])\nprint(s // 2)\n","width = 0\nlength = 0\nDominoWidth = 0\nDominolength = 0\na = 0\n(width, length) = input().split()\nwidth = int(width)\nlength = int(length)\nDominoWidth = int(width)\nDominolength = int(length / 2)\nif length % 2 != 0:\n\ta = 1\nelse:\n\ta = 0\nTotal = Dominolength * DominoWidth + a * int(width / 2)\nprint(int(Total))\n","x = list(input().split())\ntemp = int(x[0]) * int(x[1])\nif temp % 2 != 0:\n\ttemp = temp - 1\ntemp = int(temp / 2)\nprint(temp)\n","(m, n) = map(int, input().split())\nassert 0 <= m <= n <= 16\nk = int(m * n / 2)\nprint(k)\n","import math\n(q, z) = input().split()\nq = int(q)\nz = int(z)\nsp = q * z\nn = math.floor(sp / 2)\nprint(n)\n","from sys import stdin\nA = list(map(int, stdin.readline().split()))\nif A[0] % 2 == 0 or A[1] % 2 == 0:\n\tprint(int(A[0] * A[1] / 2))\nelse:\n\tprint(int((A[0] * A[1] - 1) / 2))\n","(m, n) = map(int, input().split())\nw = max(m, n)\nh = min(m, n)\nres = h * (w // 2) + h // 2 * (w % 2)\nprint(res)\n","from sys import stdin, stdout, exit as sys_ret\n(f_input, f_print, f_flush) = (stdin.readline, stdout.write, stdout.flush)\n(a, b) = map(int, f_input().split())\nf_print(str(a * b // 2))\n","from math import floor as f\nl = list(map(int, input().split()))\nprint(f(l[0] * l[1] * 0.5))\n","n = input().split()\na = int(n[0]) * int(n[1])\nif a % 2 == 1:\n\tprint(int((a - 1) / 2))\nelse:\n\tprint(int(a / 2))\n","(a, b) = map(int, input().split())\narea = a * b\na = area\nif a & 1:\n\tprint((a - 1) // 2)\nelse:\n\tprint(a // 2)\n","(m, n) = map(int, input().split())\nanswer = m * n // (2 * 1)\nprint(answer)\n","string = input()\nnumbers = string.split()\n(a, b) = (int(numbers[0]), int(numbers[1]))\nprint(a * b // 2)\n","temp = input().split()\nn1 = int(temp[0])\nn2 = int(temp[1])\nn = n1 * n2\nnum = int(n / 2)\nprint(num)\n","a = [int(x) for x in input().split(' ')]\nif a[0] % 2 == 0 or a[1] % 2 == 0:\n\tcount = a[0] * a[1] / 2\nelse:\n\tcount = (a[0] * a[1] - 1) / 2\nprint(int(count))\n","(m, n) = input().split(' ')\n(m, n) = (int(m), int(n))\nif m % 2 == 1 and n % 2 == 0 or (m % 2 == 0 and n % 2 == 1):\n\toutput = int(m * n / 2)\nelse:\n\toutput = int((m * n - 1) / 2) if int(m * n / 2) % 2 else int(m * n / 2)\nprint(output)\n","import math\nline = input()\nn = int(line.split(' ')[0])\nm = int(line.split(' ')[1])\ncount = 0\nif n % 2 == 0:\n\tcount += math.floor(n / 2) * m\nelse:\n\tcount += math.floor(n / 2) * m\n\tcount += math.floor(m / 2)\nprint(count)\n","(n, m) = list(map(int, input().split()))\na = 2 * 1\ns = m * n // a\nprint(s)\n","(n, m) = map(int, input().split())\ns = 0\nx2 = n // 2\ny2 = m // 2\ns += x2 * y2 * 2\nif n - x2 * 2 == 1:\n\ts += y2\nif m - y2 * 2 == 1:\n\ts += x2\nprint(s)\n","(n, m) = map(int, input().split())\nif n * m % 2 == 0 or n * m % 2 != 0:\n\tprint(n * m // 2)\n","board_sizes = input().split()\nboard_size_as_int = list(map(lambda inp: int(inp), board_sizes))\n(m, n) = board_size_as_int\nif m * n > 1:\n\tprint(int(m * n / 2))\nelse:\n\tprint(0)\n","inp = input()\ns = inp.find(' ')\nw = int(inp[:s])\nh = int(inp[s:])\nh *= w\nh /= 2\nh = int(h)\nprint(h)\n","(m, n) = map(int, input().split())\no = m * n\nx = o // 2\nprint(x)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nif N % 2 == 0:\n\tk = M * (N // 2)\nelse:\n\tk = M * (N // 2) + M // 2\nprint(k)\n","(m, n) = list(map(int, input().split()))\nimport math\nval = m / 2 * (n / 1)\nval1 = m / 1 * (n / 2)\nprint(int(max(val, val1)))\n","dim = input()\nd = dim.split()\nsize = int(d[0]) * int(d[1]) / 2\nprint(int(size))\n","INPTD = str(input())\nLST = INPTD.split(' ')\nM = int(LST[0])\nN = int(LST[1])\nT = 0\n\ndef count_dominos_row(row_length, is_big_row):\n\tif is_big_row:\n\t\treturn row_length\n\telse:\n\t\treturn row_length // 2\nwhile True:\n\tif N == 1:\n\t\tT += count_dominos_row(M, False)\n\telse:\n\t\tT += count_dominos_row(M, True)\n\tN = N - 2\n\tif N <= 0:\n\t\tbreak\nprint(T)\n","import math\n(w, l) = map(int, input().split())\nout = w * l / 2\nprint(int(out))\n","import math as Math\n(M, N) = map(int, input().split())\nprint(Math.floor(M * N * 0.5))\n","listt = input().split()\nM = int(listt[0])\nN = int(listt[1])\nanswer = str(M * N // 2)\nprint(answer)\n","dim = input().split(' ')\nm = int(dim[0])\nn = int(dim[1])\nif not m % 2:\n\tprint(int(m / 2 * n))\nelif not n % 2:\n\tprint(int(n / 2 * m))\nelse:\n\tprint(int(m // 2 * n + n // 2))\n","(N, M) = map(int, input().split())\nimport math\nz = math.floor(N * M / 2)\nprint(z)\n","input_ = input()\ninput_list = input_.split(' ')\nM = int(input_list[0])\nN = int(input_list[1])\nsurface = M * N\nprint(surface // 2)\n","import sys\ninput = sys.stdin.readline\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef insr():\n\ts = input()\n\treturn list(s[:len(s) - 1])\n\ndef invr():\n\treturn map(int, input().split())\n(m, n) = invr()\nif m % 2 == 1 and n % 2 == 1:\n\tprint((m * n - 1) // 2)\nelse:\n\tprint(m * n // 2)\n","s = str(input())\nlst = s.split(' ')\nk = 0\nif int(lst[1]) % 2 == 0:\n\tk = int(lst[1]) / 2 * int(lst[0])\n\tprint(int(k))\nelse:\n\tk = (int(lst[1]) - 1) / 2 * int(lst[0]) + int(lst[0]) / 2\n\tprint(int(k))\n","a = [int(s) for s in input().split()]\nm = a[0]\nn = a[1]\nk = m * n // 2\nprint(k)\n","(m, n) = map(int, input().split())\n(width, heigth) = (0, 0)\nif m > n:\n\twidth = m\n\theigth = n\nelse:\n\twidth = n\n\theigth = m\nrem = 0 if width % 2 == 0 else int(heigth / 2)\nprint(int(width / 2) * heigth + rem)\n","from math import floor\nvals = list(map(int, input().split()))\nprint(floor(vals[0] * vals[1] / 2))\n","(m, n) = map(int, input().split())\nm = int(m)\nn = int(n)\nv = m // 2 * n\nh = m % 2 * (n // 2)\nprint(v + h)\n","from math import floor\n(M, N) = [int(i) for i in input().split()]\nprint(floor(M * N / 2))\n","e = input().split()\na = int(e[0])\nb = int(e[1])\ns = a * b\nprint(int(s / 2))\n","(a, b) = map(int, input().split())\nt = a * b // 2\nprint(t)\n","import sys\nuserInput = sys.stdin.readlines()\na = list(map(int, userInput[0][:-1].split(' ')))\n(m, n) = (a[0], a[1])\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\nif m == 1 and n == 1:\n\tresult = 0\nelse:\n\tN = n // 2\n\tN_ = n % 2\n\tM = m // 2\n\tM_ = m % 2\n\tif N_ == 0:\n\t\tresult = m * N\n\telse:\n\t\tresult = m * N + M\nprint(result)\n","def fnc(m, n):\n\tif m % 2 == 0:\n\t\treturn n * int(m / 2)\n\telse:\n\t\treturn n * int(m / 2) + int(n / 2)\nt = list(map(int, input().strip().split()))\nprint(fnc(t[0], t[1]))\n","string = input()\nM = string.split(' ')\npro = int(M[0]) * int(M[1])\nprint(int(pro / 2))\n","from math import floor\nraw_data = input().split()\nlength = int(raw_data[0])\nheight = int(raw_data[1])\ndlength = 2\ndheight = 1\nvert_spacing = length / dlength\nif vert_spacing % 2 != 0:\n\tvert_spacing = floor(vert_spacing)\nhoriz_spacing = height / dheight\nif horiz_spacing % 2 != 0:\n\thoriz_spacing = floor(horiz_spacing)\nthird_spacing = 0\nif length - vert_spacing * dlength == 1:\n\tthird_spacing = height / dlength\n\tif third_spacing % 2 != 0:\n\t\tthird_spacing = floor(third_spacing)\nnumber_of_dominos = horiz_spacing * vert_spacing + third_spacing\nnumber_of_dominos = int(number_of_dominos)\nprint(number_of_dominos)\n","while True:\n\t(M, N) = map(int, input().split(' '))\n\tif M >= 1 and M <= N and (N <= 16):\n\t\tbreak\nif N % 2 == 0:\n\tprint(int(N / 2) * M)\nelse:\n\tprint(int(N / 2) * M + int(M / 2))\n","(m, n) = [int(i) for i in input().split()]\ndom = int(m * n / 2)\nprint(dom)\n","def solve(t):\n\treturn t['m'] * t['n'] // 2\ntc = {}\n(tc['m'], tc['n']) = [int(s) for s in input().split(' ')]\nprint('{}'.format(solve(tc)))\n","(m, n) = map(int, input().split())\na = m * n\nd = a // m * a // n\nprint(d // 2)\n","(M, N) = map(int, input().split(' '))\nif N % 2 == 1:\n\tans = int(M / 2)\n\tans += M * int((N - 1) / 2)\nelse:\n\tans = M * int(N / 2)\nprint(ans)\n","def main():\n\tnm = [int(number) for number in input().split(' ')]\n\tprint(nm[0] * nm[1] // 2)\nmain()\n","(m, n) = map(int, input().split())\nx = 0\ny = 0\nz = 0\nif m == 1 and n == 1:\n\tprint('0')\nif m == 1 and n >= 2 or (n == 1 and m >= 2):\n\tif m > n:\n\t\tprint(m // 2)\n\telse:\n\t\tprint(n // 2)\nelif m >= 2 and n >= 2:\n\tx = m // 2\n\ty = n\n\tz = x * y\n\tif m % 2 != 0:\n\t\tz = z + n // 2\n\tprint(z)\n","(m, n) = map(int, input().split())\ndomino = 0\nif m < 2 and n < 2:\n\tdomino = domino\nelif m % 2 == 0 or n % 2 == 0:\n\tdomino = n * m // 2\nelse:\n\tdomino = n * m // 2\nprint(domino)\n","s = input().split()\na = int(s[0])\nb = int(s[1])\ntemp = a * b\nans = temp // 2\nprint(ans)\n","import math\n(n, m) = map(int, input().strip().split())\nif n * m == 1:\n\tprint('0')\nelse:\n\tif n % 2 == 0 or m % 2 == 0:\n\t\tmax_dom = n * m / 2\n\telse:\n\t\tmax_dom = n * m / 2 - 1 / 2\n\tprint(int(max_dom))\n","board = input().split(' ')\nnumberOfDominos = int(board[0]) * int(board[1]) // 2\nprint(numberOfDominos)\n","t = 0\nwhile t == 0:\n\t(a, b) = map(int, input().split(' '))\n\tif 1 <= a <= b <= 16:\n\t\tsuma = 0\n\t\tr = a % 2\n\t\tt = a // 2\n\t\tt = t * b\n\t\tsuma += t\n\t\tif r == 1:\n\t\t\tsuma += b // 2\n\t\tprint(suma)\n\t\tt = 1\n\telse:\n\t\tt = 0\n","(N, M) = input().split(' ')\nn = int(N)\nm = int(M)\nres = int(n * m / 2)\nprint(res)\n","angka = input().split()\nM = int(angka[0])\nN = int(angka[1])\nkali = M * N\nhasil = kali // 2\nprint(hasil)\n","(m, n) = map(int, input().strip().split())\ncount = m // 2 * n\nif m % 2 != 0:\n\tcount += n // 2\nprint(count)\n","(m, n) = tuple(map(int, input().split(' ')))\nans = m * n // 2\nprint(ans)\n","import math\n(a, b) = input().split(' ')\narea = int(a) * int(b)\nprint(math.trunc(area / 2))\n","(m, n) = [int(val) for val in input().split()]\nprint(int(m * n / 2))\n","[m, n] = [int(_) for _ in input().split()]\nprint(m * n >> 1)\n","(m, n) = map(int, input().split())\nmn = m * n\nnoDom = int(mn / 2)\nprint(noDom)\n","dim = input()\n(m, n) = dim.split()\nm = int(m)\nn = int(n)\nbig = m * n\nans = int(big // 2)\nprint(ans)\n","mnStr = input()\nmnLs = mnStr.split()\nm = int(mnLs[0])\nn = int(mnLs[1])\nans = m * n // 2\nprint(ans)\n","l = list(map(int, input().split()))\ns = l[0] * l[1]\nprint(s // 2)\n","from functools import reduce\ntotal = reduce(lambda x, y: x * y, [int(x) for x in input().split(' ')])\nprint((total - total % 2) // 2)\n","(w, n) = list(map(int, input().split(' ')))\nprint(w * n // 2)\n","inp = input().split()\na = int(inp[0]) * int(inp[1])\na = a // 2\nprint(a)\n","(m, n) = tuple(map(int, input().split()))\n(a, b) = (m // 2, n // 2)\nprint(a * b * 2 + (m * n - 4 * a * b) // 2)\n","a = input().split()\nq = int(a[0])\nw = int(a[1])\nr = q * w / 2\nc = int(r)\nprint(c)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 0:\n\tl1 = int(m / 2)\n\tt = l1 * n\nelif n % 2 == 0:\n\tl1 = int(n / 2)\n\tt = l1 * m\nelse:\n\tl1 = int(m / 2) * n\n\tl2 = int(n / 2)\n\tt = l1 + l2\nprint(t)\n","rect = list(map(int, input().split()))\nx = rect[0] * rect[1]\ny = 2\nz = x // y\nprint(z)\n","import math\n(m, n) = map(int, input().split())\np = m * n\nif p % 2 == 0:\n\tprint(int(p / 2))\nelse:\n\tk = p - 1\n\tprint(int(k / 2))\n","wt = input().split()\nprint(int(wt[0]) * int(wt[1]) // 2)\n","list = input().split()\nk = 1\nfor i in list:\n\tk *= int(i)\nprint(k // 2)\n","from sys import stdin, stdout\n(m, n) = (int(x) for x in stdin.readline().split())\nprint(m * n // 2)\n","mn = input()\nMN = mn.split(' ')\nM = int(MN[0])\nN = int(MN[1])\nmaximun = int()\nif M % 2 == 1:\n\tm = M // 2\n\tn = N // 2\n\tmaximun = int(m * N + n)\nelse:\n\tmaximun = int(M / 2 * N)\nprint(maximun)\n","def main():\n\t(x, y) = map(int, input().split())\n\tprint(int(x * y / 2))\nmain()\n","(n, m) = [int(i) for i in input().split()]\nhorizontal = n // 2\nh_rem = n % 2\nvertical = 0\nif h_rem > 0:\n\tvertical = m // 2\nprint(horizontal * m + vertical)\n","d = input().split(' ')\nn = int(d[0])\nm = int(d[1])\nprint(m * (n // 2) + n % 2 * (m // 2))\n","(n, m) = map(int, input().split())\nif m > n:\n\tx = n\n\tn = m\n\tm = x\nc = m // 2 * n + m % 2 * (n // 2)\nprint(c)\n","(m, n) = map(int, input().split())\ncount = 0\nfor i in range(1, n * m):\n\tif i * 2 <= n * m:\n\t\tcount = count + 1\n\telse:\n\t\tbreak\nprint(count)\n","(m, n) = map(int, input().split())\nif m >= n:\n\t(m, n) = (n, m)\na = int(m // 2)\nb = m - 2 * a\nc = int(n // 2)\ns = a * n + b * c\nprint(s)\n","(M, N) = map(int, input().split())\noutput = M * N // 2\nprint(output)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nb = M * N\nif b % 2 == 0:\n\ts = b / 2\nelse:\n\ts = (b - 1) / 2\ns = int(s)\nprint(s)\n","def main():\n\tip = input()\n\t(M, N) = [int(i) for i in ip.split()]\n\tprint(M * N // 2)\nmain()\n","inp = input().split(' ')\nn = int(inp[0])\nm = int(inp[1])\ndom = 0\nif int(n) % 2 == 0 or int(m) % 2 == 0:\n\tdom = m * n / 2\nelse:\n\tdom = (n - 1) / 2 * m + (m - 1) / 2\nprint(int(dom))\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nAr = a * b\nA = Ar / 2\nprint(int(A))\n","import math\n(m1, n1) = map(int, input().split())\nm = max(m1, n1)\nn = min(m1, n1)\nk = math.floor(n / 2) * m\nif n % 2:\n\tk += math.floor(m / 2)\nprint(k)\n","def main():\n\t(m, n) = [int(x) for x in input().split()]\n\tif m <= 1 and n <= 1:\n\t\tprint(0)\n\telse:\n\t\tmax_dominos = {(1, 1): 0}\n\t\t(i, j) = (1, 1)\n\t\twhile i < m or j < n:\n\t\t\tif i < m:\n\t\t\t\ti += 1\n\t\t\t\tarea = i * j\n\t\t\t\tcovered_area = max_dominos[i - 1, j] * 2\n\t\t\t\tuncovered = area - covered_area\n\t\t\t\tmax_dominos[i, j] = max_dominos[i - 1, j] + uncovered // 2\n\t\t\tif j < n:\n\t\t\t\tj += 1\n\t\t\t\tarea = i * j\n\t\t\t\tcovered_area = max_dominos[i, j - 1] * 2\n\t\t\t\tuncovered = area - covered_area\n\t\t\t\tmax_dominos[i, j] = max_dominos[i, j - 1] + uncovered // 2\n\t\tprint(max_dominos[m, n])\nmain()\n","(n, m) = list(map(int, input().split()))\nans = n // 2 * m\nif n > 0 and n % 2 != 0:\n\tans = ans + m // 2\nprint(ans)\n","from math import ceil\nfrom math import floor\n\ndef mod_expo(n, p, m):\n\tresult = 1\n\twhile p != 0:\n\t\tif p % 2 == 1:\n\t\t\tresult = result * n % m\n\t\tp //= 2\n\t\tn = n * n % m\n\treturn result\n\ndef find_least_diff(n):\n\tA = 2 * (pow(2, n / 2 - 1) - 1)\n\tB = -pow(2, n / 2)\n\treturn int(abs(B - A))\n\ndef find_ways(n):\n\treturn (n - 1) // 2\n\ndef count_possibilities(n, m):\n\tA = mod_expo(2, m, pow(10, 9) + 7)\n\treturn mod_expo(A - 1, n, pow(10, 9) + 7)\n\ndef min_string(n, k, text):\n\ttext = sorted(text)\n\tif text[0] == text[k - 1]:\n\t\tprint(''.join((text[i] for i in range(k - 1, n))))\n\telse:\n\t\tprint(text[k - 1])\n\ndef get_board(n, m, mat):\n\tfor i in range(n):\n\t\tfor j in range(m):\n\t\t\tprint(i, j)\n\t\t\tif mat[i][j] == '.':\n\t\t\t\tif (j > 0 and mat[i][j - 1] != 'B') and (i > 0 and mat[i - 1][j] != 'B'):\n\t\t\t\t\tmat[i][j] = 'B'\n\t\t\t\telse:\n\t\t\t\t\tmat[i][j] = 'W'\n\tfor i in range(n):\n\t\tfor j in range(m):\n\t\t\tprint(mat[i][j])\nt = 1\nwhile t:\n\tt = t - 1\n\tcount = 0\n\tpx = []\n\tpy = []\n\t(n, m) = map(int, input().split())\n\tprint(floor(n * m / 2))\n","dom = [int(x) for x in input().split()]\nprint(dom[0] * dom[1] // 2)\n","l = lambda : map(int, input().split())\n(m, n) = l()\nprint(m * n // 2)\n","def solve(m, n):\n\tprint(m * n // 2)\nfor _ in range(1):\n\t(m, n) = map(int, input().split())\n\tsolve(m, n)\n","def main():\n\t(M, N) = input('').split()\n\t(M, N) = (int(M), int(N))\n\tarea = M * N\n\tdomino_count = int(area / 2)\n\tprint(domino_count)\nmain()\n","inp = input()\nl = inp.split()\ntotal = int(l[0]) * int(l[1])\nnum = total // 2\nprint(num)\n","(M, N) = map(int, input().split())\ns = M * N\nn = s // 2\nprint(n)\n","def main1():\n\tn = list(map(int, input().rstrip().split()))\n\tprint(n[0] * n[1] // 2)\nmain1()\n","(m, n) = map(int, input().split())\n\ndef is_even(x):\n\treturn x % 2 == 0\nif is_even(m) or is_even(n):\n\tprint(m * n // 2)\nelse:\n\tprint((m * n - 1) // 2)\n","nm = [int(i) for i in input().split(' ')]\nprint(nm[0] * nm[1] // 2)\n","(M, N) = map(int, input().split())\nS = M * N\nif S % 2 == 0:\n\tb = S // 2\n\tprint(b)\nelse:\n\tb = S // 2\n\tprint(b)\n","(n, m) = [int(x) for x in input().split()]\ntotArea = n * m\nprint(int(totArea / 2))\n","try:\n\t(N, M) = map(int, input().split())\n\tprint(N * M // 2)\nexcept EOFError:\n\tpass\n","(m, n) = [int(x) for x in input().split()]\narea = m * n\nmx = area // 2\nprint(mx)\n","domino = input().split(' ')\na = int(domino[0])\nb = int(domino[1])\nx = int(a * b / 2)\nprint(x)\n","mnStr = input()\n(m, n) = [int(ch) for ch in mnStr.split()]\nmatrixCells = m * n\nif matrixCells % 2 == 0:\n\tprint(int(matrixCells / 2))\nelse:\n\tprint(int((matrixCells - 1) / 2))\n","import math\n(m, n) = map(int, input().split())\n\ndef domino(m, n):\n\tx = m * n\n\treturn math.floor(x / 2)\nprint(domino(m, n))\n","brett = input().split()\na = int(brett[0]) * int(brett[1])\nanzahl = int(a / 2)\nprint(anzahl)\n","i = lambda : map(int, input().split())\n(n, k) = i()\nfinal = int(n * k // 2)\nprint(final)\n","from math import floor\n\ndef domino_spill(m, n):\n\tif m * n == 1:\n\t\treturn 0\n\tif n == 1:\n\t\treturn floor(m / 2)\n\tif n == 0:\n\t\treturn 0\n\tif m % 2 == 0:\n\t\treturn m // 2 + domino_spill(m, n - 1)\n\telse:\n\t\treturn m + domino_spill(m, n - 2)\ninp = input()\n(m, n) = [int(i) for i in inp.split(' ')]\nprint(domino_spill(m, n))\n","(x, y) = input().split()\nc = int(x) * int(y)\na = 0\ncnt = -1\nwhile a <= c:\n\ta = a + 2\n\tcnt = cnt + 1\nprint(cnt)\n","dimensions = str(input()) + ' '\ndimensionslist = []\nword = ''\nfor char in dimensions:\n\tif char != ' ':\n\t\tword += char\n\telse:\n\t\tdimensionslist.append(int(word))\n\t\tword = ''\nm = dimensionslist[0]\nn = dimensionslist[1]\nif m * n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m * n - 1) / 2))\n","line = input()\n(a, b) = (int(line.split(' ')[0]), int(line.split(' ')[1]))\nresult = 0\nresult += a / 1 * int(b / 2)\nresult += int(a / 2) * int(b % 2)\nprint(int(result))\n","nums = [int(x) for x in input().split()]\nM = nums[0]\nN = nums[1]\nboard_area = M * N\ndom_area = 2\nprint(board_area // dom_area)\n","CiagZKlawiatury = input().split(' ')\nN = int(CiagZKlawiatury[0])\nM = int(CiagZKlawiatury[1])\nWynik = N * M // 2\nprint(Wynik)\n","(m, n) = list(map(int, input().split()))\nb = m * n\nprint(b // 2)\n","side = list(map(int, input().split()))\narea = side[0] * side[1]\ndomino = area // 2\nprint(domino)\n","strink = str(input())\n(m, n) = strink.split()\nm = int(m)\nn = int(n)\ncount = 0\nif m % 2 == 0:\n\tcount = count + m // 2 * n\nelif n % 2 == 0:\n\tcount = count + n // 2 * m\nelse:\n\tcount = count + m // 2 * n + n // 2\nprint(count)\n","(n, a) = input().split()\nsq_inp = int(n) * int(a)\nprint(sq_inp // 2)\n","a = list(map(int, input().split(' ')))\nlength = a[0]\nbreadth = a[1]\nno_of_dominoes = int(length * breadth / 2)\nprint(no_of_dominoes)\n","(n, m) = map(int, input().split())\ns = n * m\ns1 = 2 * 1\nk = s // s1\nprint(k)\n","(M, N) = map(int, input().strip().split())\nif not M * N % 2 == 0:\n\tprint(int((M * N - 1) / 2))\nelse:\n\tprint(int(M * N / 2))\n","square = input()\nsquare = square.split(' ')\nM = int(square[0])\nN = int(square[1])\ndominos = M * N // 2\nprint(dominos)\n","(r, c) = [int(x) for x in input().split()]\nrO = r % 2 == 1\ncO = c % 2 == 1\nrr = r - 1 if rO else r\ncc = c - 1 if cO else c\nprint(str(rr * cc // 2 + (rr // 2 if cO else 0) + (cc // 2 if rO else 0)))\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\narea = m * n\ndomino = math.floor(area / 2)\nprint(domino)\n","import math\n(n, m) = input().split()\n(n, m) = [int(n), int(m)]\nsa = n * m\nprint(math.floor(sa / 2))\n","board = input()\nboard = board.split(' ')\nm = board[0]\nn = board[1]\nm = m.replace(' ', '')\nn = n.replace(' ', '')\ntile = int(m) * int(n)\ndom = tile // 2\nprint(dom)\n","(m, n) = [int(x) for x in input().split()]\nif m * n == 1:\n\tprint(0)\nelse:\n\ta = max(m, n)\n\tx = a // 2\n\tr = a % 2\n\tprint(x * (m + n - a) + r * ((m + n - a) // 2))\n","class Solution:\n\n\tdef __init__(self, m: int, n: int) -> None:\n\t\tself.m = m\n\t\tself.n = n\n\n\tdef pileUp(self):\n\t\treturn self.m * self.n // 2\n\ndef main():\n\t(m, n) = map(int, input().strip().split())\n\tsolution = Solution(m, n)\n\tprint(solution.pileUp())\nmain()\n","def dominos(m, n):\n\tx = 0\n\tif m % 2 == 0:\n\t\tx = m // 2 * n\n\telse:\n\t\tx = m // 2 * n + n // 2\n\treturn x\n(m, n) = map(int, input().split())\nprint(dominos(m, n))\n","import math\n(x, y) = map(int, input().split(' '))\na = x * y\nans = math.floor(a / 2)\nprint(ans)\n","input_list = []\nnum = 0\nwhile True:\n\tif num == 1:\n\t\tbreak\n\tline = input().split()\n\tline = list(map(int, line))\n\tinput_list.append(line)\n\tnum += 1\nprint(input_list[0][0] * input_list[0][1] // 2)\n","l = list(map(int, input().split()))\nM = l[0]\nN = l[1]\na = M * N\nif M <= 16 and N <= 116 and (M >= 1) and (N >= 1):\n\tif M % 2 == 0 or N % 2 == 0:\n\t\tx = a / 2\n\tif M % 2 != 0 or N != 0:\n\t\tx = a // 2\nprint(x)\n","import math\n(a, b) = [int(i) for i in str.split(input())]\ns = a * b\nprint(math.floor(s / 2))\n","t = input()\nl = list(map(int, t.split(' ')))\nn = l[0] * l[1]\nif n % 2 == 0:\n\tprint(int(n / 2))\nelse:\n\tprint(int((n - 1) / 2))\n","(m, n) = map(int, input().split())\nd = 2\n\ndef domino():\n\tprint(n * m // 2)\ndomino()\n","(m, n) = map(int, input().strip().split(' '))\ndomino_size = 2\nprint(int(m * n / domino_size))\n","import math\n(x, n) = map(int, input().split())\nprint(math.floor(x * n / 2))\n","(m, n) = map(int, input().split())\ncount = 0\nif m % 2 != 0 and n != 0:\n\tprint(m * n // 2)\nelse:\n\tprint(m * n // 2)\n","def main():\n\t(m, n) = list(map(int, input().split()))\n\tprint(m * n // (2 * 1))\nmain()\n","(m, n) = tuple(map(int, input().split(' ')))\nt = m * n\ni = 0\nwhile t > 1:\n\tt -= 2\n\ti += 1\nprint(i)\n","a = [int(i) for i in input().split()]\nt = (a[0] * a[1] - 0.4) / 2\nprint('{:.0f}'.format(t))\n","k = input()\nk = k.split()\nfor x in range(2):\n\tk[x] = int(k[x])\nprint(int(k[1] * k[0] / 2))\n","(a, b) = input().split(' ')\n(a, b) = (int(a), int(b))\nprint(str(a * b // 2))\n","[n, m] = [int(a) for a in input().split(' ')]\ndominos = n * m // 2\nprint(dominos)\n","while True:\n\ta = list(map(int, input().split()))\n\tif a[1] % 2 == 0:\n\t\tp = a[1] // 2 * a[0]\n\telse:\n\t\tp = a[1] // 2 * a[0] + a[0] // 2\n\tbreak\nprint(p)\n","(m, n) = [int(x) for x in input().split()]\nminval = min(m, n)\nmaxval = max(m, n)\nd = minval // 2\nr = minval % 2\ns = maxval // 2\nsquares = maxval * d + r * s\nprint(squares)\n","size = input('').split()\nsize = int(size[0]) * int(size[1])\nfor i in range(0, size + 1, 2):\n\tpass\nprint(i // 2)\n","(m, n) = input().split(' ')\nc = 0\nx = int(m) * int(n)\nwhile x > 1:\n\tx -= 2\n\tc += 1\nprint(c)\n","str1 = input()\nstr1 = list(str1.split(' '))\nn = int(str1[0])\nm = int(str1[1])\nk = m * n\nprint(k // 2)\n","import math\na = input().split()\nprint(math.floor(int(a[0]) * int(a[1]) / 2))\n","crap = input().split()\nprint(int(crap[0]) * int(crap[1]) // 2)\n","from functools import reduce\nimport os\nimport sys\nfrom math import *\nfrom collections import *\nfrom fractions import *\nfrom bisect import *\nfrom heapq import *\nfrom io import BytesIO, IOBase\ninput = lambda : sys.stdin.readline().rstrip('\\r\\n')\n\ndef value():\n\treturn tuple(map(int, input().split()))\n\ndef arr():\n\treturn [int(i) for i in input().split()]\n\ndef sarr():\n\treturn [int(i) for i in input()]\n\ndef inn():\n\treturn int(input())\nmo = 1000000007\n(m, n) = value()\nprint(m * n // 2)\n","(m, n) = map(int, input().split())\narea = m * n\nd = area // 2\nprint(d)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 0:\n\tanswer = n * (m / 2)\n\tprint(int(answer))\nelif m % 2 != 0 and n % 2 == 0:\n\tanswer = m * (n / 2)\n\tprint(int(answer))\nelif m % 2 != 0 and n % 2 != 0:\n\tanswer = max(m * (n / 2), n * (m / 2))\n\tprint(int(answer))\n","arr = [int(i) for i in input().split(' ')]\nprint(arr[0] * arr[1] // 2)\n","import math\nip = input()\n(m, n) = (int(ip.split(' ')[0]), int(ip.split(' ')[1]))\nif m > n or n > 16 or m < 1:\n\tprint('')\nres = math.floor(m * n / 2)\nprint(res)\n","import sys\n(M, N) = list(map(int, sys.stdin.read().split()))\nboth_even = M % 2 == 0 or N % 2 == 0\nif both_even:\n\tprint(int(M * N / 2))\nelse:\n\tprint(int((M * N - 1) / 2))\n","(r, s) = list(map(int, input().split()))\nt = 2 * 1\nba = r * s\nprint(ba // t)\n","(l, b) = map(int, input().split())\nfill = int(l * b / 2)\nprint(fill)\n","k = input()\nl = list(k.split())\ni = 0\nwhile i < len(l):\n\tl[i] = int(l[i])\n\ti += 1\nm = l[0]\nn = l[1]\ns = m * n\nprint(int(s / 2))\n","import math\n(N, M) = map(int, input().split())\nif M * N == 1:\n\tprint(0)\n\texit()\nif M * N % 2 == 0:\n\tprint(int(M * N / 2))\nelse:\n\tprint(math.ceil(M * N / 2) - 1)\n","string = input()\nnumbers = string.split()\nm = int(numbers[0])\nn = int(numbers[1])\nx = m * n // 2\nprint(x)\n","m = ''\nn = ''\nfor (m, n) in (str(input()).split(),):\n\tresult = int(m) * int(n) // 2\n\tprint(result)\n","import math\ninp = input()\ninp.split(' ')\nn = int(inp[0:2])\nm = int(inp[2:5])\nfinal = n * m\nfinal1 = final / 2\nprint(math.floor(final1))\n","(M, N) = list(map(int, input().split()))\nresult = M * N\nwhile result % 2 != 0:\n\tresult -= 1\nelse:\n\tprint(result // 2)\n","(m, n) = list(map(int, input().split()))\narea = m * n\nd = 2\nif area % d == 0:\n\tprint(int(area / d))\nelif area % d != 0:\n\tprint(int(area / d))\n","(m, n) = map(int, input().split())\nl = 0\nwhile n != 0:\n\tif n > 1:\n\t\tl += m\n\t\tn = n - 2\n\telse:\n\t\tl += m // 2\n\t\tn = n - 1\nprint(l)\n","(x, y) = input().split()\nx = int(x)\ny = int(y)\nz = x * y\ndominoes = z // 2\nprint(dominoes)\n","import math\nA = input()\nB = A.split(' ')\n[m, n] = [int(i) for i in B]\nprint(math.floor(m * n / 2))\n","inp = input().split()\nx = int(inp[0])\ny = int(inp[1])\nanswer = x * y / 2\nprint(int(answer))\n","str1 = input()\na = int(str1.split()[0])\nb = int(str1.split()[1])\nprint(a * b // 2)\n","from math import floor\ndominoes = 0\nmn = str(input())\nm = int(mn.split(' ')[0])\nn = int(mn.split(' ')[1])\nshorter = min(m, n)\nif shorter > 1:\n\tdominoes = max(m, n) * floor(shorter / 2)\n\tif not (shorter / 2).is_integer():\n\t\tdominoes += floor(max(m, n) / 2)\nelse:\n\tdominoes = floor(max(m, n) / 2)\nprint(dominoes)\n","(M, N) = map(int, input().split())\namt = M * N // 2\nprint(amt)\n","(a, b) = [int(x) for x in input().split()]\nif not a or not b:\n\tprint('0')\nelse:\n\tp = a * b\n\tp = int(p // 2)\n\tprint(p)\n","(m, n) = map(int, input().split())\ndomino_size = 2 * 1\nboard_size = m * n\ncount = board_size // domino_size\nprint(count)\n","a = input()\nm = ''\nn = ''\nc = 0\nl = len(a)\nfor i in range(0, l):\n\tif c == 0:\n\t\tif a[i] != ' ':\n\t\t\tm = m + a[i]\n\t\tif a[i] == ' ':\n\t\t\tc = 1\n\tif c == 1:\n\t\tc = 2\n\t\tcontinue\n\tif c == 2:\n\t\tn = n + a[i]\nm = int(m)\nn = int(n)\nif n % 2 == 0:\n\tc = n / 2 * m\nelse:\n\tc = (n - 1) / 2 * m + m // 2\nprint(int(c))\n","dims = input()\n(m, n) = dims.split(' ')\nm = int(m)\nn = int(n)\ndominos = m * n // 2\nprint(dominos)\n","(n, m) = map(int, input().split())\nif m * n % 2 == 0:\n\td = m * n // 2\n\tprint(d)\nelif m * n % 2 != 0:\n\te = int(m * n / 2)\n\tprint(e)\n","inp = input().split()\ns = int(inp[0]) * int(inp[1])\nprint(s // 2)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nres = M * N // (2 * 1)\nprint(res)\n","(m, n) = input().split()\navailableSquares = int(m) * int(n)\nDominos = 0\nif availableSquares % 2 != 0:\n\tDominos = (availableSquares - 1) / 2\nelif availableSquares % 2 == 0:\n\tDominos = availableSquares / 2\nprint(int(Dominos))\n","a_b = input()\na = int(a_b.split()[0])\nb = int(a_b.split()[1])\nprint(a * b // 2)\n","s = input().split(' ')\nb = int(s[0]) * int(s[1])\nif b % 2:\n\tprint(int((b - 1) / 2))\nelse:\n\tprint(int(b / 2))\n","import math\n(m, n) = [int(x) for x in input().split()]\na = math.ceil(m * n)\nb = math.ceil(a // 2 * 1)\nprint(b)\n","inp = [int(i) for i in input().split()]\nM = inp[0]\nN = inp[1]\nif M % 2 == 0 or N % 2 == 0:\n\tmx = int(M * N / 2)\nelse:\n\tmx = int((M - 1) * N / 2 + (N - 1) / 2)\nprint(mx)\n","__author__ = 'Bian'\ninput = str(input()).split()\nm = int(input[0])\nn = int(input[1])\nif m % 2 == 0 or n % 2 == 0:\n\tout = m * n / 2\nelif m == 1 and n == 1:\n\tout = 0\nelif m >= n:\n\tout = m // 2 * n + n // 2\nelse:\n\tout = n // 2 * m + m // 2\nprint(int(out))\n","numbers = [int(d) for d in input().split(' ')]\nn = numbers[0]\nm = numbers[1]\nsize = n * m\nprint((size - size % 2) // 2)\n","dimensions = str(input()).split()\nboard = []\nM = int(dimensions[0])\nN = int(dimensions[1])\ntotal = 0\nif M % 2 == 0 or N % 2 == 0:\n\ttotal = M * N // 2\nelse:\n\ttotal = (M - 1) * N // 2 + (N - 1) // 2\nprint(total)\n","text = input()\ntext = text.split()\nt_l = []\nfor i in text:\n\tt_l.append(int(i))\nm = t_l[0]\nn = t_l[1]\nmul = m * n\nprint(mul // 2)\n","(M, N) = map(int, input().split())\nl = M * N\nw = l // 2\nprint(w)\n","inps = input().split()\n(col, row) = (int(inps[0]), int(inps[1]))\nif col % 2 != 0:\n\tdoms = int(col / 2) * row + int(row / 2)\nelse:\n\tdoms = int(col / 2) * row\nprint(doms)\n","inp = input('')\nlistaa = inp.split()\ndim = int(listaa[0]) * int(listaa[1])\nprint(dim // 2)\n","(n, k) = map(int, input().split())\nboardSize = n * k\nif boardSize % 2 == 0:\n\tprint('{:.0f}'.format(boardSize / 2))\nelse:\n\tprint('{:.0f}'.format((boardSize - boardSize % 2) / 2))\n","import sys\nnumbers = [int(i) for i in sys.stdin.readline().split()]\nm = numbers[0]\nn = numbers[1]\nprint(int(m * n / 2))\n","a = list(map(int, input().split()))\nproduct = 1\nfor i in range(len(a)):\n\tproduct *= a[i]\nans = product // 2\nprint(ans)\n","s = input().split()\na = int(s[0])\nb = int(s[1])\nprint(int(a * b * 0.5))\n","(m, n) = map(int, input().split())\narea = m * n\nfitting = area // 2\nprint(fitting)\n","from math import *\n(m, n) = [int(i) for i in input().split()]\ndominos = m * n // (2 * 1)\nprint(dominos)\n","(x, y) = map(int, input().split())\np = x * y\nmax_num = p // 2\nprint(max_num)\n","lst = input().split(' ')\ns = int(lst[0]) * int(lst[1])\nif s % 2:\n\tprint((s - 1) // 2)\nelse:\n\tprint(s // 2)\n","x = 0\ny = 0\nz = 0\n(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nif m > n:\n\tif m % 2 == 0:\n\t\tx = m // 2\n\t\ty = n\n\t\tz = x * y\n\telif n % 2 == 0:\n\t\tx = n // 2\n\t\ty = m\n\t\tz = x * y\n\telse:\n\t\tx = m // 2 * n\n\t\ty = n // 2\n\t\tz = x + y\nelif n > m:\n\tif n % 2 == 0:\n\t\tx = n // 2\n\t\ty = m\n\t\tz = x * y\n\telif m % 2 == 0:\n\t\tx = m // 2\n\t\ty = n\n\t\tz = x * y\n\telse:\n\t\tx = n // 2 * m\n\t\ty = m // 2\n\t\tz = x + y\nelif m == n:\n\tif n % 2 == 0:\n\t\tx = n // 2\n\t\ty = m\n\t\tz = x * y\n\telse:\n\t\tx = n // 2\n\t\ty = m // 2\n\t\tz = x * m + y\nprint(z)\n","def solution(m, n):\n\tcount = 0\n\twhile True:\n\t\tif m >= 2:\n\t\t\ts = m // 2\n\t\t\tm = m - s * 2\n\t\t\tcount = count + n * s\n\t\tif n >= 2:\n\t\t\ts = n // 2\n\t\t\tn = n - s * 2\n\t\t\tcount = count + m * s\n\t\tif n <= 1 and m <= 1:\n\t\t\tbreak\n\treturn count\n\ndef main():\n\t(m, n) = map(int, input().split())\n\tans = solution(m, n)\n\tprint(ans)\nmain()\n","data = input()\ndata = data.split(' ')\ns = int(data[0]) * int(data[1])\nresult = s // 2\nprint(result)\n","dominoarea = 2\n(linha, coluna) = input().split()\nlinha = int(linha)\ncoluna = int(coluna)\narea = linha * coluna\ndominos = area // dominoarea\nprint(dominos)\n","import math as M\n(m, n) = map(int, input().split())\nprint(M.floor(m * n / 2))\n","(M, N) = [int(x) for x in input().split()]\ns = M * N\nif s % 2 == 0:\n\tnum = s // 2\n\tprint(num)\nelse:\n\tnum = s // 2\n\tprint(num)\n","(M, N) = input().split()\nM1 = int(M)\nN1 = int(N)\nX = int(M1 * N1 * 0.5)\nprint(X)\n","def piling(m, n):\n\tGivenArea = m * n\n\tRequiredArea = 2 * 1\n\treturn GivenArea // RequiredArea\n(m, n) = map(int, input().split(' '))\nprint(piling(m, n))\n","mn = input().split(' ')\nm = int(mn[0])\nn = int(mn[1])\nrows = m // 2\nc = m % 2\nhorizontal_dominos = 0\nif c == 1:\n\thorizontal_dominos = n // 2\nvertical_dominos = rows * n\nprint(horizontal_dominos + vertical_dominos)\n","i = lambda : map(int, input().split())\n(x, y) = i()\nprint(x * y // 2)\n","(m, n) = map(int, input().split())\nprint(round(m * n / 2 - 0.2))\n","def main():\n\tfrom sys import stdin, stdout\n\t(n, m) = map(int, stdin.readline().split())\n\tstdout.write(str(n * m // 2))\nmain()\n","numbers = input()\n(a, b) = numbers.split(' ')\narea = int(a) * int(b)\nprint(area // 2)\n","def solve(m, n):\n\tdomino_pieces = 2 * 1\n\trectangular_board = m * n\n\treturn rectangular_board // domino_pieces\n(m, n) = map(int, input().split(' '))\nprint(solve(m, n))\n","dimensions = input('')\n(m, n) = dimensions.split(' ')\namt = int(m) * int(n) // 2\nprint(amt)\n","(M, N) = input().split()\ndomino = int(M) * int(N) // 2\nprint(domino)\n","(m, n) = map(int, input().split())\nt = 0\nfor d in range(m * n):\n\tif m * n % 2 == 0:\n\t\tif m * n > 2 * d:\n\t\t\tt += 1\n\t\t\tfinal = t\n\t\telse:\n\t\t\tbreak\n\telif m * n > 2 * d:\n\t\tt += 1\n\t\tfinal = t - 1\n\telse:\n\t\tbreak\nprint(final)\n","(n, m) = map(int, input().split())\nareaOfSquare = n * m\ntotal = areaOfSquare // 2\nprint(total)\n","(m, n) = map(int, input().split())\na = m * n\np = a // 2\nprint(p)\n","(m, n) = list(map(int, input().split(' ')))\n\ndef s(a):\n\tif a <= 1:\n\t\treturn 0\n\treturn a // 2 + s(a % 2)\nprint(s(m * n))\n","board_size = list(map(int, input().split()))\na = board_size[0]\nb = board_size[1]\ncount = 0\nboard = [[0 for i in range(b)] for j in range(a)]\nfor i in range(a):\n\tfor j in range(0, b, 2):\n\t\tif b - j >= 2 and (board[i][j] == 0 and board[i][j + 1] == 0):\n\t\t\tcount += 1\n\t\t\tboard[i][j] = board[i][j + 1] = 1\nfor j in range(b):\n\tfor i in range(0, a, 2):\n\t\tif a - i >= 2 and (board[i][j] == 0 and board[i + 1][j] == 0):\n\t\t\tcount += 1\n\t\t\tboard[i + 1][j] = board[i][j] = 1\nprint(count)\n","ip = input().split(' ')\nm = int(ip[0])\nn = int(ip[1])\nprint(int(m * n / 2))\n","(a, b) = input('').split()\ntotal = int(a) * int(b)\nif total % 2 == 0:\n\tmax = int(total / 2)\n\tprint(max)\nelse:\n\tmax = int((total - 1) / 2)\n\tprint(max)\n","def Domino(m, n):\n\treturn m * n // 2\n(x, y) = input().split()\nprint(Domino(int(x), int(y)))\n","(m, n) = list(map(int, input().split()))\nx = m * n\nprint(int(x / 2))\n","lst = list(map(int, input('\\n').strip().split()))[:2]\nprint(lst[0] * lst[1] // 2)\n","import math\nboard_size = input().split(' ')\nprint(math.trunc(int(board_size[0]) * int(board_size[1]) / 2))\n","dim = [int(s) for s in input().split()]\nsize = dim[0] * dim[1]\nif size % 2 != 0:\n\tprint((size - 1) // 2)\nelse:\n\tprint(size // 2)\n","arr = list(map(int, input().split(' ')))\nn = arr[0]\nm = arr[1]\narea = n * m\nprint(int(area / 2))\n","import math\n(x, y) = input().split()\nx = int(x)\ny = int(y)\nz = x * y\na = math.floor(z / 2)\nprint(a)\n","(n, m) = input().split(' ')\n(n, m) = (int(n), int(m))\nsum = n * (m // 2)\nif m % 2 == 1:\n\tsum += n // 2\nprint(sum)\n","b = []\nb1 = input()\nb2 = b1.split()\nfor k in b2:\n\tb.append(int(k))\nS = b[1] * b[0]\nprint(S // 2)\n","lines = input().split()\nlines = list(map(int, lines))\n(x, y) = (lines[0], lines[1])\nprint(int(x * y / 2))\n","(a, b) = map(int, input().split(' '))\nif a % 2 == 1:\n\tc = int(a / 2)\n\td = b * c + int(b / 2)\nelse:\n\td = int(b * a / 2)\nprint(d)\n","(m, n) = list(map(int, input().strip().split()))\narea = m * n\ndomino = area // 2\nprint(domino)\n","(M, N) = list(map(int, input().strip().split(' ')))\nif M % 2 != 0 and N % 2 != 0:\n\tans = (M * N - 1) / 2\nelse:\n\tans = M * N / 2\nprint(int(ans))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m < n:\n\t(m, n) = (n, m)\nx = m // 2\ny = n // 1\nneed = x * y\nif m % 2 == 1 and n != 1:\n\tneed += n // 2\nprint(need)\n","(m, n) = [int(x) for x in input().split(' ')]\nside = m // 2\nret = side * n\nif side * 2 != m:\n\tret += n // 2\nprint(ret)\n","(n, m) = [int(i) for i in input().split()]\ny = m * n // 2\nprint(y)\n","m = input()\nls = []\nls = m.split(' ')\nm = int(ls[0])\nn = int(ls[1])\nprod = m * n\nans = prod // 2\nprint(ans)\n","def main():\n\t(x, y) = input().split()\n\tx = int(x)\n\ty = int(y)\n\tz = x * y\n\tz = z // 2\n\tprint(z)\nmain()\n","def DominoPiling():\n\t(m, n) = map(int, input().split(' '))\n\tif m % 2 == 0 or n % 2 == 0:\n\t\tprint(m * n // 2)\n\telif m == 1 or n == 1:\n\t\tprint(max(m, n) // 2)\n\telse:\n\t\tprint(min(m, n) // 2 * max(m, n) + max(m, n) // 2)\n\treturn None\n\ndef main():\n\tDominoPiling()\nmain()\n","l = list(map(int, input().rstrip().split()))\ntot = l[0] * l[1]\nprint(tot // 2)\n","z = str(input()).split()\ncount = int(z[0]) * int(z[1])\nprint(count // 2)\n","(n, m) = map(int, input().split(' '))\np = m * n\nk = p // 2\nprint(k)\n","(M, N) = input('').split()\n(M, N) = (int(M), int(N))\nmaximum = M * N // 2\nprint(maximum)\n","(n, m) = list(map(int, input().split()))\nc = 0\nif 1 <= m <= 16 and 1 <= n <= 16:\n\twhile True:\n\t\tif n >= 2:\n\t\t\tn -= 2\n\t\t\tc += m\n\t\tif n == 1:\n\t\t\tn -= 1\n\t\t\tc += int(m / 2)\n\t\tif n == 0:\n\t\t\tbreak\nprint(c)\n","(m, n) = map(int, input().split())\narea = m * n\nnum_ds = 0\nif area == 1:\n\tprint('0')\nelse:\n\tfor i in range(1, area, 2):\n\t\tnum_ds += 1\n\tprint(num_ds)\n","mn = input()\nmn = mn.split()\nfor i in range(2):\n\tmn[i] = int(mn[i])\nsquares = mn[0] * mn[1]\nprint(squares // 2)\n","(m, n) = map(int, input().split())\nb = m // 2\ninitial = b * n\nremb = m - 2 * b\nfinalvalue = initial\nif remb == 1:\n\tl = n // 2\n\tfinalvalue += l\nprint(finalvalue)\n","import math\nn = [int(x) for x in input().split()]\nr = math.floor(n[0] * n[1] / 2)\nprint(r)\n","a = input().split()\na = list(map(int, a))\nS = a[0] * a[1]\nnum = S // 2\nprint(num)\n","n = str(input()).split()\nmn = int(n[0]) * int(n[1])\nprint(mn // 2)\n","x = input()\ny = x.split(' ')\nz = int(y[0])\nk = int(y[1])\ntablero = z * k\nif tablero % 2 == 0:\n\tprint(int(tablero / 2))\nelse:\n\tprint(int((tablero - 1) / 2))\n","def noOfDominos(n, m):\n\tif n % 2 == 0:\n\t\treturn n // 2 * m\n\telse:\n\t\treturn n // 2 * m + m // 2\n(n, m) = [int(x) for x in input().split()]\nprint(noOfDominos(n, m))\n","import sys\nsides = sys.stdin.readline().rstrip('\\n').split(' ')\nsides = [int(i) for i in sides]\narea = sides[0] * sides[1]\nprint(area // 2)\n","s = str(input())\nm = n = str()\nk = i = 0\nfor i in range(len(s)):\n\tif s[i] != ' ':\n\t\tm += s[i]\n\telse:\n\t\tk = i + 1\n\t\tbreak\nwhile k != len(s):\n\tn += s[k]\n\tk += 1\nm = int(m)\nn = int(n)\na = int(m * n * 0.5)\nprint(a)\n","def dominos(length, width):\n\tarea = length * width\n\tdomino = area // 2\n\treturn domino\n\ndef main():\n\tinp = input()\n\ttemp = inp.split(' ')\n\tlength = int(temp[0])\n\twidth = int(temp[1])\n\tprint(dominos(length, width))\nmain()\n","def main():\n\tmn = input()\n\tmn = mn.split(' ')\n\tarea = int(int(mn[0]) * int(mn[1]) / 2)\n\tprint(area)\nmain()\n","(m, n) = (int(i) for i in input().split())\nmd = m // 2\nmr = m % 2\nprint(md * n + mr * n // 2)\n","from math import ceil\n(a, b) = map(int, input().split())\nif a < b:\n\t(a, b) = (b, a)\nbase = a * (b // 2)\nif b % 2 != 0:\n\tbase += a // 2\nprint(base)\n","def main():\n\t(m, n) = map(int, input().split())\n\tboard = [[0 for _ in range(n)] for _ in range(m)]\n\tcount = 0\n\tfor i in range(m):\n\t\tfor j in range(n - 1):\n\t\t\tif board[i][j] == board[i][j + 1] == 0:\n\t\t\t\t(board[i][j], board[i][j + 1]) = (1, 1)\n\t\t\t\tcount += 1\n\t\tif i + 1 < m and board[i][n - 1] == 0:\n\t\t\t(board[i][n - 1], board[i + 1][n - 1]) = (1, 1)\n\t\t\tcount += 1\n\tprint(count)\nmain()\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\narea = m * n\ncount = math.floor(area / 2)\nprint(count)\n","a = input()\nx = int(a[0:2])\ny = int(a[2:5])\nb = x * y\nprint(b // 2)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nm = M * N\nr = m / 2\nr = int(r)\nprint(r)\n","(a, b) = [int(x) for x in input().split()]\nc = 2\nres = a * b // 2\nprint(res)\n","mn_string = input()\nmn_list = mn_string.split(' ')\nsquares = int(mn_list[0]) * int(mn_list[1])\nsolution = squares // 2\nprint(solution)\n","rd = lambda : list(map(int, input().split()))\n(m, n) = rd()\nprint(n * m // 2)\n","[m, n] = [int(x) for x in input().split(' ')]\nprint(f'{m * n // 2}')\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nres = a // 2 * b\nif a % 2 == 1:\n\tres += b // 2\nprint(res)\n","t = input()\ni = 0\nsum = 1\nformated = t.split(' ')\nwhile i <= len(formated) - 1:\n\tsum = sum * int(formated[i])\n\ti += 1\nprint(sum // 2)\n","import sys\nlines = list(sys.stdin)\na = int(lines[0].split()[0])\nb = int(lines[0].split()[1])\nprint(a * b // 2)\n","l = [int(e) for e in input().split()]\nprint(l[0] * l[1] // 2)\n","__author__ = 'zhangxun'\n\ndef main():\n\tm_n_scale = input()\n\tm = int(m_n_scale.split(' ')[0])\n\tn = int(m_n_scale.split(' ')[1])\n\tcouter = 0\n\tif m == 1:\n\t\tcouter += n // 2\n\telif m >= 2 and m % 2 == 0:\n\t\tcouter += m // 2 * n\n\telse:\n\t\tcouter += m // 2 * n\n\t\tcouter += n // 2\n\tprint(couter)\nmain()\n","(m, n) = map(int, input().split())\n1 <= m <= n <= 16\nimport math\nnum = math.floor(m * n / 2)\nprint(num)\n","s = list(map(int, input().split(' ')))\nans = -1\nif s[0] % 2 == 0:\n\tif s[1] % 2 == 0:\n\t\tans = s[0] * s[1] / 2\n\telse:\n\t\tans = s[0] * (s[1] - 1) / 2 + s[0] / 2\nelif s[1] % 2 == 0:\n\tans = s[1] * (s[0] - 1) / 2 + s[1] / 2\nelse:\n\tans = (s[0] - 1) * (s[1] - 1) / 2 + (s[0] - 1) / 2 + (s[1] - 1) / 2\nprint(int(ans))\n","(a, b) = map(int, input().strip().split())\n\ndef sol(m, n):\n\tif m % 2 == 0:\n\t\treturn m // 2 * n\n\telif n % 2 == 0:\n\t\treturn n // 2 * m\n\telse:\n\t\treturn m // 2 * n + n // 2\nprint(sol(a, b))\n","s = input()\nm = 0\nn = 0\nfor i in range(len(s)):\n\tif s[i] == ' ':\n\t\tn = m\n\t\tm = 0\n\telse:\n\t\tm = m * 10 + int(s[i])\nprint(n * m // 2)\n","(m, n) = map(int, input().split())\n\ndef solve(m, n):\n\ttotal = 0\n\treturn m * n / 2\nprint(int(solve(m, n)))\n","(N, M) = map(int, input().split())\nimport math\nprint(math.trunc(N * M / 2))\n","a = input().split()\nindex = int(a[0]) * int(a[1]) // 2\nprint(index)\n","(m, n) = map(int, input().split())\nif m % 2 == 0 or n % 2 == 0:\n\tmax_domino = m * n / 2\nelse:\n\tmax_domino = m // 2 * n + n // 2\nprint(int(max_domino))\n","def solution() -> int:\n\t(m, n) = map(int, input().split())\n\ts = m * n\n\tcnt = 0\n\twhile not s <= 1:\n\t\tcnt += 1\n\t\ts -= 2\n\treturn cnt\nprint(solution())\n","def solve():\n\t(M, N) = map(int, input().split())\n\tprint(M * N // 2)\nTestcase = 1\nfor _ in range(Testcase):\n\tsolve()\n","import math\n(n, m) = map(int, input().split())\nl = 2\nb = 1\nx = n / l\ny = m / b\nprint(math.floor(x * y))\n","inp = input().split()\nm = int(inp[0])\nn = int(inp[1])\nout = m * n // 2\nprint(out)\n","(m, n) = map(int, input().split())\narea = m * n\ndominos = area // 2\nprint(dominos)\n","(m, n) = input().split()\nboard_size = int(m) * int(n)\nif int(m) > int(n) or int(n) > 16:\n\tprint('Error')\nelif int(m) * int() % 2 == 0:\n\tprint(int(m) * int(n) // 2)\nelif int(m) * int(n) % 2 == 1:\n\tprint(int(m) * int(n) // 2)\n","(l, b) = input().split()\nl = int(l)\nb = int(b)\nrem = 0\ncount = 0\nfor i in range(l):\n\tif b % 2 == 0:\n\t\tcount += int(b / 2)\n\telse:\n\t\tcount += int(b / 2)\n\t\trem += 1\ncount += int(rem / 2)\nprint(count)\n","def main():\n\ta = input().split(' ')\n\tl = int(a[0])\n\tw = int(a[1])\n\tl1 = l // 2\n\tn = l1 * w + l % 2 * w // 2\n\tprint(n)\nmain()\n","inp = input().split()\nprint(int(eval(inp[0]) * eval(inp[1]) / 2))\n","a = list(map(int, input().strip().split(' ')))\nans = a[0] * a[1]\nans = ans // 2\nprint(ans)\n","a = [int(x) for x in input().split()]\nif a[0] < a[1]:\n\ttemp = a[0]\n\ta[0] = a[1]\n\ta[1] = temp\nres = a[0] // 2 * a[1] + a[0] % 2 * a[1] // 2\nprint(res)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nz = m * n\ny = z / 2\ny = int(y)\nif 1 <= m <= n <= 16:\n\tprint(y)\nelse:\n\tprint('invalid value')\n","(M, N) = [int(x) for x in input('').split()]\nboard_area = M * N\ndomino_area = 2\nprint(board_area // domino_area)\n","from math import ceil\n(m, n) = map(int, input().split())\nif m % 2 == 0 or n % 2 == 0:\n\tprint(m * n // 2)\nelse:\n\tprint(max(ceil(m * n / 2) - 1, 0))\n","import sys, bisect, copyreg, copy, statistics, os\n\ndef inp():\n\treturn sys.stdin.readline().strip()\n\ndef IIX():\n\treturn (int(x) for x in sys.stdin.readline().split())\n\ndef II():\n\treturn int(inp())\n\ndef LI():\n\treturn list(map(int, inp().split()))\n\ndef L(x):\n\treturn list(x)\n\ndef out(var):\n\treturn sys.stdout.write(str(var))\n(m, n) = IIX()\narea = m * n\ndominoes = area // 2\nout(dominoes)\n","(n1, n2) = map(int, input().split())\nsq = n1 * n2\ndo = sq // 2\nprint(do)\n","(uzndk, eny) = map(int, input().split())\nnmbr_of_dmns = 0\nif uzndk % 2 == 0:\n\tnmbr_of_dmns = uzndk / 2 * eny\nelif eny % 2 == 0:\n\tnmbr_of_dmns = eny // 2 * uzndk\nelse:\n\tnmbr_of_dmns = uzndk // 2 * eny + eny // 2\nprint(int(nmbr_of_dmns))\n","(m, n) = map(int, input().split())\nBoard = m * n\nPieces = 2 * 1\nnumber = int(Board / Pieces)\nprint(number)\n","x = input().split()\ny = 0\nif x[0] > x[1]:\n\ttool = int(x[0])\n\tarz = int(x[1])\nelse:\n\ttool = int(x[1])\n\tarz = int(x[0])\nif tool >= 2 and arz >= 1:\n\ty = y + tool // 2 * arz // 1\n\tif tool % 2 == 1 and arz >= 2:\n\t\ty = y + arz // 2\nprint(y)\n","data = input('')\nm = data.find(' ')\nM = int(data[:m])\nN = int(data[m + 1:])\na = 2\nb = 1\ndom = int(M * N / (a * b))\nprint(dom)\n","import math\n(n, m) = map(int, input().split())\nz = 0\nif n == 1 and m == 1:\n\tprint(0)\n\texit()\nif n % 2 == 0:\n\tz = m * math.floor(n / 2)\nelif m % 2 == 0:\n\tz = n * math.floor(m / 2)\nelif n > m:\n\tz = m * math.floor(n / 2) + math.floor(m / 2)\nelse:\n\tz = n * math.floor(m / 2) + math.floor(n / 2)\nprint(z)\n","from sys import stdin, stdout\n(n, m) = [int(y) for y in stdin.readline().split()]\nprint(int(n * m * 0.5))\n","N = list(map(int, input().split()))\nprint(N[0] * N[1] // 2)\n","from collections import Counter\nimport math\nimport sys\nfrom bisect import bisect, bisect_left, bisect_right\n\ndef input():\n\treturn sys.stdin.readline().strip()\n\ndef INT():\n\treturn int(input())\n\ndef MAP():\n\treturn map(int, input().split())\n\ndef LIST(N=None):\n\treturn list(MAP()) if N is None else [INT() for i in range(N)]\n\ndef mod():\n\treturn 10 ** 9 + 7\n(n, k) = MAP()\nans = 0\nprint(math.floor(n * k / 2))\n","x = input().split()\nm = int(x[0])\nn = int(x[1])\narea = m * n\nif m % 2 == 0 or n % 2 == 0:\n\tevenAns = area / 2\n\tprint(int(evenAns))\nelse:\n\toddAns = (area - 1) / 2\n\tprint(int(oddAns))\n","(a, b) = map(int, input().strip().split())\nprint(max(b * (a // 2) + b // 2 * (a % 2), a * (b // 2) + a // 2 * (b % 2)))\n","(m, n) = [int(x) for x in input().strip().split()]\nprint(int(m * n // 2))\n","(l, b) = map(int, input().split(' '))\na = 2\nprint(l * b // a)\n","(n, m) = map(int, input().split())\ns = n * m\nsq = 2\ndom = 0\nif s % sq == 0:\n\tdom = s // sq\nelse:\n\tdom = s // sq\nprint(dom)\n","import math\nN = input()\na = N.split()\nm = int(a[0])\nn = int(a[1])\nq = m % 2\nw = math.floor(m / 2)\nif q == 0:\n\tx = w * n\nelse:\n\tx = w * n + math.floor(n / 2)\nprint(x)\n","(m, n) = input().split()\n(m, n) = [int(m), int(n)]\not = m / 2 * n\not = int(ot)\nprint(ot)\n","import math\nsize = input()\n(x, y) = size.split()\nx = int(x)\ny = int(y)\ndominoes = 0\noffset = 0\nif x > 1:\n\tif not x % 2 == 0:\n\t\toffset = 1\n\tdominoes += math.floor((x - offset) / 2 * y)\nif x == 1 or (offset == 1 and y > 1):\n\tdominoes += math.floor(y / 2)\nprint(dominoes)\n","l = list(map(int, input().split()))\nM = max(l[0], l[1])\nN = min(l[0], l[1])\nx = M // 2 * N + M % 2 * (N // 2)\nprint(x)\n","def calc_dominee(m, n):\n\tif m <= 0 or n <= 0:\n\t\treturn 0\n\tif m == 1:\n\t\treturn n // 2\n\tif n == 1:\n\t\treturn m // 2\n\tif m >= n and n >= 2:\n\t\treturn m + calc_dominee(m, n - 2)\n\telse:\n\t\treturn n + calc_dominee(m - 2, n)\n(M, N) = map(int, input().split())\nprint(calc_dominee(M, N))\n","(a, b) = map(int, input().split())\nc = b\nif a > b:\n\tb = a\n\ta = c\nmain_a = a\nif a % 2 == 0:\n\tno_dom = int(a / 2 * b)\nelse:\n\ta -= 1\n\tno_dom = int(a / 2 * b)\nif main_a % 2 != 0 and b % 2 == 0:\n\tno_dom += int(b / 2)\nelif main_a % 2 != 0 and b % 2 != 0:\n\tno_dom += int((b - 1) / 2)\nprint(no_dom)\n","(X, Y) = map(int, input().split())\n(A, B) = (min(X, Y), max(X, Y))\nprint(A // 2 * B + A % 2 * (B // 2))\n","(m, n) = input().split()\nmul = int(m) * int(n)\nd = mul // 2\nif m == 1 and n == 1:\n\tprint(0)\nelse:\n\tprint(d)\n","temp = input().strip().split()\nm = int(temp[0])\nn = int(temp[1])\nq = m * n // 2\nprint(q)\n","import math\nBord = input().split(' ')\nOppervlakte = 0\nOppervlakte = int(Bord[0]) * int(Bord[1])\nprint(math.trunc(Oppervlakte / 2))\n","inp = input()\nli = list(map(int, inp.split()))\nm = li[0] * li[1]\ni = 0\nsu = 0\nif li[0] == 0 or li[1] == 0:\n\tsu = 0\nelif li[0] > 0 and li[1] > 0:\n\twhile i >= 0:\n\t\tsu = su + 2\n\t\tif su > m:\n\t\t\tsu = su - 2\n\t\t\tbreak\n\t\ti = i + 1\nprint(round(su / 2))\n","line = input()\na = [int(i) for i in line.split()]\nprint(a[1] * a[0] // 2)\n","import math as mp\n(n, m) = map(int, input().split())\nt = mp.floor(n * m * 0.5)\nprint(int(t))\n","(m, n) = list(map(int, input().split()))\ndominoes = 0\nsqr_covered = 0\nsqr_extra = 0\nfor x in range(m):\n\tfor y in range(n):\n\t\tsqr_covered += 1\n\t\tif sqr_covered % 2 == 0:\n\t\t\tdominoes += 1\nprint(dominoes)\n","def fun(N):\n\ts = N[0] * N[1]\n\tresult = s // 2\n\treturn result\nN = list(map(int, input().split()))\nprint(fun(N))\n","board_sizes = list(map(int, input().split()))\nfirstElement = int(board_sizes[0])\nsecondElement = int(board_sizes[-1])\nresult = firstElement * secondElement // (2 * 1)\nprint(result)\n","import math\n(rows, col) = map(int, input().split())\nprint(math.floor(rows * col * 0.5))\n","nk = list(map(int, input().split()))\nris = nk[0] * nk[1]\nris -= ris % 2\nprint(ris // 2)\n","i = list(map(int, input().split()))\np = i[0]\nq = i[1]\nM = ['w' for i in range(p) for j in range(q)]\nm = len(M) // 2\nprint(m)\n","import sys\n\ndef domino(m, n):\n\tprint(m * n // 2)\ns = sys.stdin.readline().strip('/n')\ns = ' '.join(s.split())\nx = s.split(' ')\nif int(x[0]) <= int(x[1]) and int(x[0]) >= 1 and (int(x[1]) <= 16):\n\tdomino(int(x[0]), int(x[1]))\n","(a, b) = map(int, input().strip().split())\nw = a * b / 2\nprint(int(w))\n","(m, n) = map(int, input().split())\nt = m * n\nsum = t // 2\nprint('{0}'.format(sum))\n","line = input()\npieces = line.split()\na = int(pieces[0])\nb = int(pieces[1])\nc = a * b\nd = int(c / 2)\nprint(d)\n","(a, b) = map(int, input().split())\noutput = a * b // 2\nprint(output)\n","import math\n(M, N) = map(int, input().split())\nd = int(M * N / 2)\nprint(d)\n","(m, n) = map(int, input().split())\nsize_board = m * n\nsize_pieces = 2\nmax_num = size_board // size_pieces\nprint(max_num)\n","import math\ninp = input()\nnumbers = [int(s) for s in inp.strip().split(' ')]\nm = numbers[0]\nn = numbers[1]\nif n % 2 != 0:\n\tprint(math.floor(n / 2) * m + math.floor(m / 2))\nelse:\n\tprint(math.floor(n / 2) * m)\n","import math\n(a, b) = map(int, input().split())\nad = 1\nbd = 2\na = a * b / (ad * bd)\na = math.floor(a)\nprint(a)\n","nm = input().split()\narea = int(nm[0]) * int(nm[1])\nprint(int(area / 2))\n","(n, k) = input().split()\nn = int(n)\nk = int(k)\nif k * n % 2 == 0:\n\tans = int(k * n / 2)\nelse:\n\tans = int((k * n - 1) / 2)\nprint(ans)\n","dapigu = str(input())\ndapigu = dapigu.split(' ')\nM = int(dapigu[0])\nN = int(dapigu[1])\nm = M // 2\nn = M % 2\nif n != 0:\n\tprint(str(m * N + N // 2))\nelse:\n\tprint(str(m * N))\n","a = input().split(' ')\nx = int(a[0]) * int(a[1])\nif x % 2 == 0:\n\tprint(int(x / 2))\nelse:\n\tprint(int((x - 1) / 2))\n","inp = input()\nx = inp.split()\na = int(x[0]) * int(x[1])\nx = a % 2\nif x == 1:\n\ta = a - 1\n\tprint(int(a / 2))\nelif x == 0:\n\tprint(int(a / 2))\n","(m, n) = input().split()\nr = eval(m) * eval(n) // 2\nprint(r)\n","rect = list(map(int, input().split()))\narea = rect[0] * rect[1]\nprint(int((area - area % 2) / 2))\n","n = list(map(int, input().split()))\ncross = n[0] * n[1]\nresult = cross // 2\nprint(result)\n","(m1, n) = map(int, input().split())\nprint(m1 * n // 2)\n","(p, q) = list(map(int, input().split()))\nr = p * q\nif r % 2 == 0:\n\te = r // 2\n\tprint(e)\nelse:\n\to = (r - 1) // 2\n\tprint(o)\n","def prob50a(m, n):\n\tlength = n // 2\n\textrapcs = 0\n\tif n % 2 == 1:\n\t\textrapcs = m // 2\n\treturn length * m + extrapcs\n(m, n) = map(int, input().split(' '))\nresult = prob50a(m, n)\nprint(result)\n","square = list(map(int, input().split()))\nanswer = max(square) // 2 * min(square) + max(square) % 2 * (min(square) // 2)\nprint(answer)\n","s = input()\nli = s.split()\nm = int(li[0]) * int(li[1])\nprint(m // 2)\n","t = input()\nt_holder = ''\nfor item in t:\n\tif item == ' ':\n\t\tm = int(t_holder)\n\t\tt_holder = ''\n\telse:\n\t\tt_holder += item\nn = int(t_holder)\nprint(n * m // 2)\n","import math\nlst = list(map(int, input().split()))\n(M, N) = [lst[i] for i in range(0, 2)]\nboardsquare = M * N\ndomino = 2 * 1\n1 <= M <= N <= 16\ntotal = math.floor(boardsquare / domino)\nprint(total)\n","n = list(map(int, input().split()))\nx = n[0]\ny = n[1]\nif x % 2 != 0 and y % 2 != 0:\n\ta = x * y - 1\n\tb = a / 2\n\tprint(int(b))\nelse:\n\tprint(int(x * y * 0.5))\n","ip = str(input()).split(' ')\nm = int(ip[0])\nn = int(ip[1])\nnum_of_dominos_placed = 0\n\ndef print_board():\n\tglobal board\n\tfor row in board:\n\t\tprint(''.join(row))\n\ndef place_domino(row, col):\n\tglobal board, num_of_dominos_placed, m, n\n\tif board[row][col] == '*':\n\t\tif col + 1 < n and board[row][col + 1] == '*':\n\t\t\tboard[row][col] = '-'\n\t\t\tboard[row][col + 1] = '-'\n\t\t\tnum_of_dominos_placed += 1\n\t\telif row + 1 < m and board[row + 1][col] == '*':\n\t\t\tboard[row][col] = '|'\n\t\t\tboard[row + 1][col] = '|'\n\t\t\tnum_of_dominos_placed += 1\nboard = []\nfor row in range(m):\n\tboard.append(['*' for col in range(n)])\nfor row in range(m):\n\tfor col in range(n):\n\t\tplace_domino(row, col)\nprint(num_of_dominos_placed)\n","import math\n\ndef domino():\n\tn = input().split()\n\tarea = int(n[0]) * int(n[1])\n\ttotalFilled = math.floor(area / 2)\n\tprint(totalFilled)\ndomino()\n","while True:\n\tsize = input()\n\tdimensions = size.split(' ')\n\ttry:\n\t\tlength = int(dimensions[0])\n\t\twidth = int(dimensions[1])\n\texcept ValueError:\n\t\tpass\n\telse:\n\t\tbreak\narea = length * width\ndominoes = int(area / 2 - area % 2 / 2)\nprint(dominoes)\n","def mul(a):\n\tb = 1\n\tfor i in range(len(a)):\n\t\tb *= a[i]\n\treturn b\na = [int(x) for x in input().split()]\nprint(mul(a) // 2)\n","l = list()\nwhile True:\n\tboard = input()\n\tl = board.split(' ')\n\tM = int(l[0])\n\tN = int(l[1])\n\tif 1 <= M <= N <= 16:\n\t\tbreak\nprint(M * N // 2)\n","data_input = input()\ndata_input = data_input.split(' ')\nn = int(data_input[0])\nm = int(data_input[1])\nsqrt = n * m\nres = 0\nwhile sqrt - 2 >= 0:\n\tres += 1\n\tsqrt -= 2\nif sqrt < 0:\n\tres -= 1\nprint(res)\n","(m, n) = map(int, input().split())\narea = m * n\ns = int(area / 2)\nprint(s)\n","import sys\ns = input()\ns = s.split(' ')\ns1 = int(s[0])\ns2 = int(s[1])\nboard = s1 * s2\nans = board // 2\nprint(ans)\n","from sys import stdin\n\ndef main():\n\t(m, n) = [int(i) for i in stdin.readline().strip().split()]\n\tprint(int(m / 2 * n))\nmain()\n","prompt = input().split(' ')\nprint(int(prompt[0]) * int(prompt[1]) // 2)\n","(a, b) = map(int, input().split())\nif a % 2 == 0:\n\tprint(b * (a // 2))\nif b % 2 == 0 and a % 2 != 0:\n\tprint(a * (b // 2))\nif a % 2 != 0 and b % 2 != 0:\n\tp = max(a, b)\n\tc = p // 2 * min(a, b) + min(a, b) // 2\n\tprint(c)\n","ent = input()\nentrada = ent.split(' ')\nmult = int(entrada[0]) * int(entrada[1])\nprint(mult // 2)\n","l = list(map(int, input().strip().split()))\nn = l[0]\nm = l[1]\narea = n * m\nif area % 2 == 0:\n\tans = int(area / 2)\n\tprint(ans)\nelse:\n\tans = int((area - 1) / 2)\n\tprint(ans)\n","import math\n(m, n) = map(int, input().split())\nresult = 0\nwhile m > 0:\n\tresult += n if m > 1 else math.floor(n / 2)\n\tm -= 2\nprint(result)\n","(m, n) = map(int, input().split())\nli = [[0 for _ in range(n)] for _ in range(m)]\nc = 0\nfor i in range(m):\n\tfor j in range(n):\n\t\tif j + 1 < n:\n\t\t\tif li[i][j] == 0 and li[i][j + 1] == 0:\n\t\t\t\tli[i][j] = 1\n\t\t\t\tli[i][j + 1] = 1\n\t\t\t\tc += 1\n\t\t\t\tj = j + 2\nfor i in range(n):\n\tfor j in range(m):\n\t\tif j + 1 < m:\n\t\t\tif li[j][i] == 0 and li[j + 1][i] == 0:\n\t\t\t\tli[j][i] = 1\n\t\t\t\tli[j + 1][i] = 1\n\t\t\t\tc += 1\n\t\t\t\tj = j + 2\nprint(c)\n","def main():\n\tlst = input().split()\n\tfor i in range(len(lst)):\n\t\tlst[i] = int(lst[i])\n\tif lst[0] <= 1 and lst[1] <= 1:\n\t\tprint(0)\n\telif lst[0] == 2:\n\t\tprint(lst[1])\n\telif lst[1] == 2:\n\t\tprint(lst[0])\n\telse:\n\t\tprint(int(lst[0] * lst[1] / 2))\nmain()\n","dimension = list(map(int, input().split(' ')))\nprint(dimension[0] * dimension[1] // 2)\n","import math\n(m, n) = input().split()\nvalue = math.floor(int(m) * int(n) / 2)\nprint(value)\n","(m, n) = map(int, input().split())\ns = m * n\nif s % 2 == 0:\n\ta = s // 2\n\tprint(a)\nelif s % 2 == 1:\n\tb = s // 2\n\tprint(b)\n","(m1, n1) = input().split()\nM = int(m1)\nN = int(n1)\ntotal = 0\nif M >= 2:\n\tif M / 2 == int(M / 2):\n\t\ttotal += int(M / 2 * N)\n\telif N / 2 == int(N / 2):\n\t\ttotal += int(int(M / 2) * N + N / 2)\n\telse:\n\t\ttotal += int(int(M / 2) * N + int(N / 2))\nelse:\n\ttotal += int(N / 2)\nprint(total)\n","g = input()\nfor i in range(len(g)):\n\tif g[i] == ' ':\n\t\tarea = int(g[:i]) * int(g[i + 1:])\n\t\tbreak\nprint(area // 2)\n","(n, m) = list(map(int, input().split()))\nmat = n * m\nprint(int(mat / 2))\n","(m, n) = (int(s) for s in input().split(' '))\nres = m * n // 2\nprint(res)\n","import math\nboard = str(input()).split()\nM = int(board[0])\nN = int(board[1])\na = min(M, N)\nb = max(M, N)\nnum = 0\nwhile a > 1:\n\tnum = b * math.floor(a / 2)\n\ta = a - 2 * math.floor(a / 2)\nwhile a == 1:\n\tnum = num + math.floor(b / 2)\n\ta = 0\nwhile a == 0:\n\tprint(num)\n\tbreak\n","(x, y) = map(int, input().split())\ns = x * y\nprint(int(s / 2))\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nif M % 2 == 0 or N % 2 == 0:\n\tprint(M * N // 2)\nelse:\n\tans = max((N - 1) * M // 2 + M // 2, (M - 1) * N // 2 + N // 2)\n\tprint(ans)\n","(M, N) = map(int, input().rstrip().split())\nif M == 1:\n\tif N == 1:\n\t\tprint(0)\n\telse:\n\t\tprint(N // 2)\nelse:\n\tdominoes = M // 2 * N + (0 if not M % 2 else N // 2)\n\tprint(dominoes)\n","a = input()\ns = a.split()\nM = int(s[0])\nN = int(s[1])\nsquares = M * N\nprint(squares // 2)\n","(m, n) = map(int, input().split())\narea = m * n\nnumber = area // 2\nprint(number)\n","import math\n(m, n) = map(int, input().split())\nrect = m * n\nma = math.floor(rect / 2)\nprint(ma)\n","import math\n(m, n) = map(int, input().split())\narr = 0\narr_gg = 0\nif m * n % 2 == 0:\n\tarr = m * n // 2\n\tprint(arr)\nif m * n % 2 != 0:\n\tarr_gg = math.floor(m * n / 2)\n\tprint(arr_gg)\n","s = list(map(int, input().split(' ')))\nM = s[0]\nN = s[1]\nsum = M * int(N / 2)\nif N % 2 == 1:\n\tsum = sum + int(M / 2)\nprint(sum)\n","(width, length) = map(int, input().split())\nresult = width * length / 2\nprint(int(result))\n","def fun():\n\t(a, b) = map(int, input().strip().split())\n\tif not b or not a:\n\t\tprint(0)\n\tc = a * b\n\td = c // 2\n\tprint(d)\nfun()\n","dimen = input()\ndimen = dimen.split()\nm = int(dimen[0])\nn = int(dimen[1])\narea = m * n\nprint(area // 2)\n","(n, m) = input().split()\n(n, m) = (int(n), int(m))\nC = n * m\nprint(C // 2)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif (m >= 1 and m <= 16) and (n >= 1 and n <= 16):\n\tarea = m * n\n\tprint(area // 2)\n","(m, n) = map(int, input().split())\nvalue = m * n\nresult = value // 2\nprint(result)\n","import sys\n(m, n) = [int(x) for x in sys.stdin.readline().split()]\nif m % 2 == 1 and n % 2 == 1:\n\tprint((m * n - 1) // 2)\nelse:\n\tprint(m * n // 2)\n","MN = input()\n(m, n) = MN.split()\nm = int(m)\nn = int(n)\nar = m * n\nar2 = 2\ncount = 0\nwhile ar2 <= ar:\n\tar2 += 2\n\tcount += 1\nprint(count)\n","input_str = input().split()\nres = int(input_str[0]) * int(input_str[1]) // 2\nprint(res)\n","import sys\n\ndef solve(m, n):\n\tif m * n % 2 == 0:\n\t\treturn m * n // 2\n\telse:\n\t\tx = 0\n\t\tif m == 1:\n\t\t\treturn n // 2\n\t\telif n == 1:\n\t\t\treturn m // 2\n\t\tif m % 2 != 0 and n % 2 != 0:\n\t\t\tif m < n:\n\t\t\t\tx = (m - 1) * n // 2\n\t\t\t\tx += n // 2\n\t\t\telse:\n\t\t\t\tx = (n - 1) * m // 2\n\t\t\t\tx += m // 2\n\t\t\treturn x\n\t\tif m % 2 != 0:\n\t\t\tx = (m - 1) * n // 2\n\t\t\tif m > n:\n\t\t\t\tx += m // 2\n\t\t\telse:\n\t\t\t\tx += n // 2\n\t\telse:\n\t\t\tx = (n - 1) * m // 2\n\t\t\tif m < n:\n\t\t\t\tx += n // 2\n\t\t\telse:\n\t\t\t\tx += m // 2\n\t\treturn x\nn = sys.stdin.readline()\nn = n.split(' ')\nprint(solve(int(n[0]), int(n[1])))\n","import math\n(m, n) = map(int, input().split(' '))\ns = 0\nif m % 2 == 0 or n % 2 == 0:\n\ts = n * m / 2\nelse:\n\ts = (m - 1) * n / 2 + math.floor(n / 2)\nprint(int(s))\n","(M, N) = [int(inputNum) for inputNum in input().split()]\nprint(int(M * N / 2))\n","import math\n(m, n) = map(int, input().split())\nans = m * n\nres = math.floor(ans / 2)\nprint(res)\n","x = input()\ny = x.split(' ')\na = []\nfor i in y:\n\ta.append(int(i))\nprint(a[0] * a[1] // 2)\n","inp = input().split()\nM = int(inp[0])\nN = int(inp[1])\nif M < 2 and N < 2:\n\tprint('0')\nelse:\n\tif M % 2 == 0 and M > 1:\n\t\t(am, bm) = (M, 0)\n\telse:\n\t\t(am, bm) = (M - 1, 1)\n\tif N % 2 == 0 and N > 1:\n\t\t(an, bn) = (N, 0)\n\telse:\n\t\t(an, bn) = (N - 1, 1)\n\tprint(int(am * an / 2 + bm * (an / 2) + bn * (am / 2)))\n","from sys import stdin, stdout\n(m, n) = tuple(map(int, stdin.readline().split()))\nquant = n * m // 2\nstdout.write(str(quant))\nexit(0)\n","temp = input().split(' ')\nlength = int(temp[0])\nheight = int(temp[1])\nhorizontal = int(length / 2)\nif length % 2 == 0:\n\tprint(horizontal * height)\nelse:\n\tvertical = int(height / 2)\n\tprint(horizontal * height + vertical)\n","x = [int(b) for b in input().split()]\nprint(x[0] * x[1] // 2)\n","w = input().split(' ')\nn = int(w[0])\nk = int(w[1])\nimport math\nprint(math.floor(n * k / 2))\n","(M, N) = [int(x) for x in input().split()]\nif 1 <= M <= 16 and 1 <= N <= 16:\n\tif M % 2 == 0 or N % 2 == 0:\n\t\tprint(round(M * N / 2))\n\telse:\n\t\tprint(round((M * N - 1) / 2))\n","dimensions = list(map(int, input().rstrip().rsplit()))\n(length, width) = (dimensions[0], dimensions[1])\nprint(int(length * width / 2))\n","(n, k) = map(int, input().split())\nprod = n * k\nif prod % 2 == 0:\n\tval = int(prod / 2)\n\tprint(val)\nelse:\n\tval = int((prod - 1) / 2)\n\tprint(val)\n","arr = list(map(int, input().split()))\nn = int(arr[0] * arr[1] / 2)\nprint(n)\n","inputLine = input()\ninputList = inputLine.split(' ')\nwidth = int(inputList[0])\nlength = int(inputList[1])\nprint(width * length // 2)\n","(a, b) = input().strip().split()\na = int(a)\nb = int(b)\nprint(a * b // 2)\n","marimi = input()\naria = int(marimi.split()[0]) * int(marimi.split()[1])\nprint(aria // 2)\n","import math\n(m, n) = input().split()\n(m, n) = (int(m), int(n))\nprint(math.floor(m * n / 2.0))\n","(a, b) = map(int, input().split())\n\ndef exa(a):\n\tx = int(a / 2)\n\ty = a - 2 * x\n\treturn (x, y)\n(a1, a2) = exa(a)\n(b1, b2) = exa(b)\nprint(2 * a1 * b1 + a2 * b1 + b2 * a1)\n","(m, n) = map(int, input().split())\nc = 0\na = [[0 for i in range(n)] for j in range(m)]\nfor i in range(m):\n\tc = c + a[i].count(0)\nprint(int(c // 2))\n","inv = input().rstrip()\nli = inv.split()\nli = list(map(int, li))\nar = li[0] * li[1]\nnum = int(ar / 2)\nprint(num)\n","import math\ndimension = input()\ndim = dimension.split()\nM = math.floor(int(dim[0]))\nN = math.floor(int(dim[1]))\nif M % 2 == 1:\n\tprint(int((M - 1) / 2 * N + N / 2))\nelse:\n\tprint(int(M / 2 * N))\n","from math import floor\n(m, n) = list(map(lambda x: int(x), input().strip().split()))\nprint(floor(m * n / 2))\n","(M, N) = input().split()\nnoOfSquares = int(M) * int(N) // 2\nprint(noOfSquares)\n","src = input()\nnum = int(src.split()[0]) * int(src.split()[1])\nif num % 2 == 0:\n\tprint(int(num / 2))\nelse:\n\tprint(int((num - 1) / 2))\n","import math\ns = input().strip().split()\nm = int(s[0])\nn = int(s[1])\nres = math.floor(m * n / 2)\nprint(res)\n","from math import floor\n(M, N) = input().strip().split()\n(M, N) = (int(M), int(N))\nprint(floor(M * N / 2))\n","import math\n(m, n) = map(int, input().split())\ndom_n = math.floor(m * n / (2 * 1))\nprint(dom_n)\n","(m, n) = input().split()\na = int(m)\nb = int(n)\nno = int(a * b / 2)\nprint(no)\n","A = input().split()\nm = int(A[0])\nn = int(A[1])\nprint(m * n // 2)\n","(p, g) = map(int, input().split())\nprint(int(g * p / 2))\n","mxn = input().split(' ')\nmxn = [int(i) for i in mxn]\nb = [0 for i in range(mxn[0])]\nboard = [b for i in range(mxn[1])]\ncount = 0\nfor i in board:\n\tfor j in i:\n\t\tcount += 1\nr = int(count / 2)\nprint(r)\n","numbers = [int(n) for n in input().split()]\nn = numbers[0]\nm = numbers[1]\nif n == 1 and m == 1:\n\tprint(0)\nelse:\n\tprint(int(m * n) // 2)\n","import math\nimport os\nimport random\nimport re\nimport sys\n\ndef matrixRotation(m, n):\n\ta = m * n\n\tc = a // 2\n\tc = c.__floor__()\n\tprint(c)\nmnr = input().rstrip().split()\nm = int(mnr[0])\nn = int(mnr[1])\nmatrixRotation(m, n)\n","(M, N) = map(int, input().split())\na = 2 * 1\nfor i in range(1, 15):\n\tb = M * N // a\nprint(b)\n","(m, n) = map(int, input().split())\n\ndef domino(m, n):\n\tfor i in range(17):\n\t\treturn m * n // 2\nprint(domino(m, n))\n","a = input('').split(' ')\nwidth = int(a[0])\nlength = int(a[1])\nsize = width * length\ndom = int(size / 2)\nprint(dom)\n","from sys import stdin, stdout\ninp = [int(x) for x in stdin.read().split()]\nn = inp.pop(0)\nk = inp.pop(0)\nboard = n * k\ndomino_size = 2\nmax_domino = board / domino_size\nmax_domino_result = int(max_domino)\nstdout.write(str(max_domino_result) + '\\n')\n","def main(n, m):\n\treturn n * m // 2\nn_m = input().split()\nn_m = [int(i) for i in n_m]\nprint(main(n_m[0], n_m[1]))\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\nif 1 <= m <= n <= 16:\n\ta = m * n // 2\n\tprint(a)\n","w = input().split(' ')\na = int(w[0])\nb = int(w[1])\nk = 0\nwhile 2 * (k + 1) <= a * b:\n\tk += 1\nprint(k)\n","def main():\n\tfrom sys import stdin, stdout\n\t(m, n) = [int(x) for x in input().split()]\n\tif m % 2 == 1 and n % 2 == 1:\n\t\tprint('{}'.format((m * n - 1) // 2))\n\telse:\n\t\tprint('{}'.format(m * n // 2))\nmain()\n","n = list(input().split(' '))\na = int(n[0]) * int(n[1])\nb = a // 2\nprint(b)\n","from sys import stdin\nimport math\n\ndef main():\n\ttable = [int(x) for x in stdin.readline().split()]\n\tprint(math.floor(table[0] * table[1] / 2))\nmain()\n","inp = list(map(int, input().split()))\nm = inp[0]\nn = inp[1]\narea = m * n\nres = area // 2\nprint(res)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\na = m * n\nb = 2\nc = a // 2\nprint(c)\n","number = list(map(int, input().split()))\nl = number[0] * number[1]\nprint(l // 2)\n","import math\na = input()\n(n, m) = a.split()\nl = int(n) * int(m) / 2\nprint(math.floor(l))\n","def solve():\n\t(x, y) = list(map(int, input().split()))\n\tresult = x * y // 2\n\tprint(result)\nsolve()\n","(x, y) = map(int, input().split())\nprod = x * y\nprint(int(prod / 2))\n","(a, b) = input().split()\n(a, b) = (int(a), int(b))\nc = a % 2\nd = b % 2\nif c == 1 and d == 1:\n\tx = (a * b - 1) / 2\nelse:\n\tx = a * b / 2\nprint('%d' % x)\n","(m, n) = map(int, input().split())\ns = m * n\np = 2\nprint(s // p)\n","def calc(a, b):\n\tf = a * b // 2\n\treturn f\n(a, b) = map(int, input().split())\nprint(calc(a, b))\n","(m, n) = [int(i) for i in input().split()]\nd = n * (m // 2)\nif m % 2 != 0:\n\td = d + n // 2\nprint(d)\n","arms = input()\ndata = arms.split()\narea = int(data[0]) * int(data[1])\nmax_placed = area // 2\nprint(max_placed)\n","nm = input().split()\nn = int(nm[0])\nm = int(nm[1])\np = n * m\nprint(p // 2)\n","nub = input()\nnub = nub.split(' ')\nmul = int(nub[0]) * int(nub[1])\nif mul % 2 != 0:\n\teq = (mul - 1) / 2\n\tprint(int(eq))\nelse:\n\teq = mul / 2\n\tprint(int(eq))\n","q = input('')\nt = 0\ndata = []\ns = 0\nwhile t < len(q):\n\tif q[t] == ' ':\n\t\tdata = data + [s]\n\t\ts = 0\n\telif t == len(q) - 1:\n\t\ts = s * 10 + float(q[t])\n\t\tdata = data + [s]\n\telse:\n\t\ts = s * 10 + float(q[t])\n\tt = t + 1\nm = data[0]\nn = data[1]\nprint(int(m * n // 2))\n","(a, b) = map(int, input().split())\nans = int()\nwhile a >= 2:\n\tans = ans + b\n\ta -= 2\nif a == 1:\n\tans = ans + b / 2\nprint(int(ans))\n","count = 0\nb = list(map(int, input().split()))\narea = b[0] * b[1]\nprint(area // 2)\n","l = [int(i) for i in input().split()[:2]]\nprint(l[0] * l[1] // 2)\n","ip = input()\nl1 = ip.split(' ')\nm = int(l1[0])\nn = int(l1[1])\nprint(int(m * n * 0.5))\n","(m1, n1) = input().split()\nm = int(m1)\nn = int(n1)\nif 1 <= m <= 16 and 1 <= m <= 16:\n\tc = int(m * n / 2)\n\tprint(c)\nelse:\n\tprint('dimension is not correct')\n","domino = [int(i) for i in input().split(' ')]\nprint(int(domino[0] * domino[1] / 2))\n","(l, b) = tuple(map(int, input().split()))\nprint(l * b // 2)\n","mn = input().split()\ncounter = 0\nassert 1 <= int(mn[0]) and int(mn[0]) <= int(mn[1]) and (int(mn[1]) <= 16)\nprint(int(mn[0]) * int(mn[1]) // 2)\n","i = input().split()\nprint(int(i[0]) * int(i[1]) // 2)\n","import math\n(M, N) = map(int, input().split())\nif N % 2 == 0 or M % 2 == 0:\n\tS = M * N / 2\nelse:\n\tQ = M // 2\n\tS = Q * N + N // 2\nprint(int(S))\n","n = input().split()\na = int(n[0])\nb = int(n[1])\nresult = a * b // 2\nprint(result)\n","(m, n) = [int(a) for a in input().split()]\nb = m * n\nprint((b - b % 2) // 2)\n","(m, n) = map(int, input().split())\ns = m * n\nnum = int(s / 2)\nprint(num)\n","(n, m) = map(int, input().split())\nK1 = n // 2 * m\nif n % 2 != 0:\n\tK1 = K1 + m // 2\nprint(K1)\n","(M, N) = [int(i) for i in input().split()]\nx = int(M * N / 2)\nprint(x)\n","integer = input()\nlist_integer = integer.split(' ')\nx = int(list_integer[0]) * int(list_integer[1])\ny = x // 2\nprint(y)\n","import math\na = input().split()\nm = int(a[0])\nn = int(a[1])\nmaindominos = m * math.floor(n / 2)\nif n % 2 != 0:\n\totherDominos = math.floor(m / 2)\nelse:\n\totherDominos = 0\nprint(maindominos + otherDominos)\n","(size_of_board_n, size_of_board_m) = [int(i) for i in input().split()]\nhow_much_space = size_of_board_n * size_of_board_m\nanswer = how_much_space // 2\nprint(answer)\n","(M, N) = map(int, input().split())\nif N / 2 == int(N / 2) or M / 2 == int(M / 2):\n\tx = int(M * N / 2)\nelse:\n\tx = int((M * N - 1) / 2)\nprint(x)\n","(m, n) = map(int, input().split())\nif 1 <= m <= n <= 16:\n\tarea = m * n\n\tprint(area // 2)\n","l = []\n(a, b) = map(int, input().split())\nif a == 1 and b == 1:\n\tl.append(0)\nelif a == 1 and b == 2 or (a == 2 and b == 1):\n\tl.append(1)\nelse:\n\tmmax = max(a, b)\n\tmmin = min(a, b)\n\tssum = 0\n\tif mmin % 2 == 0:\n\t\tssum = mmax // 1 * (mmin // 2)\n\telse:\n\t\tssum = mmax // 1 * (mmin // 2) + mmax // 2\n\tl.append(ssum)\nfor i in l:\n\tprint(i)\n","(m, n) = map(int, input().split())\narea = m * n\nif area % 2 != 0:\n\tarea -= 1\nprint(area // 2)\n","import math\n(M, N) = input().split()\nM = int(M)\nN = int(N)\nif 1 <= M <= N <= 16:\n\ta = math.floor(M / 2)\n\tb = int(a * N)\n\tc = M % 2\n\tif c == 0:\n\t\tprint(int(b))\n\telse:\n\t\td = N / 2\n\t\tprint(int(b + d))\nelse:\n\tprint('error')\n","a = input().split()\nb = int(a[0])\na = int(a[1])\ns = 0\ns = s + b // 2 * a\nif b % 2 == 1:\n\ts = s + a // 2\nprint(s)\n","def domino(m, n):\n\treturn m * n // 2\n\ndef main():\n\ts = input().split()\n\tprint(domino(int(s[0]), int(s[-1])))\nmain()\n","(a, b) = [int(i) for i in input().split()]\nprint('{:d}'.format(a * b // 2))\n","def domino_layout(m, n):\n\tD = m * n // 2\n\treturn D\nl = [int(x) for x in input().split()]\n(m, n) = l\nprint(domino_layout(m, n))\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nprint('%d' % (a * b / 2))\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nD = M * N // 2\nprint(D)\n","import math\n(x, y) = [int(a) for a in input().split()]\nans = math.floor(x * y / 2)\nprint(ans)\n","a = input().split()\nm = int(a[0])\nn = int(a[1])\nb = 0\nif 1 <= m <= n <= 16:\n\tb = m * n // 2\nprint(b)\n","_ = input().split(' ')\nprint(int(_[0]) * int(_[1]) // 2)\n","input_data = input()\nlist_we_use = input_data.split(' ')\nfinal_list = []\nfor i in list_we_use:\n\tfinal_list.append(int(i))\nq = final_list[0] * final_list[1]\nprint(q // 2)\n","def sol(x, y):\n\tprint(x * y // 2)\n(m, n) = input().split()\nsol(int(m), int(n))\n","n = input().split()\nsize = int(n[0]) * int(n[1])\nans = size // 2\nprint(ans)\n","def solve(M, N):\n\ttileArea = 2 * 1\n\tboardArea = M * N\n\tprint(int(boardArea / tileArea))\n(M, N) = map(int, input().split())\nsolve(M, N)\n","(m, n) = map(int, input().split())\nfor i in range(1, 257):\n\tif i * 2 > m * n:\n\t\tprint(i - 1)\n\t\texit()\n","import sys\n\ndef rs():\n\treturn sys.stdin.readline().rstrip()\n\ndef ri():\n\treturn int(sys.stdin.readline())\n\ndef ria():\n\treturn list(map(int, sys.stdin.readline().split()))\n\ndef ws(s):\n\tsys.stdout.write(s)\n\tsys.stdout.write('\\n')\n\ndef wi(n):\n\tsys.stdout.write(str(n))\n\tsys.stdout.write('\\n')\n\ndef wia(a, sep=' '):\n\tsys.stdout.write(sep.join([str(x) for x in a]))\n\tsys.stdout.write('\\n')\n\ndef solve(n, m):\n\tif n * m % 2 == 0:\n\t\treturn n * m // 2\n\treturn min(n, m) * (max(n, m) // 2) + min(n, m) // 2\n\ndef main():\n\t(n, m) = ria()\n\twi(solve(n, m))\nmain()\n","(M, N) = [int(x) for x in input().split()]\nsquare = M * N\nnum = square // 2\nprint(num)\n","import sys\n\ndef main():\n\tmatrix = []\n\tlista = []\n\tn = list(map(int, sys.stdin.readline().strip().split(' ')))\n\tmult = n[0] * n[1]\n\tresultado = mult // 2\n\tprint(resultado)\nmain()\n","def main():\n\t(m, n) = (int(i) for i in input().split())\n\tif n == 1 and m == 1:\n\t\tres = 0\n\tif m % 2 == 0 or n % 2 == 0:\n\t\tres = n * m // 2\n\telse:\n\t\t(m, n) = (n, m) if n > m else (m, n)\n\t\tres = (m - 1) * n // 2 + (n - 1) // 2\n\tprint(res)\nmain()\n","inp = list(map(int, str(input()).split(' ')))\narea = inp[0] * inp[1]\nprint(area // 2)\n","def calculate_dominos(length, breadth):\n\tresult = 0\n\tif length > 1 or breadth > 1:\n\t\tresult += length // 2\n\t\tif length % 2 == 0:\n\t\t\tremaining_length = 0\n\t\telse:\n\t\t\tremaining_length = 1\n\t\tresult += (breadth - 1) * result\n\t\tif remaining_length == 1:\n\t\t\tresult += breadth // 2\n\treturn result\n[length, breadth] = list(map(int, input().strip().split(' ')))\nresult = calculate_dominos(length, breadth)\nprint(result)\n","(m, n) = input().split(' ')\nif int(m) / 2 * int(n) > int(m) * int(n) / 2:\n\tprint(int(int(m) / 2 * int(n)))\nelse:\n\tprint(int(int(m) * int(n) / 2))\n","(M, N) = list(map(int, input().split()))\ndomino_area = 2\nsqr = M * N\nprint(sqr // domino_area)\n","(m, n) = map(int, input().split())\nareal = m * n\nif areal % 2 == 0:\n\tbrikker = areal / 2\n\tprint(int(brikker))\nelse:\n\tbrikker = (areal - 1) / 2\n\tprint(int(brikker))\n","m = input().split()\nm = '*'.join(m)\nm = eval(m)\nm = m / 2\nprint(int(m))\n","(a, b) = map(int, input().split())\nres = a * b\nold = 0\ni = 0\nwhile 2 * i <= res:\n\told = i\n\ti += 1\nprint(old)\n","inpt = input().split()\nm = int(inpt[0])\nn = int(inpt[1])\nif (m, n >= 1 and m, n <= 16):\n\tprint(int(m * n / 2))\n","(a, b) = [int(i) for i in input().split(' ')]\nanswer = int()\nif a < b:\n\t(a, b) = (b, a)\nprint(a * (b // 2) + b % 2 * (a // 2))\n","import math\nn = list(map(int, input().split()))\nif n[0] * n[1] % 2 == 0:\n\tprint(int(n[0] * n[1] / 2))\nelse:\n\tprint(math.floor(n[0] * n[1] / 2))\n","import math\n(n, k) = map(int, input().split())\nif n <= 1 and k <= 1:\n\tprint(0)\nelse:\n\tprint(math.floor(n * k * 0.5))\n","size = list(map(int, input().split()))\na1 = size[1] * size[0]\nprint(a1 // 2)\n","def func(n, m):\n\tif m < 2 and n < 2:\n\t\treturn 0\n\tif n == 0 or m == 0:\n\t\treturn 0\n\tif n == 1:\n\t\treturn m // 2\n\tif m == 1:\n\t\treturn n // 2\n\tif n > 1:\n\t\treturn m + func(n - 2, m)\n\telse:\n\t\treturn n + func(n, m - 2)\n(n, m) = map(int, input().split())\nprint(func(n, m))\n","input1 = input().split()\n(m, n) = (int(input1[0]), int(input1[-1]))\nif m * n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m * n - 1) / 2))\n","import math\nreq = input().split(' ')\nfield = int(req[0]) * int(req[1])\nres = field / 2\nprint(math.floor(res))\n","(i, j) = input().split()\nk = int(i) * int(j)\nl = k // 2\nprint(l)\n","Dim = list(map(int, input().split()))\nif Dim[0] % 2 == 0:\n\tNum = Dim[0] / 2 * Dim[1]\n\tprint(int(Num))\nelif Dim[1] % 2 == 0:\n\tNum = Dim[1] / 2 * Dim[0]\n\tprint(int(Num))\nelse:\n\tNum = (Dim[0] - 1) * Dim[1] / 2 + (Dim[1] - 1) / 2\n\tprint(int(Num))\n","from math import floor\nx = input()\nx = x.split(' ')\nm = int(x[0])\nn = int(x[1])\nif m % 2 == 0:\n\tdn = m / 2 * n\nelse:\n\tdn = (m - 1) / 2 * n + floor(n / 2)\nprint(int(dn))\n","(m, n) = list(map(int, input().split()))\nd = m * n // 2\nprint(d)\n","def main():\n\tn_m = str(input())\n\tn = int(n_m.split(' ')[0])\n\tm = int(n_m.split(' ')[1])\n\tcnt = 0\n\tsp = n * m\n\tcnt = int(sp / 2)\n\tprint(cnt)\nmain()\n","def domino():\n\t(a, b) = map(int, input().split())\n\tif a * b % 2 == 0:\n\t\tprint(int(a * b / 2))\n\telse:\n\t\tprint(a * b // 2)\ndomino()\n","import sys\nimport math\nx = sys.stdin.readline().split()\ny = int(x[1])\nx = int(x[0])\nprint(math.floor(x * y / 2))\n","input = str(input())\nmultiplication = int(input.split(' ')[0]) * int(input.split(' ')[1])\nsolution = multiplication / 2\nprint(int(solution))\n","(M, N) = map(int, input().split())\ns = M * N\na = 2 * 1\nx = s // a\nprint(x)\n","(x, y) = list(map(int, input().split()))\nif x * y % 2 == 1:\n\tprint((x * y - 1) // 2)\nelse:\n\tprint(x * y // 2)\n","import math\n(m, n) = tuple(map(int, input().split()))\nif m == 1:\n\tprint(math.floor(n / 2))\nelif n == 1:\n\tprint(math.floor(m / 2))\nelse:\n\tmIsOdd = m % 2 != 0\n\tx = math.floor(m / 2)\n\ty = 0\n\tif mIsOdd:\n\t\ty = math.floor(n / 2)\n\tprint(x * n + y)\n","from sys import stdin\n(m, n) = map(int, stdin.readline().split())\nif m == 1 and n == 1:\n\tprint(0)\nelif m < n:\n\ta = n // 2\n\tb = n % 2\n\tprint(m * a + m * b // 2)\nelse:\n\ta = m // 2\n\tb = m % 2\n\tprint(n * a + n * b // 2)\n","m = list(map(int, input().split()))\nif max(m) % 2 == 0:\n\tprint(min(m) * (max(m) // 2))\nelse:\n\tprint(min(m) * (max(m) // 2) + min(m) // 2)\n","M = input().split(' ')\ndomino = 2\nhasil = int(M[0]) * int(M[1]) // 2\nprint(hasil)\n","a = input().strip().split(' ')\nm = int(a[0])\nn = int(a[1])\nif m >= 1 and m <= n and (n <= 16):\n\tprint(m * n // 2)\n","def get_max_dominoes(n, m):\n\tif n == 1 and m == 1:\n\t\treturn 0\n\tif m == 2:\n\t\treturn n\n\tif n == 2:\n\t\treturn m\n\tif m > n:\n\t\treturn n + get_max_dominoes(n, m - 2)\n\treturn m + get_max_dominoes(n - 2, m)\nsize = [int(i) for i in input().split()]\nprint(get_max_dominoes(size[0], size[1]))\n","(m, n) = input().split()\n(l, b) = (int(m), int(n))\narea = l * b\nprint(int(area / 2))\n","import math\n(m, n) = map(int, input().split())\nmaxnum = 0\nif 1 <= m <= n <= 16:\n\tarea = m * n\n\tif area % 2 == 0:\n\t\tmaxnum = int(area / 2)\n\telse:\n\t\tmaxnum = math.floor(area / 2)\nprint(maxnum)\n","import math\nx = list(map(int, input().split()))\nm = x[0] * x[1]\nprint(math.floor(m / 2))\n","import re, math\nx = re.split(' ', input())\nfor i in range(0, len(x)):\n\tx[i] = int(x[i])\nprint(math.floor(x[0] * x[1] / 2))\n","import math\n(m, n) = map(int, input().split())\narea = m * n\ndomino = area // 2\nprint(domino)\n","(r, c) = map(int, input().split())\nans = 0\nr1 = r\nwhile r1 >= 2:\n\tans += c\n\tr1 -= 2\nif r % 2 == 1:\n\tans += c // 2\nprint(ans)\n","input_list = input().split()\nm = eval(input_list[0])\nn = eval(input_list[1])\ncounter = 0\ncounter += n * (m // 2)\nif m % 2 == 1:\n\tcounter += n // 2\nprint(counter)\n","a = input()\n(c, v) = a.split()\nc = int(c)\nv = int(v)\nprint(c * v // 2)\n","import sys\n(n, m) = map(float, input().split())\nprint(round(n * m // 2))\n","(side1, side2) = input().split()\nresult = int(side1) * int(side2) / 2\nprint(int(result))\n","(n, k) = [int(i) for i in input().split()]\nar = n * k\nprint(ar // 2)\n","num_list = list(map(int, input().split()))\nm = num_list[0]\nn = num_list[1]\nif m % 2 == 0:\n\tnum = m // 2 * n\n\tprint(num)\nelif n % 2 == 0:\n\tnum = n // 2 * m\n\tprint(num)\nelse:\n\tnum = m // 2 * n + n // 2\n\tprint(num)\n","def answer(m, n):\n\tproduct = m * n\n\tif product % 2 == 1:\n\t\tans = (product - 1) // 2\n\t\treturn ans\n\tans = product // 2\n\treturn ans\nsize = input()\nsize = size.split(' ')\nnew = [int(each) for each in size]\nprint(answer(new[0], new[1]))\n","(b, c) = list(map(int, input().strip().split()[:2]))\nprint(int(b * c / 2))\n","def tile(x, y):\n\treturn x * y // 2\n(x, y) = list(map(int, input().split(' ')))\nprint(tile(x, y))\n","(m, n) = map(int, input().split())\nc = 0\nfreeCells = 0\nfor i in range(m):\n\tc += n // 2\n\tif n / 2 % 1 == 0.5:\n\t\tfreeCells += 1\n\t\tif freeCells == 2:\n\t\t\tc += 1\n\t\t\tfreeCells = 0\nprint(c)\n","class main:\n\n\tdef __init__(self):\n\t\tMN = input()\n\t\tMN = MN.split(' ', 1)\n\t\tM = int(MN[0])\n\t\tN = int(MN[1])\n\t\ts = M * N\n\t\tif s % 2 == 0:\n\t\t\tdomino = s / 2\n\t\t\tprint(int(domino))\n\t\telif s % 2 != 0:\n\t\t\ts = s - 1\n\t\t\tdomino = s / 2\n\t\t\tprint(int(domino))\na = main()\n","lst = [int(x) for x in input().split(' ')]\nprint(lst[0] * lst[1] // 2)\n","from sys import stdin\ndata = stdin.readline().split()\nindex = 0\nmult = 1\nresult = 0\nfor item in data:\n\tdata[index] = int(item)\n\tindex += 1\nfor item in data:\n\tmult *= item\nresult = int(mult / 2)\nprint(result)\n","import math\n\ndef piling(mm, nn):\n\tif mm % 2 == 0:\n\t\treturn mm / 2 * nn\n\telif nn % 2 == 0:\n\t\treturn nn / 2 * mm\n\telse:\n\t\treturn piling(mm - 1, nn) + math.floor(nn / 2)\n(m, n) = input().split()\nm = int(m)\nn = int(n)\nprint(int(piling(m, n)))\n","(m, n) = tuple(map(int, input().split()))\narea = m * n\nre = area // 2\nprint(re)\n","(M, N) = input().split()\nm = int(M)\nn = int(N)\narea = m * n\nprint(area // 2)\n","s = input().split()\nm = int(s[0])\nn = int(s[1])\nar = m * n\nz = ar // 2\nprint(z)\n","(N, M) = map(int, input().split())\nn = N % 2\nm = M % 2\nif N == 1:\n\tprint(M // 2)\nelif M == 1:\n\tprint(N // 2)\nelse:\n\tprint(int(N * m // 2 + M * n // 2 + (M - m) * (N - n) / 2))\n","import math\n(m, n) = [int(i) for i in input().split()]\nif m % 2 == 0:\n\tprint(int(m / 2 * n))\nelse:\n\tprint(int((m - 1) / 2 * n + math.floor(n / 2)))\n","(a, b) = map(int, input().split())\nif a < b:\n\tc = a\n\ta = b\n\tb = c\nd = a % 2\ne = b % 2\nfloat(a)\nfloat(b)\nif d == 0 or e == 0:\n\tanswer = a * b / 2\nif d != 0 and e != 0:\n\tanswer = (a * b - 1) / 2\nprint(int(answer))\n","(m, n) = list(map(int, input().split()))\nx = m // 2\ny = n // 2\nprint(min(x * y + (m - x) * (n - y), x * (n - y) + (m - x) * y))\n","(x, k) = [int(x) for x in input().split()]\narea = x * k\nprint(area // 2)\n","(m, n) = [int(x) for x in input().split()]\narea_board = m * n\nprint(area_board // 2)\n","z = [int(x) for x in input().split(' ')]\nprint(z[0] * z[1] // 2)\n","import sys\nimport math\ninputs = sys.stdin.readline().split()\nm = int(inputs[0])\nn = int(inputs[1])\na = m % 2\nb = n % 2\nif a == 0:\n\tx = m * n\n\tx = 0.5 * x\n\tx = int(x)\n\tprint(x)\nelif b == 0:\n\tx = m * n\n\tx = 0.5 * x\n\tx = int(x)\n\tprint(x)\nelse:\n\te = m - 1 + (n - 1)\n\tf = (m - 1) * (n - 1)\n\tx = e + f\n\tx = 0.5 * x\n\tx = int(x)\n\tprint(x)\n","(m, n) = [int(__) for __ in input().strip().split()]\nprint(m // 2 * n + m % 2 * n // 2)\n","n = list(map(int, input().split()))\nif n[0] % 2 == 0:\n\tc = n[0] / 2 * n[1]\nelif n[1] % 2 == 0:\n\tc = n[1] / 2 * n[0]\nelse:\n\tc = (n[0] - 1) / 2 * n[1] + (n[1] - 1) / 2\nprint(int(c))\n","(a, b) = list(map(int, input().split()))\nd = a * b\nif d % 2 == 0:\n\teven = d // 2\n\tprint(even)\nelse:\n\todd = (d - 1) // 2\n\tprint(odd)\n","info = input().split()\narea = 1\nfor i in range(0, 2):\n\tarea = area * int(info[i])\nprint(area // 2)\n","ints = input().split()\nnumber = int(ints[0]) * int(ints[1])\nif number % 2 == 0:\n\tprint(int(number / 2))\nelse:\n\tprint(int((number - 1) / 2))\n","(length_of_board, width_of_board) = input().split()\nlength_of_board = int(length_of_board)\nwidth_of_board = int(width_of_board)\nif length_of_board >= 1 and length_of_board <= 16:\n\tif width_of_board >= 1 and width_of_board <= 16:\n\t\tmax_area = length_of_board * width_of_board\n\t\tmax_dominoes = int(max_area / 2)\n\t\tprint(max_dominoes)\n","(n, m) = map(int, input().split())\nprint(m * n // 2, flush=True)\n","def main():\n\t(m, n) = list(map(int, input().split()))\n\tif m == n == 1:\n\t\tprint(0)\n\telif m == 1:\n\t\tprint(n // 2)\n\telif n == 1:\n\t\tprint(m // 2)\n\telse:\n\t\tprint(n // 2 * m + m // 2 if n % 2 != 0 else n // 2 * m)\nmain()\n","n = list(map(int, input().split()))\nn1 = n[0]\nn2 = n[1]\na = 2 * 1\nb = n1 * n2\nprint(int(b / a))\n","x = input()\nx1 = x.split(' ')\nm = int(x1[0])\nn = int(x1[1])\nprint(m * n // 2)\n","(x, y) = [int(z) for z in input().split()]\nmult = x * y\nif mult % 2 == 0:\n\tprint(int(mult / 2))\nelse:\n\tprint(int((mult - 1) / 2))\n","(length, width) = input().split(' ')\nlength = int(length)\nwidth = int(width)\narea = width * length\ndominoNumber = 0\nwhile dominoNumber * 2 + 2 <= area:\n\tdominoNumber = dominoNumber + 1\nprint(dominoNumber)\n","def main():\n\t(n, m) = map(int, input().split())\n\ttotalSquares = n * m\n\tprint(totalSquares // 2)\nmain()\n","m_n = input().strip().split()\n(m, n) = (int(m_n[0]), int(m_n[1]))\nprint(m * n // 2)\n","variables = [int(x) for x in input().split()]\nwidth = variables[0]\nheight = variables[1]\nprint(width * height // 2)\n","x = input()\nx = x.split(' ')\nm = int(x[0])\nn = int(x[1])\narea = m * n\nnum = area // 2\nprint(num)\n","l = lambda : map(int, input().split())\n(a, b) = l()\nc = a * b\nd = c // 2\nprint(d)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 0:\n\ttotal = m // 2 * n\nelse:\n\ttotal = m // 2 * n\n\tk = n // 2\n\ttotal = total + k\nprint(total)\n","edges = input('')\nm = edges[0:edges.index(' ')]\nn = edges[edges.index(' ') + 1:]\nm = int(m)\nn = int(n)\nif m % 2 == 0:\n\tyatayKenar1 = int(m / 2)\n\tuzunKenar1 = n\n\tolasilik1 = yatayKenar1 * uzunKenar1\nelse:\n\tyatayKenar1 = int(m / 2)\n\tuzunKenar1 = n\n\tolasilik1 = yatayKenar1 * uzunKenar1\n\tkalan1 = int(n / 2)\n\tolasilik1 += kalan1\nif n % 2 == 0:\n\tyatayKenar2 = m\n\tuzunKenar2 = int(n / 2)\n\tolasilik2 = yatayKenar2 * uzunKenar2\nelse:\n\tyatayKenar2 = m\n\tuzunKenar2 = int(n / 2)\n\tolasilik2 = yatayKenar2 * uzunKenar2\n\tkalan2 = int(m / 2)\n\tolasilik2 += kalan2\nif olasilik1 > olasilik2:\n\tprint(olasilik1)\nelse:\n\tprint(olasilik2)\n","(a, b) = list((int(x) for x in input().split()))\nc = a * b\nn = c // 2\nprint(n)\n","(m, n) = list(map(int, input().split()))\ns = m * n\nk = s // 2\nprint(k)\n","(m, n) = [int(m) for m in input().split()]\nc = int(m * n)\nif c % 2 == 0:\n\tprint(c // 2)\nelse:\n\tprint(c // 2)\n","(k, l) = map(int, input().split())\nans = k * l // 2\nprint(ans)\n","import math\n(length_m, width_m) = map(int, input().split())\nboardArea = length_m * width_m\ndomino = 2\nprint(math.floor(boardArea / domino))\n","(m, n) = input('').split()\nm = int(m)\nn = int(n)\ncell = m * n\nprint(cell // 2)\n","L = [int(x) for x in input().split(' ')]\ntemp = L[0] * L[1]\nprint(int(temp / 2))\n","m = input()\nli = m.split()\na = int(li[0])\nb = int(li[1])\nc = a * b / 2\nprint(int(c))\n","def Main():\n\t(n, m) = map(int, input().split())\n\tprint(n * m // 2)\nMain()\n","(n, m) = map(int, input().split())\nboardArea = n * m\ndominoArea = 2 * 1\nprint(int(boardArea / dominoArea))\n","(n, m) = map(int, input().split())\nc = int(m * n)\nif c % 2 == 0:\n\tz = c / 2\nelse:\n\tz = (c - 1) / 2\nprint(int(z))\n","(M, N) = map(int, input().split())\nmulti = M * N\ncont = 0\nwhile multi > 1:\n\tif multi % 2 == 0:\n\t\tmulti -= 2\n\t\tcont += 1\n\telse:\n\t\tmulti -= 1\nprint(cont)\n","s = input()\nlst = list(map(int, s.split()))\na = lst[0]\nb = lst[1]\nif a < 2 and b < 2:\n\tprint(0)\nelse:\n\tans = a // 1 * (b // 2)\n\tif b % 2 == 1 and a >= 2:\n\t\tans += a // 2\n\tprint(ans)\n","import os\n(M, N) = os.read(0, 100000).strip().decode('utf-8').split(' ')\nprint(int(M) * int(N) // 2)\n","__author__ = 'widoc'\nimport math\n(m, n) = map(int, input().split())\nprint(math.floor(m / 2) * n + m % 2 * math.floor(n / 2))\n","(a, b) = [int(temp) for temp in input().split()]\nprint(a * b // 2)\n","(m, n) = list(map(int, input().split()))\nav = m * n\nprint(av // 2)\n","(m, n) = list(map(int, input().split()))\nif m * n % 2 == 0:\n\tjd = m * n / 2\n\tprint(int(jd))\nelse:\n\tjd = m * n / 2\n\tessa = jd - 0.5\n\tprint(int(essa))\n","(m, n) = input().split(' ')\nm = int(m)\nn = int(n)\na = m * n\nx = a / 2\nx = int(x)\nprint(x)\n","(a, b) = map(int, input().split())\nnumber = 0\nif a % 2 == 0 or b % 2 == 0:\n\tnumber = int(a * b / 2)\nelse:\n\tnumber = int(a * b // 2)\nprint(number)\n","(a, b) = input().split(' ')\nm = int(a)\nn = int(b)\nif m % 2 != 0 or n % 2 != 0:\n\tif m >= n:\n\t\tx = m // 2\n\t\to = x * n\n\t\td = m % 2 * n // 2\n\t\tprint(int(o + d))\n\telse:\n\t\tx = n // 2\n\t\to = x * m\n\t\td = n % 2 * m // 2\n\t\tprint(int(o + d))\nelif m >= n:\n\tx = m // 2\n\to = x * n\n\tprint(o)\nelse:\n\tx = n // 2\n\to = x * m\n\tprint(o)\n","(m, n) = input().split(' ')\nwynik = int(int(m) * int(n) / 2)\nprint(wynik)\n","a = input()\nb = a.split(' ')\nb[0] = int(b[0])\nb[1] = int(b[1])\nc = b[0] * b[1]\nk = c // 2\nprint(k)\n","mat = list(map(int, input().strip().split()))\nprint(int(mat[0] * mat[1] / 2))\n","import math\n\ndef main():\n\t(m, n) = input().split()\n\tm = int(m)\n\tn = int(n)\n\tnum = math.floor(m * n / 2)\n\tprint(num)\nmain()\n","t = lambda : map(int, input().split())\n(m, n) = t()\nprint(m * n // 2)\n","(m, n) = [int(val) for val in input().split(' ')]\ndominoes = m // 2\ndominoes *= n\nif m % 2:\n\tdominoes += n // 2\nprint(dominoes)\n","(x, y) = input().split()\np = int(x) * int(y)\no = p // 2\nprint(o)\n","(N, M) = map(int, input().split())\nnumber = N // 2 * M\nif N % 2 == 1:\n\tnumber = number + M // 2\nprint(number)\n","(m, n) = map(int, input().split())\na = m\nb = n // 2\ncount = a * b\nif n % 2 != 0:\n\tcount += m // 2\nprint(count)\n","(N, M) = map(int, input().split())\nvalue = 0\nif N % 2 == 0:\n\tvalue += N // 2 * M\nelse:\n\tvalue += N // 2 * M + M // 2\nprint(value)\n","a = list(map(int, input().split()))\nw = a[0] * a[1]\nresult = w // 2\nprint(result)\n","firstInput = input().split()\nproduct = int(firstInput[0]) * int(firstInput[1])\nif product % 2 == 0:\n\tprint(int(product / 2))\nelse:\n\tprint(int((product - 1) / 2))\n","a = input()\nli = a.split()\ns = int(li[0])\nb = int(li[1])\nx = s * b\nres = x // 2\nprint(res)\n","mn = input()\n(m, n) = map(lambda x: int(x), mn.split(' '))\nif m < n:\n\t(m, n) = (n, m)\nodd = n % 2\nresult = m * (n - odd) // 2\nresult += odd * (m // 2)\nprint(result)\n","(n, m) = map(int, input().split())\ns = m * n\nans = s // 2\nprint(ans)\n","def ans(arr):\n\treturn mn[0] * mn[1] // 2\nmn = list(map(int, input().strip().split()))\nprint(ans(mn))\n","(width, height) = [int(i) for i in input().split()]\nprint(width * height // 2)\n","line = input()\ni = int(line.split(' ')[0])\nj = int(line.split(' ')[1])\nans = 0\nif i % 2:\n\tans += i // 2 * j\n\tans += j // 2\nelse:\n\tans += i / 2 * j\nprint(int(ans))\n","(m, n) = [int(i) for i in input().split()]\nprint(str(int(m * n / 2)))\n","import math\n(a, b) = list(map(int, input().split()))\nprint(math.floor(a * b / 2))\n","(m, n) = list(map(int, input().split(' ')))\nmaxi = int(m * n / 2)\nprint(maxi)\n","(n, m) = input().split()\np = int(n) * int(m)\nd = 2\ns = 0\nfor i in range(p):\n\tif p < 2:\n\t\tprint(s)\n\t\tbreak\n\tp -= d\n\ts += 1\n","(w, l) = [int(x) for x in input().split()]\nif w % 2 == 0 or l % 2 == 0:\n\tprint(int(w * l * 0.5))\nelse:\n\tprint(w * l // 2)\n","import math\nn = list(input().split(' '))\narea = int(n[0]) * int(n[1])\nans = math.floor(area / 2)\nprint(ans)\n","from sys import stdin\n\ndef cantidad_dominos(m, n):\n\ta = m * n\n\tb = a // 2\n\treturn b\n\ndef main():\n\tlinea = stdin.readline().strip()\n\twhile len(linea) != 0:\n\t\t(m, n) = [int(x) for x in linea.split()]\n\t\tprint(cantidad_dominos(m, n))\n\t\tlinea = stdin.readline().strip()\nmain()\n","dim = list(map(int, input().split()))\nprint(dim[0] * dim[1] // 2)\n","x = input()\nX = x.split()\nx0 = int(X[0])\nx1 = int(X[1])\nx = x0 * x1 // 2\nprint(x)\n","sp = input().split(' ')\n(m, n) = (int(sp[0]), int(sp[1]))\nif m & 1 == 0:\n\tans = m // 2 * n\nelse:\n\tans = m // 2 * n + n // 2\nprint(ans)\n","list = input().split()\nnum = [int(x) for x in list]\nif num[0] % 2 == 0:\n\tprint(num[0] // 2 * num[1])\nelse:\n\tprint(num[0] // 2 * num[1] + num[1] // 2)\n","(a, b) = map(int, input().split())\ns = 2 * 1\nn = a * b\nprint(int(n / s))\n","s = input()\na = s.split()\nm = int(a[0])\nn = int(a[1])\nprod = m * n\ndom = prod / 2\nprint(int(dom))\n","s = input()\ns = s.split(' ')\nsq = int(s[0]) * int(s[1])\nprint(sq // 2)\n","values = input().split()\nprint(int(int(values[0]) * int(values[1]) / 2))\n","(hang, lie) = map(int, input().split())\nif hang % 2 == 1 and lie % 2 == 1:\n\tprint(str(int((hang * lie - 1) / 2)))\nelse:\n\tprint(str(int(hang * lie / 2)))\n","(m, n) = map(int, input().strip().split())\nx = m * n\nprint(x // 2)\n","(m, n) = map(int, input().split(' '))\nd = 2 * 1\nb = m * n\nprint(b // d)\n","lst = input()\nlst = lst.split(' ')\nn = int(lst[0])\nm = int(lst[1])\nprint(m * n // 2)\n","(x, y) = map(int, input().split())\nt = x * y\nprint(t // 2)\n","m = input().split()\np = map(int, m)\nprint(int(m[0]) * int(m[1]) // 2)\n","measure = list(map(int, input().split(' ')))\nprint(measure[0] * measure[1] // 2)\n","import math\n\ndef count(m, n, ansSoFar):\n\tif m >= n:\n\t\tm = m - 2\n\t\tn = n - 1\n\telse:\n\t\tn = n - 2\n\t\tm = m - 1\n\tif m > -1 and n > -1:\n\t\tansSoFar = ansSoFar + 1\n\t\treturn count(m, n, ansSoFar)\n\telse:\n\t\treturn ansSoFar\n(m, n) = map(int, input().split())\nprint(math.floor(m * n / 2))\n","l = list(map(int, input().split()))\nm = l[0]\nn = l[1]\nc1 = n * (m // 2)\nif m % 2 != 0:\n\tc1 += n // 2\nprint(c1)\n","c = input().split()\nx = eval('*'.join(c)) // 2\nprint(x)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\nA2 = 2\nif 1 <= M <= N <= 16:\n\tA1 = M * N\n\tA3 = int(A1 / A2)\n\tprint(A3)\n","import sys\nimport os\n\ndef int_array():\n\treturn list(map(int, input().strip().split()))\n\ndef str_array():\n\treturn input().strip().split()\n\ndef gcd(a, b):\n\tif b == 0:\n\t\treturn a\n\treturn gcd(b, a % b)\n\ndef take_input():\n\tif os.environ.get('check'):\n\t\tsys.stdin = open('input.txt', 'r')\n\t\tsys.stdout = open('output.txt', 'w')\ntake_input()\n(n, m) = int_array()\nprint(n * m // 2)\n","N = list(map(int, input().split()))\nD = N[0] * N[1]\nRes = D // 2\nprint(Res)\n","import sys\nimport math\ninput = sys.stdin.readline\nprint = sys.stdout.write\n(m, n) = tuple(map(int, input().split()))\nprint(str(m * n // 2))\n","import math\ninput_str = input().split()\nboardSize = int(input_str[0]) * int(input_str[1])\ntotal = math.floor(boardSize / 2)\nprint(total)\n","(n, k) = map(int, input().split())\nb = n * k\nanswer = b // 2\nprint(answer)\n","x = input()\nsez = x.split()\nm = int(sez[0])\nn = int(sez[1])\nzmnoz = m * n\nif zmnoz % 2 == 0:\n\tprint(int(zmnoz / 2))\nelse:\n\tprint(int(zmnoz / 2 - 0.5))\n","import math as m\n(x, y) = map(int, input().split())\nz = m.floor(x * y / (1 * 2))\nprint(z)\n","[m, n] = input().split()\nm = int(m)\nn = int(n)\ni = int(m / 2)\na = i * n\nif m % 2 != 0:\n\tj = int(n / 2)\n\ta += j\nprint(a)\n","Values = input()\nValues = Values.split(' ')\nLength = int(Values[0])\nBreadth = int(Values[1])\nArea = Length * Breadth\nDomino_Area = 2\nFits = Area / int(Domino_Area)\nprint(int(Fits))\n","(M, N) = list(map(int, input().split()))\nif 1 <= M <= N <= 16:\n\tresult = M * N // 2\n\tprint(result)\n","__author__ = 'Mahsa'\ninputs = input().split(' ')\nm = int(inputs[0])\nn = int(inputs[1])\nif m % 2 == 0:\n\tres = m / 2 * n\nelif n % 2 == 0:\n\tres = n / 2 * m\nelse:\n\tres = (m - 1) / 2 * n + (n - 1) / 2\nprint(int(res))\n","from math import floor\n(m, n) = [int(i) for i in input().strip().split()]\narea = m * n\nprint(int(floor(area / 2)))\n","import sys\nmn = sys.stdin.readline().split(' ')\nm = int(mn[0])\nn = int(mn[1])\nmn2 = m * n\nres = int(mn2 / 2)\nprint(res)\n","(n, m) = map(int, input().split())\nif n >= m:\n\t(n, m) = (m, n)\nver = m // 2\ntot = n * ver\nrem = m % 2\next = 0\nif rem >= 1:\n\tif n >= 2:\n\t\tp = n // 2\n\t\text = p * rem\ntot = tot + ext\nprint(tot)\n","import math\nin_str = input().split()\n(M, N) = (int(in_str[0]), int(in_str[1]))\nprint(int(M * N / 2))\n","dimensions = input()\ndimensions = dimensions.split()\ndimension = []\nfor i in dimensions:\n\tnew_val = int(i)\n\tdimension.append(new_val)\narea = dimension[0] * dimension[1]\nif area % 2 == 0:\n\tno_dominos = area / 2\nelse:\n\tno_dominos = (area - 1) / 2\nprint(int(no_dominos))\n","(m, n) = [int(x) for x in input().split()]\narea = m * n\nif area % 2 == 0:\n\tnumber = area / 2\nelse:\n\tnumber = (area - 1) / 2\nc = int(number)\nprint(c)\n","from functools import reduce\nprint(reduce(lambda a, b: a * b, map(int, input().split())) // 2)\n","num = list(map(int, input().rstrip().split()))\nprint(int(num[0] * num[1] / 2))\n","a = lambda x, y: x * y\n[x, y] = input().split()\nprint(a(int(x), int(y)) // 2)\n","import sys\ninput = sys.stdin.readline\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef insr():\n\ts = input()\n\treturn list(s[:len(s) - 1])\n\ndef invr():\n\treturn map(int, input().split())\ninputs = inlt()\n(M, N) = (inputs[0], inputs[1])\narea = M * N\nans = area // 2\nprint(ans)\n","import sys\nn = 0\nfor l in sys.stdin:\n\tfor k in l.split():\n\t\tif n == 0:\n\t\t\tx = int(k)\n\t\t\tn = n + 1\n\t\telse:\n\t\t\ty = int(k)\n\tprint(x * y // 2)\n\tbreak\n","from math import ceil\n(m, n) = map(int, input().split())\no = ceil(m * n / 2)\nif n % 2 != 0:\n\tif m % 2 != 0:\n\t\to -= 1\nprint(o)\n","(M, N) = [int(x) for x in input().split()]\ns = M * N\nprint(int(s / 2))\n","(n, m) = list(map(int, input().split()))\nboard_size = n * m\nnum = 0\nif n % 2 == 0 or m % 2 == 0:\n\tnum = board_size / 2\nelif n == 1 and m == 1:\n\tnum = 0\nelse:\n\tnum = (board_size - 1) / 2\nprint(int(num))\n","m = input().split()\nnum1 = int(m[0])\nnum2 = int(m[1])\narea = num1 * num2\nprint(area // 2)\n","a = input()\nb = list(map(int, a.split()))\nM = b[0]\nN = b[1]\nif M % 2 == 0 or N % 2 == 0:\n\tprint(int(M * N / 2))\nelse:\n\tprint(int((M * N - 1) / 2))\n","from sys import stdin\ninput = stdin.readline\n(n, k) = map(int, input().split())\ndomino = n * k // 2\nprint(domino)\n","(n, m) = map(int, input().split())\nmax_side = max(m, n)\nmin_side = min(m, n)\nans = min_side * (max_side // 2)\nif max_side % 2 != 0:\n\tans += min_side // 2\nprint(ans)\n","(n, k) = map(int, input().split())\no = n * k\nprint(o // 2)\n","line1 = input()\nM = int(line1.split(' ')[0])\nN = int(line1.split(' ')[1])\nif M * N % 2 == 0 or M * N % 2 == 1:\n\tprint(int(M * N / 2))\n","(ms, s) = list(map(int, input().split()))\nprint(ms * s // 2)\n","def putDomino(tableLength, tableWidth):\n\twhile 1 <= tableLength <= tableWidth <= 16:\n\t\ttableSize = tableLength * tableWidth\n\t\tdominoMax = tableSize // 2\n\t\tprint(dominoMax)\n\t\tbreak\n(x, y) = map(int, input().split())\nputDomino(x, y)\n","string = input().split(' ')\nprint(int(int(int(string[0]) * int(string[1])) / 2))\n","s = input()\nm = []\nfor x in s.split():\n\tm.append(int(x))\nprint(m[0] * m[1] // 2)\n","domino = input()\ndomino_list = domino.split(' ')\ndomino_list = list(map(int, domino_list))\ndomino_list.sort()\n(M, N) = domino_list\nif N % 2 == 0:\n\tprint(int(M * (N / 2)))\nelif N % 2 == 1:\n\tprint(int(M * (N // 2) + M // 2))\n","(M, N) = map(int, input().split())\ns = M * N\no = s // 2\nprint(o)\n","(l, b) = list(map(int, input().split()))\nn1 = l // 2\ne1 = 0\ne2 = 0\nif l - 2 * n1 > 0:\n\te1 = 1\n\te2 = b // 2\nprint(n1 * b + e1 * e2)\n","import math\n(m, n) = input('').split(' ')\nm = int(m)\nn = int(n)\na = math.floor(m / 2)\nb = math.floor(n / 2)\nif m % 2 == 0:\n\tz = a * n\nelse:\n\tz = a * n + b\nprint(z)\n","arr = list(map(int, input().split()))\ncount = 0\nif arr[0] % 2 == 1:\n\tcount += arr[1] // 2\n\tarr[0] -= 1\ncount += arr[0] // 2 * arr[1]\nprint(count)\n","ch = input()\nl = ch.split(' ')\n(M, N) = (eval(l[0]), eval(l[-1]))\nprint(M * N // 2)\n","rec = [int(s) for s in input().split()]\nprint(rec[0] * rec[1] // 2)\n","import sys\nline = sys.stdin.readline().strip().split(' ')\na = int(line[0])\nb = int(line[1])\nprint(a * b // 2)\n","def max_dominos(n, m):\n\treturn n * m // 2\n(n, m) = map(int, input().split())\nprint(max_dominos(n, m))\n","a = list(map(int, input().split()))\narea = a[0] * a[1]\nnum = int(area / 2)\nprint(num)\n","import math\n(m, n) = input().split()\na = int(m)\nb = int(n)\nc = a * b\nd = c / 2\nprint(math.floor(d))\n","k = list(map(int, input().split()))\ns = k[0] * k[1] // 2\nprint(s)\n","def checkSize(s):\n\ttotalSquares = s[0] * s[1]\n\tprint(int(totalSquares / 2))\ns = list(map(int, input().split()))\ncheckSize(s)\n","length = input()\ntemp = length.split(' ')\nx = int(temp[0])\ny = int(temp[1])\narea = x * y\ndomino = int(area / 2)\nprint(domino)\n","m_n = input()\nx = m_n.split(' ')\nres = int(x[0]) * int(x[1]) / 2\nprint(int(res))\n","k = input().split(' ')\nprint(int(k[0]) * int(k[1]) // 2)\n","import sys\ns = sys.stdin.read()\nS = s.split()\nS = [int(i) for i in S]\na = S[0] * S[1]\nif a % 2 == 0:\n\tprint(int(a / 2))\nelse:\n\tprint(int((a - 1) / 2))\n","(length, width) = map(int, input().split())\nif length == 1 and width == 1:\n\tprint(0)\nelif length > width:\n\toutput = length // 2 * width + length % 2 * width / 2\n\toutput = int(output)\n\tprint(output)\nelse:\n\toutput = width // 2 * length + width % 2 * length / 2\n\toutput = int(output)\n\tprint(output)\n","def Main():\n\t(m, n) = [int(i) for i in input().split(' ')]\n\tif m * n % 2 == 0:\n\t\treturn m * n // 2\n\telse:\n\t\treturn m // 2 * n + n // 2\nprint(Main())\n","(M, N) = map(int, input().split())\nP = 2\nprint(int(M * N // P))\n","(m, n) = [int(x) for x in input().split()]\nprint(int(0.5 * m * n))\n","(x, y) = map(int, input().split())\nprint(round(x * y // 2))\n","dm = input().split()\nprint(int(dm[0]) * int(dm[1]) // 2)\n","import math\n(m, k) = map(int, input().split())\na = m * k\nif a % 2 == 0:\n\tprint(a // 2)\nelse:\n\tprint(math.floor(a / 2))\n","dimension = input()\nstring = dimension.split(' ')\narea = int(string[0]) * int(string[1])\nif area % 2 == 0:\n\tanswer = area // 2\n\tprint(answer)\nelse:\n\tanswer = (area - 1) // 2\n\tprint(answer)\n","n = list(map(int, input().split()))\n(M, N) = (n[0], n[1])\ns = M * N\nprint(int(s / 2))\n","inp = [int(x) for x in input().split()]\na = inp.pop(0)\nb = inp.pop(0)\nx = a * b\nhasil = x / 2\nprint(int(hasil))\n","a = [int(e) for e in input().split()]\nif a[0] * a[1] % 2 == 0:\n\tprint(int(a[0] * a[1] / 2))\nelse:\n\tprint(int((a[0] * a[1] - 1) / 2))\n","parameters = input().split()\n(m, n) = (int(parameters[0]), int(parameters[1]))\nresult = 0\nif m > 1 and n > 1:\n\tresult = m // 2 * (n // 2) * 2\n\tif m % 2 != 0 and n % 2 != 0:\n\t\tresult += n // 2 + m // 2\n\telif m % 2 != 0:\n\t\tresult += n // 2\n\telif n % 2 != 0:\n\t\tresult += m // 2\nelif m > 1:\n\tresult = m // 2\nelif n > 1:\n\tresult = n // 2\nprint(result)\n","mang = list(input().split())\ndominoes = int(mang[0]) * int(mang[1]) // 2\nprint(dominoes)\n","import math\n(M, N) = map(int, input().split())\nD = M * N / 2\nprint(math.floor(D))\n","(m, n) = [int(x) for x in input().split()]\ndominos = 2\nsol = 0\narea = m * n\nwhile dominos <= area:\n\tsol = sol + 1\n\tdominos = dominos + 2\nprint(sol)\n","a = input()\na = a.split()\nM = int(a[0])\nN = int(a[1])\nb = N * M\nc = b // 2\nprint(c)\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nnum_dominos = 0\nif n == m:\n\tif n > 3:\n\t\tif n % 2 == 0:\n\t\t\tfor i in range(int(n / 2)):\n\t\t\t\tnum_dominos += n\n\t\telse:\n\t\t\tfor i in range(n // 2):\n\t\t\t\tnum_dominos += n\n\t\t\tnum_dominos += n // 2\n\telif n > 2:\n\t\tnum_dominos += n\n\t\tnum_dominos += m % 2\n\telif n == 2:\n\t\tnum_dominos += n\n\telif n < 2:\n\t\tnum_dominos = 0\nelif n > m:\n\tnum_dominos += n\n\tif m > 3:\n\t\tif m % 2 == 0:\n\t\t\tfor i in range(m // 2 - 1):\n\t\t\t\tnum_dominos += n\n\t\telse:\n\t\t\tfor i in range(m // 2 - 1):\n\t\t\t\tnum_dominos += n\n\t\t\tnum_dominos += n // 2\n\telif m > 2:\n\t\tif n % 2 != 0:\n\t\t\tnum_dominos += n // 2\n\t\telif n % 2 == 0:\n\t\t\tnum_dominos += n // 2\n\telif m == 2:\n\t\tnum_dominos += 0\n\telif m == 1:\n\t\tnum_dominos -= n\n\t\tnum_dominos += n // 2\n\telif m <= 0:\n\t\tnum_dominos = 0\nelif m > n:\n\tnum_dominos += m\n\tif n > 3:\n\t\tif n % 2 == 0:\n\t\t\tfor i in range(n // 2 - 1):\n\t\t\t\tnum_dominos += m\n\t\telse:\n\t\t\tfor i in range(n // 2 - 1):\n\t\t\t\tnum_dominos += m\n\t\t\tnum_dominos += m // 2\n\telif n > 2:\n\t\tif m % 2 != 0:\n\t\t\tnum_dominos += m // 2\n\t\telif m % 2 == 0:\n\t\t\tnum_dominos += m // 2\n\telif n == 2:\n\t\tnum_dominos += 0\n\telif n == 1:\n\t\tnum_dominos -= m\n\t\tnum_dominos += m // 2\n\telif n <= 0:\n\t\tnum_dominos = 0\nprint(num_dominos)\n","inp = input()\nm = int(inp.split()[0])\nn = int(inp.split()[1])\nif m % 2 == 1 and n % 2 == 1:\n\tans = (m * n - 1) / 2\nelse:\n\tans = m * n / 2\nprint(int(ans))\n","(x, y) = map(int, input().split())\nxx = x // 2\nyy = y // 1\nsum1 = xx * yy\nif x - xx * 2 >= 1:\n\ty1 = y // 2\n\tsum1 = sum1 + y1 * 1\nprint(sum1)\n","x = input().split()\ntot = 1\nfor item in x:\n\ttot *= int(item)\nprint(tot // 2)\n","(m, n) = [int(x) for x in input().split()]\nboard_area = m * n\nprint(board_area // 2)\n","try:\n\t(a, b) = list(map(int, input().split()))\n\tc = a * b\n\td = c // 2\n\te = int(d)\n\tprint(e)\nexcept:\n\tpass\n","def main():\n\t(m, n) = [int(x) for x in input().split(' ')]\n\tarea = m * n\n\tif area % 2 == 0:\n\t\tdominos = area / 2\n\telse:\n\t\tdominos = (area - 1) / 2\n\tprint(int(dominos))\nmain()\n","(m, n) = input().split(' ')\ntotal_squares = int(m) * int(n)\nprint(int(total_squares / 2))\n","(square_size1, square_size2) = map(int, input().split())\nprint(int(square_size1 * square_size2 / 2))\n","(m, N) = map(int, input().split())\nprint(m * N // 2)\n","(m, n) = map(int, input().split())\na = m // 2\nb = n\nans = a * b\nempty = m % 2\nif empty == 1:\n\tans = ans + n // 2\nprint(ans)\n","import sys\n(n, m) = map(int, sys.stdin.readline().strip().split())\nprint(n * m // 2)\n","def f(a):\n\treturn int(a)\na = input().split()\na.sort(key=f)\nb = 0\nif int(a[0]) % 2 == 0:\n\tprint(int(a[0]) // 2 * int(a[1]))\nelse:\n\tb += int(a[0]) // 2 * int(a[1])\n\tprint(b + int(a[1]) // 2)\n","(m, n) = [int(i) for i in input().split()]\nkol = int(m / 2) * n\nif m % 2:\n\tkol += int(n / 2)\nprint(kol)\n","import math\n(m, n) = list(map(int, input().split()))\ne = m * n\nw = 2 * 1\nprint(e // w)\n","lines = input().split()\nn = int(lines[0])\nm = int(lines[1])\na = 0\nif n % 2 == 0 or m % 2 == 0:\n\ta = int(m * n / 2)\n\tprint(a)\nelif n == 1:\n\ta = int((m - 1) / 2)\n\tprint(a)\nelse:\n\ta = int((n - 1) * m / 2 + (m - 1) / 2)\n\tprint(a)\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nlop = True\ni = 1\nwhile lop == True:\n\tif m * n == 2 * i:\n\t\tprint(i)\n\t\tlop = False\n\telif m * n < 2 * i:\n\t\tprint(i - 1)\n\t\tlop = False\n\telse:\n\t\ti += 1\n","(m, n) = map(int, input().split())\nx = m % 2\nt = int(m / 2) * n\nif x == 1:\n\ts = t + int(n / 2)\nelse:\n\ts = t\nprint(int(s))\n","print(int(eval(input().replace(' ', '*')) / 2))\n","import random\nimport sys\nimport os\n(w, x) = input().split(' ')\nw = int(w)\nx = int(x)\nprint(w * x // 2)\n","def find_max_dominos(a, b):\n\tresult = int(a * b / 2)\n\treturn result\n(a, b) = map(int, input().split(' '))\nprint(find_max_dominos(a, b))\n","(x, y) = list(map(int, input().split()))\ntotal = print(int(x * y / 2 - 0.5 if x * y % 2 != 0 else x * y / 2))\n","board = [int(dim) for dim in input().split()]\narea = board[0] * board[1]\ndominos = 1\nwhile dominos * 2 <= area:\n\tdominos += 1\nprint(dominos - 1)\n","MN = input().split()\nM = int(MN[0])\nN = int(MN[1])\na = max(M, N)\nb = min(M, N)\nAll = 0\nwhile b >= 1:\n\th = b * int(a / 2)\n\tAll = All + h\n\tt = a\n\ta = max(a % 2, b)\n\tb = min(t % 2, b)\n\tif a == 1 and b == 1:\n\t\tbreak\nprint(All)\n","import math\n[M, N] = [int(s) for s in input().split(' ')]\nans = math.floor(M * N / 2)\nprint(ans)\n","a = input()\nb = a.split(' ')\nc = int(b[0])\nd = int(b[1])\nh = c * d\nk = h / 2\nif type(k) == int():\n\tk = k\nelse:\n\tk = int(k)\nprint(k)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nis_even = n % 2 == 0\nresult = n // 2 * m\nif not is_even:\n\tresult = result + m // 2\nprint(result)\n","import sys\ninput = sys.stdin.readline\n\ndef invr():\n\treturn list(map(int, input().split()))\ninput1 = invr()\nareaOFBoard = input1[0] * input1[1]\nareaOfDominoes = 2\nres = areaOFBoard // areaOfDominoes\nprint(res)\n","(m, n) = input().split()\nar1 = int(m) * int(n)\nar2 = 2 * 1\ni = 0\nwhile ar2 * i <= ar1:\n\tmaxm = i\n\ti = i + 1\nprint(maxm)\n","(x, y) = [int(a) for a in input().split()]\nz = x * y\nd = z // 2\nprint(d)\n","import sys\n\ndef int_split(target, delimiter=' '):\n\treturn [int(x) for x in target.split(delimiter)]\nMAX_SIZE = 16\n(m, n) = int_split(sys.stdin.readline())\nprint(m * n // 2)\n","input_data = input()\nlist_we_use = input_data.split(' ')\nm = []\nfor i in list_we_use:\n\tm.append(int(i))\nj = m[0] * m[1]\nprint(j // 2)\n","(n, m) = list(map(int, input().split()))\nnum = n // 2 * m\nif n % 2 == 1:\n\tnum += m // 2\nprint(num)\n","input_s = input()\ninput_list = input_s.split(' ')\nm = int(input_list[0])\nn = int(input_list[1])\nresult = m // 2 * n + m % 2 * (n // 2)\nprint(result)\n","ein = input('')\neing = ein.split(' ')\na = int(eing[0])\nb = int(eing[-1])\nprint(a * b // 2)\n","(m, n) = input().split()\nreq = int(m) * int(n)\ncount = 0\nwhile req - 2 > -1:\n\tcount += 1\n\treq -= 2\nprint(count)\n","import sys\n\ndef gets():\n\treturn sys.stdin.readline().strip()\n\ndef get():\n\treturn int(sys.stdin.readline().strip())\n\ndef geti():\n\treturn map(int, sys.stdin.readline().strip().split())\n\ndef getli():\n\treturn list(map(int, sys.stdin.readline().strip().split()))\n(m, n) = geti()\nprint(m * n // 2)\n","(n, m) = [int(i) for i in input().split(' ')]\nif not n % 2 or not m % 2:\n\tif not n % 2:\n\t\tprint(int(n / 2) * m)\n\telse:\n\t\tprint(int(m / 2) * n)\nelse:\n\tif n < m:\n\t\t(n, m) = (m, n)\n\tprint(int(n / 2) * m + int(m / 2))\n","board_size = input().split()\nM = int(board_size[0])\nN = int(board_size[1])\nif M % 2 == 0 and N % 2 == 0 or (M % 2 != 0 and N % 2 == 0):\n\tprint(N // 2 * M)\nelif M % 2 == 0 and N % 2 != 0:\n\tprint(M // 2 * N)\nelif M % 2 != 0 and N % 2 != 0:\n\tprint(M * N // 2)\n","from sys import stdin, stdout\nfrom math import floor\n\ndef main():\n\t(m, n) = [int(i) for i in stdin.readline().split()]\n\tstdout.write(str(floor(m * n / 2)) + '\\n')\nmain()\n","import os\n(m, n) = list(map(int, input().rstrip().split()))\nprint(m * n // 2)\n","(m, n) = list(map(int, input().rstrip().split()))\nbor = m * n\nprint(bor // 2)\n","from math import ceil\nq = input().split(' ')\nm = int(q[0])\nn = int(q[1])\nanswer = m * n // 2\nprint(answer)\n","a = input()\n(w, h) = list(map(int, str(a).split(' ')))\nif w % 2 == 1 and h % 2 == 1:\n\tprint(int((w - 1) * h / 2) + int((h - 1) / 2))\nelse:\n\tprint(int(w * h / 2))\n","board_sides = list(map(int, input().split()))\nif 1 <= board_sides[0] <= board_sides[1] <= 16:\n\toutput = board_sides[0] * board_sides[1] // 2\n\tprint(output)\n","l = list(map(int, input().split(' ')))\nM = l[0]\nN = l[1]\nprint(int(M * N / 2))\n","def solve(m, n):\n\ttileArea = 2 * 1\n\tborderArea = m * n\n\treturn int(borderArea / tileArea)\n(m, n) = map(int, input().split())\nprint(solve(m, n))\n","(m, n) = [int(i) for i in input().split(' ')]\nd = m * (n // 2) + n % 2 * (m // 2)\nprint(d)\n","class CodeforcesTask50ASolution:\n\n\tdef __init__(self):\n\t\tself.result = ''\n\t\tself.size = []\n\n\tdef read_input(self):\n\t\tself.size = [int(x) for x in input().split(' ')]\n\n\tdef process_task(self):\n\t\tself.result = str(self.size[0] * self.size[1] // 2)\n\n\tdef get_result(self):\n\t\treturn self.result\nSolution = CodeforcesTask50ASolution()\nSolution.read_input()\nSolution.process_task()\nprint(Solution.get_result())\n","from sys import stdin\nm = list(map(int, stdin.readline().strip().split()))\na = m[0]\nb = m[1]\nprint(a * b // 2)\n","from math import floor\n(N, K) = [int(x) for x in input().strip().split(' ')]\nprint(floor(N * K / 2))\n","def main():\n\tline = input()\n\tarray = line.split(' ')\n\tm = int(array[0])\n\tn = int(array[1])\n\tprint(int(m * n / 2))\nmain()\n","(m, n) = map(int, input().split())\nd = m // 2 * n\nif m % 2 == 1:\n\td += n // 2\nprint(d)\n","(n, m) = map(int, input().split())\nif n % 2 == 0 and m % 2 == 0:\n\tsol = int(n * m / 2)\n\tprint(sol)\nelif n % 2 == 0 and m % 2 != 0:\n\tsol = int(n / 2 * m)\n\tprint(sol)\nelif n % 2 != 0 and m % 2 == 0:\n\tsol = int(m / 2 * n)\n\tprint(sol)\nelse:\n\tsol = (n * m - 1) / 2\n\tsols = int(sol)\n\tprint(sols)\n","(m, n) = [int(i) for i in input().split()]\nx = m * n\ny = 2 * 1\nprint(x // y)\n","count = 1\nboard = input()\nboardlist = board.split(' ')\nfor i in boardlist:\n\tcount *= int(i)\nprint(count // 2)\n","import math\nx = input().split()\nm = int(x[0])\nn = int(x[1])\ny = m * n\nresult = math.floor(y / 2)\nprint(result)\n","(m, n) = map(int, input().split(' '))\nprint((str(int(n * m / 2)), str(m * int(n / 2) + int(m / 2)))[n * m % 2 != 0])\n","(h, w) = map(int, input().split())\nprint(h * w // 2)\n","pieces = input().split()\na = int(pieces[0])\nb = int(pieces[1])\nn = a * b // 2\nprint(n)\n","def howManyDominos(N, M):\n\treturn N * M // 2\n(N, M) = [int(i) for i in input().split()]\nprint(howManyDominos(N, M))\n","from math import floor\na = list(map(int, input().split()))\nx = floor(a[0] * a[1] / 2)\nprint(x)\n","(m, n) = map(int, input().split())\na = m * n\nsum = 0\nwhile a > 0:\n\ta = a - 2\n\tif a >= 0:\n\t\tsum = sum + 1\nprint(sum)\n","def Domino_piling(M, N):\n\tboard_size = M * N\n\tpieces = 2 * 1\n\tmaximal_number_of_dominoes = board_size // pieces\n\tprint(maximal_number_of_dominoes)\n(M, N) = map(int, input().split())\nDomino_piling(M, N)\n","import math\nboard_size_inputs = input()\nlength = int(board_size_inputs.split(' ')[0])\nbreadth = int(board_size_inputs.split(' ')[1])\nboard_size = length * breadth\nsquares = math.floor(board_size / 2)\nprint(squares)\n","a = input()\na = a.split(' ')\nm = int(a[0])\nn = int(a[1])\nsq = m * n\ndom = sq / 2\nprint('%d' % dom)\n","import math\n(m, n) = input().split()\n(m, n) = [int(m), int(n)]\ntotal_area = m * n\ndominos = math.floor(m * n / 2)\nprint(dominos)\n","strs = input()\nstrs = strs.split(' ')\nn = int(strs[0])\nm = int(strs[1])\nprint(int(n * m / 2))\n","import sys\ni = list(map(int, sys.stdin.readlines()[0].split()))\na = i[0] // 2 * i[1]\nif i[0] % 2 != 0:\n\ta += i[1] // 2\nprint(a)\n","def Main():\n\t(m, n) = map(int, input().split(' '))\n\tval = m * n\n\tcnt = int(val / 2)\n\tprint(cnt)\nMain()\n","(m, n) = map(int, input().split())\nboard = m * n\nTd = 2\nnumber_of_dominos = board // Td\nprint(number_of_dominos)\n","s = str(input())\nj = list(map(int, s.split(' ')))\nM = int(j[0])\nN = int(j[-1])\nif M % 2 == 0 or N % 2 == 0:\n\tw = M * N / 2\nelse:\n\tw = (M * N - 1) / 2\nprint(int(w))\n","(A, B) = input().split()\n(a, b) = (int(A), int(B))\nn = int(a * b / 2)\nprint(n)\n","import sys\nimport math\nimport os\n(n, m) = map(int, input().split())\nprint(int(m * n / 2))\n","import math\n\ndef function(arr, k):\n\tprint(math.floor(m * n / 2))\nl = list(map(int, input().rstrip().split()))\nm = l[0]\nn = l[1]\nfunction(m, n)\n","num_array = input().split()\nnum1 = int(num_array[0])\nnum2 = int(num_array[1])\nprint(int(num1 * num2 / 2))\n","(m, n) = map(int, input().split())\nta = 2 * 1\nba = m * n\nprint(int(ba / ta))\n","a = str(input())\ns = a.split(' ')\nn = int(s[0])\nm = int(s[1])\nprint(n // 2 * m + m // 2 * (n % 2))\n","n = input().split()\nif int(n[0]) * int(n[1]) / 2 == 0:\n\tPrint(int(n[0]) * int(n[1]) / 2)\nelse:\n\tprint(int(int(n[0]) * int(n[1]) / 2))\n","sq = input().split()\nsize = int(sq[0]) * int(sq[1])\nprint(size // 2)\n","def coverBoard(m, n):\n\treturn m * n // 2\n(m, n) = input().split(' ')\nprint(coverBoard(int(m), int(n)))\n","(n, m) = map(int, input().split())\nd = n * m\nt = d // 2\nprint(t)\n","s = input()\n(n, m) = s.split()\nn = int(n)\nm = int(m)\nif (n % 2 == 0) | (m % 2 == 0):\n\tprint(n * m // 2)\n\texit()\nprint((n * m - 1) // 2)\n","def program():\n\tpass\n(width, height) = list(map(int, input().strip().split()))\nsize = width * height\nprint(size // 2)\n","def list_input():\n\treturn list(map(int, input().split()))\n\ndef multiple_input():\n\treturn map(int, input().split())\n(a, b) = multiple_input()\nans = a * b\nprint(ans // 2)\n","s = input()\n(m, n) = s.split()\nm = int(m)\nn = int(n)\nb = m * n\na = b // 2\nprint(a)\n","params = [int(i) for i in input().split()]\narea = params[0] * params[1]\ndominos = area // 2\nprint(dominos)\n","def solve(m, n):\n\treturn m * n // 2\n(m, n) = list(map(int, input().split()))\nprint(solve(m, n))\n","MN = input().split()\nS = int(MN[0]) * int(MN[1])\nprint(S // 2)\n","boardSizeList = list(map(int, input().split()))\nm = boardSizeList[0]\nn = boardSizeList[1]\nboardSize = m * n\nif boardSize % 2 == 1:\n\tusableSpace = boardSize - 1\nelse:\n\tusableSpace = boardSize\nanswer = int(usableSpace / 2)\nprint(answer)\n","job = input().split()\n(m, n) = (int(job[0]), int(job[1]))\nprint(int(m * n / 2))\n","a = []\ntt = str()\nb = []\ns = str(input()).replace(' ', ',')\nfor i in range(len(s)):\n\tif s[i] != ',':\n\t\ttt = tt + s[i]\n\telse:\n\t\ta.append(tt)\n\t\ttt = ''\na.append(tt)\nfor i in a:\n\tif i != ',':\n\t\tb.append(i)\nsun = int(b[0]) * int(b[1])\nif sun == 1:\n\tout = 0\nelse:\n\tout = sun // 2\nprint(out)\n","(n, m) = map(int, input().strip().split(' '))\nif m == 0 or n == 0:\n\tprint(min(m, n))\nelif m == 1 or n == 1:\n\tprint(max(m, n) // 2)\nelif min(m, n) % 2 == 0:\n\tprint(max(m, n) * (min(m, n) // 2))\nelse:\n\tprint(max(m, n) * (min(m, n) // 2) + max(m, n) // 2)\n","A = str(input())\n(a, b) = A.split()\na = int(a)\nb = int(b)\nx = b // 2\nif b % 2 == 1:\n\ty = a // 2\n\tanswer = x * a + y\nelse:\n\tanswer = x * a\nprint(answer)\n","import math\n(M, N) = map(int, input().split())\nnum_of_squares = M * N\nans = math.floor(num_of_squares * 0.5)\nprint(ans)\n","def read_numbers():\n\treturn [int(x) for x in input().split()]\n(x, y) = read_numbers()\nk = x * y\nl = k // 2\nprint(l)\n","lis = list(map(int, input().split()))\narea = lis[0] * lis[1]\nprint(area // 2)\n","lst = [int(x) for x in input().split()]\nm = lst[0]\nn = lst[1]\noverall = 0\nprint(m * n // 2)\n","import math\n(x, y) = map(int, input().split())\nif x % 2 != 0 and y % 2 != 0:\n\tres = math.floor(y / 2) * x + math.floor(x / 2)\n\tprint(res)\nelif x % 2 == 0 and y % 2 == 0:\n\tres = x * y // 2\n\tprint(res)\nelse:\n\tres = x * y // 2\n\tprint(res)\n","(a, b) = [int(x) for x in input('').split()]\na_e = a % 2 == 0\nb_e = b % 2 == 0\nif a_e | b_e:\n\tres = a * b / 2\nelse:\n\tres = (a * b - 1) / 2\nprint(int(res))\n","def checkSide(bigger, lesser):\n\tv1 = bigger / 2\n\tv2 = lesser\n\treturn int(v1 * v2)\ninp = input().split()\nboardSize = int(inp[0]) * int(inp[1])\nresult = list(map(int, inp))\nresult.sort()\nbigger = int(inp[1])\nlesser = int(inp[0])\nprint(checkSide(bigger, lesser))\n","x = input()\nxx = x.split()\nm = int(xx[0])\nn = int(xx[1])\ntend = int(0)\n\ndef eveneven():\n\ttend = int(m / 2) * int(n / 1)\n\tprint(int(tend))\n\treturn\n\ndef evenodd():\n\ttend = int(m / 2) * int(n / 1)\n\tprint(int(tend))\n\treturn\n\ndef oddeven():\n\ttend = int(m / 1) * int(n / 2)\n\tprint(int(tend))\n\treturn\n\ndef oddodd():\n\ttend = (n * m - 1) / 2\n\tprint(int(tend))\n\treturn\nif m == 1 and n == 1:\n\tprint('0')\nelif m == 3 and n == 3:\n\tprint('4')\nelif m % 2 == 0 and n % 2 == 0:\n\teveneven()\nelif m % 2 == 0 and n % 2 == 1:\n\tevenodd()\nelif m % 2 == 1 and n % 2 == 0:\n\toddeven()\nelif m % 2 == 1 and n % 2 == 1:\n\toddodd()\n","def main():\n\t(board_width, board_height) = map(int, input().split())\n\t(dominos_x, dominos_y, dominos_extra) = (0, 0, 0)\n\tif board_width > 1:\n\t\tdominos_x = int(board_width / 2)\n\t\tdominos_y = board_height\n\t\tif board_width % 2 == 1:\n\t\t\tdominos_extra = int(board_height / 2)\n\telif board_height > board_width:\n\t\tdominos_x = 1\n\t\tdominos_y = int(board_height / 2)\n\ttotal_dominos = dominos_x * dominos_y + dominos_extra\n\tprint(total_dominos)\nmain()\n","mn = list(input().split())\nm = int(mn[0])\nn = int(mn[1])\ncount = 0\nif m % 2 == 0 and n % 2 == 0:\n\tcount = int(n * m / 2)\nif m % 2 == 0 and n % 2 != 0:\n\tcount = int((n - 1) * m / 2 + int(m / 2))\nif m % 2 != 0 and n % 2 == 0:\n\tcount = int((m - 1) * n / 2 + int(n / 2))\nelse:\n\tcount = int((m - 1) * (n - 1) / 2 + int(n / 2) + int(m / 2))\nprint(count)\n","l = [int(x) for x in input().split()]\n(n, m) = (l[0], l[1])\nmn = min(n, m)\nmx = max(n, m)\nprint(mn // 2 * mx + mn % 2 * (mx // 2))\n","(n, m) = list(map(int, input().split()))\nx = n * m\nif x % 2 is 1:\n\tx -= 1\nans = x / 2\nprint(int(ans))\n","(a, b) = map(int, input().split())\nprint(a * b // 2)\nexit(0)\n","import math as math\nstring = input().split(' ')\nm = int(string[0])\nn = int(string[1])\nprint(math.floor(m * n / 2))\n","(M, N) = map(int, input().split())\ntotal_squares = M * N\ndominoes = total_squares // 2\nprint(dominoes)\n","(m, n) = input().split()\nM = int(m)\nN = int(n)\nnum = M * N // 2\nprint(num)\n","(s, m) = map(int, input().split())\nprint(s * m // 2)\n","(w1, w2) = input().split()\nm = int(w1)\nn = int(w2)\nmaxdominos = m * n // 2\nprint(maxdominos)\n","(M, N) = list(map(int, input().split()))\nsize = M * N\ntotal = size // 2\nprint(total)\n","(m, n) = map(int, input().split())\nz = m * n\nnum = m * n / 2\nprint(int(num))\n","x = input('')\ne = x.split(' ')\nd = float(e[0]) * float(e[1])\nf = (d - d % 2) / 2\nprint(int(f))\n","(M, N) = list(map(int, input().split()))\ns0 = M * N\nr = s0 % 2\nprint(int((s0 - r) / 2))\n","(m, n) = [int(x) for x in input().split()]\na1 = m * n\nprint(a1 // 2)\n","(m, n) = map(int, input().split())\nx = m // 2\ny = n // 2\nans1 = x * n + (m - 2 * x) * y\nans2 = y * m + (n - 2 * y) * x\nprint(max(ans1, ans2))\n","import math\n\nclass P50A:\n\n\tdef __init__(self):\n\t\tself.board_width = None\n\t\tself.board_height = None\n\t\tself.solution = None\n\n\tdef parse_input(self):\n\t\t(self.board_width, self.board_height) = (int(i) for i in input().split())\n\n\tdef solve(self):\n\t\tself.solution = math.floor(self.board_height * self.board_width / 2)\n\n\tdef get_solution(self):\n\t\treturn self.solution\np_50A = P50A()\np_50A.parse_input()\np_50A.solve()\nprint(p_50A.get_solution())\n","a = input()\nb = a.split()\nc = int(b[0])\nd = int(b[1])\ne = c * d // 2\nprint(e)\n","import math\n\ndef solution():\n\t(m, n) = [int(x) for x in input().split()]\n\tp = math.floor(m / 2)\n\tq = math.floor(n / 2)\n\ts = 2 * p * q\n\tif m % 2 == 1 and n % 2 == 1:\n\t\ts += p + q\n\telif m % 2 == 1 and n % 2 == 0:\n\t\ts += q\n\telif m % 2 == 0 and n % 2 == 1:\n\t\ts += p\n\tprint(s)\nsolution()\n","g = lambda : map(int, input().split())\n(m, n) = g()\nprint(n * m // 2)\n","import math\n(m, n) = [int(x) for x in input().split()]\ns = m * n\nnumber = math.floor(s / 2)\nprint(number)\n","import sys\ninput = sys.stdin.readline\n\ndef main():\n\ti = inlt()\n\tans = int(i[0] / 2) * i[1]\n\tif i[0] % 2 == 1:\n\t\tans += int(i[1] / 2)\n\tprint(ans)\n\ndef inp():\n\treturn int(input())\n\ndef inlt():\n\treturn list(map(int, input().split()))\n\ndef instr():\n\treturn ''.join(insr())\n\ndef insr():\n\ts = input()\n\treturn list(s[:len(s) - 1])\n\ndef invr():\n\treturn map(int, input().split())\nmain()\n","a = [int(s) for s in input().split()]\nr = a[0] * a[1]\nr = int(r)\nn = 0\nn = int(n)\nwhile r > 1:\n\tr -= 2\n\tn += 1\nprint(n)\n","(n, k) = tuple(map(int, input().split()))\nprint(n * k // 2)\n","(m, n) = map(int, input().split(' '))\ntile_area = 2 * 1\nboard_area = m * n\nprint(int(board_area / tile_area))\n","(n, m) = map(int, input().split())\nif n & 1 and m & 1:\n\tprint(n * m - 1 >> 1)\nelse:\n\tprint(n * m >> 1)\n","a = input()\n(c, d) = map(int, a.split())\nf = c * d\ng = f // 2\nprint(g)\n","from sys import stdin\n(m, n) = map(int, input().split())\nprint(m * n // 2)\n","i = lambda : map(int, input().split())\n(m, n) = i()\nprint([int(m * n / 2), 0][m == 1 and n == 1])\n","L = 2\nB = 1\n\ndef dominoes(row, col, l=L, b=B):\n\tarea = row * col\n\tarea_domino = L * b\n\tnum = area // area_domino\n\treturn num\n(row, col) = [int(x) for x in input().split()]\nnum = dominoes(row, col)\nprint(num)\n","(n, k) = map(int, input().split())\nb = n * k\nresult = int(b / 2)\nprint(result)\n","(M, n) = map(int, input().split())\nArea = M * n\nDomino = 2\nprint(Area // Domino)\n","(m, n) = input().split()\nprod = int(m) * int(n)\nprint(prod // 2)\n","s = input()\nk = []\nk = s.split(' ')\n(m, n) = (int(k[0]), int(k[1]))\narea = m * n\nn = area // 2\nprint(n)\n","def convert(string):\n\treturn string.split(sep=None, maxsplit=-1)\ns = convert(input())\nM = int(s[0])\nN = int(s[1])\nprint(M * N // 2)\n","import math\n(M, N) = map(int, input().split())\nnum = math.floor(M * N / 2)\nprint(num)\n","nm = input()\nnm = nm.split(' ')\nn = int(nm[0])\nm = int(nm[1])\nd = 2\nf = 0\nif n == 1 and m == 1:\n\tprint('0')\nelse:\n\tif n % 2 == 0:\n\t\trow = n // 2\n\t\tf = row * m\n\telse:\n\t\trow = n // 2\n\t\tf = row * m\n\t\tcol = m // 2\n\t\tf = f + col\n\tprint(f)\n","(longueur, largeur) = map(int, input().split())\nair = longueur * largeur\nresultat = int(air / 2)\nprint(resultat)\n","(n, m) = list(map(int, input().split()))\nimport math\nb = n * m\nif b % 2 == 0:\n\tprint(int(n * m / 2))\nelse:\n\ta = math.ceil(int(b / 2))\n\tprint(a)\n","wymiary = input()\nxy = wymiary.split(' ')\nx = int(xy[0])\ny = int(xy[1])\npolePlanszy = x * y\ndomino = polePlanszy / 2\nif domino % 1 == 0.5:\n\tdomino = domino - 0.5\ndomino = int(domino)\nprint(f'{domino}')\n","str1 = input()\nlist1 = str1.split(' ')\nM = int(list1[0])\nN = int(list1[1])\nnum1 = N // 2\nif not N % 2:\n\tmaxnum = M * num1\nelse:\n\tmaxnum = M * num1 + M // 2\nprint(maxnum)\n","import math\n(M, N) = map(int, input().split())\nb = M * N\nif b % 2 == 0:\n\tprint(b // 2)\nelse:\n\tk = math.floor(b // 2)\n\tprint(k)\n","import sys\nimport math\n(a, b) = map(int, sys.stdin.readline().split())\nprint(math.floor(int(a) * int(b) / 2))\n","nums = [int(x) for x in input().split()]\nprint(nums[0] * nums[1] // 2)\n","inp = input()\ntheLst = inp.split()\nm = int(theLst[0])\nn = int(theLst[1])\ndefault = 2\narea = m * n\nif area % 2 == 0:\n\tprint(int(area / default))\nelse:\n\tprint(int((area - 1) / default))\n","def area(m, n):\n\tarea = m * n\n\tresult = int(area / 2)\n\treturn result\nm_n = input()\nm_n_list = m_n.split()\nfor i in range(0, len(m_n_list)):\n\tm_n_list[i] = int(m_n_list[i])\ndominoes = area(m_n_list[0], m_n_list[1])\nprint(dominoes)\n","(m, n) = map(int, input().split())\nadd = 0\nif m % 2 != 0:\n\tif n % 2 == 0:\n\t\tt = m\n\t\tm = n\n\t\tn = t\n\telse:\n\t\tadd = int(n / 2)\n\t\tm = m - 1\nans = int(m * n / 2 + add)\nprint(ans)\n","(M, N) = map(int, input().split())\nsize = M * N\ndominoes = size // 2\nprint(dominoes)\n","import sys, itertools, math\n\ndef ia():\n\treturn [int(i) for i in sys.stdin.readline().strip().split(' ')]\n\ndef ii():\n\treturn int(sys.stdin.readline().strip())\n(m, n) = ia()\nprint(m * n // 2)\n","data = list(map(int, input().split()))\nif data[0] % 2 == 0:\n\tcant = data[0] / 2 * data[1]\nelif data[1] % 2 == 0:\n\tcant = data[1] / 2 * data[0]\nelif data[0] > data[1]:\n\tcant = int((data[0] - 1) / 2 * data[1] + (data[1] - 1) / 2)\nelse:\n\tcant = int((data[1] - 1) / 2 * data[0] + (data[0] - 1) / 2)\nprint(int(cant))\n","(m, n) = [int(i) for i in input().split()]\nboard = [[0 for _ in range(n)] for i in range(m)]\n\ndef pilling(matrix):\n\tdomino = 0\n\tfor i in range(len(matrix)):\n\t\tfor j in range(len(matrix[0]) - 1):\n\t\t\tif matrix[i][j] == matrix[i][j + 1] == 0:\n\t\t\t\tdomino += 1\n\t\t\t\tmatrix[i][j] = 1\n\t\t\t\tmatrix[i][j + 1] = 1\n\tfor i in range(len(matrix) - 1):\n\t\tfor j in range(len(matrix[0])):\n\t\t\tif matrix[i][j] == matrix[i + 1][j] == 0:\n\t\t\t\tdomino += 1\n\t\t\t\tmatrix[i][j] = 1\n\t\t\t\tmatrix[i + 1][j] = 1\n\treturn domino\nprint(pilling(board))\n","string = input('')\n(m, n) = string.split(' ')\ncount = int(m) * int(n)\nresult = count // 2\nprint(result)\n","import sys\nlocal_launch = False\ntry:\n\topen('LOCAL').read()\n\tlocal_launch = True\nexcept:\n\tpass\ninput_data = open('INPUT.txt').read() if local_launch else sys.stdin.read()\ndone = {'i': 0}\ntokens = input_data.split()\n\ndef next_token():\n\tresult = tokens[done['i']]\n\tdone['i'] += 1\n\treturn result\n\ndef next_int():\n\treturn int(next_token())\n\ndef next_str():\n\treturn next_token()\nm = next_int()\nn = next_int()\nu = m * n\nif u % 2 == 0:\n\tu = u // 2\n\tprint(u)\nelse:\n\tu = (u - 1) // 2\n\tprint(u)\n","inp = input().split()\nn = int(inp[0])\nm = int(inp[1])\ns = 0\nif n % 2 == 0 and m % 2 == 0:\n\ts = n * m / 2\nelif n % 2 == 1 and m % 2 == 0:\n\tk = n\n\tn = m\n\tm = k\nif m == 1:\n\ts = int(n / 2)\nif s == 0:\n\tk = 0\n\tif n % 2 == 1:\n\t\tk = 1\n\t\tn -= 1\n\tm -= 1\n\ts = n * m / 2\n\ts += n / 2\n\tif k:\n\t\ts += m / 2\nprint(int(s))\n","import math\na = []\nc = 0\nb = 0\n(n, m) = map(int, input().split())\nc = int(n / 2) * m\nif n % 2 != 0:\n\tc += int(m / 2)\nprint(c)\n","(M, N) = input().split()\nM_integer = int(M)\nN_integer = int(N)\ntotal_area = M_integer * N_integer\nnumber_dominoes = int(total_area / 2)\nprint(number_dominoes)\n","(n, m) = sorted([int(_) for _ in input().split()])\nif n % 2 == 1 and m % 2 == 1:\n\tprint(m * (n // 2) + m // 2)\nelif n % 2 == 0:\n\tprint(m * (n // 2))\nelse:\n\tprint(n * (m // 2))\n","k = input().split()\nM = int(k[0])\nN = int(k[1])\nk = M * N // 2\nprint(k)\n","A = input().split(' ')\nflaeche = 1\nfor i in range(2):\n\tA[i] = int(A[i])\n\tflaeche *= A[i]\nanzahl_dominos = int(flaeche / 2)\nprint(anzahl_dominos)\n","import math\nstring = input()\narr = string.split(' ')\narea = int(arr[0]) * int(arr[1])\nprint(int(math.floor(area / 2)))\n","import math\n(a, b) = input().split()\na = int(a)\nb = int(b)\nv1 = a * b\nprint(int(v1 / 2))\n","E = input().split()\nM = int(E[0])\nN = int(E[1])\nprint(M * N // 2)\n","x = input()\nx = x.split()\ny = int(x[0])\nz = int(x[1])\nq = y // 2\nw = y % 2\ne = w * z // 2\nres = q * z + e\nprint(res)\n","(m, n) = map(int, input().split())\nboard = m * n\ndomino = 2 * 1\nprint(board // domino)\n","(x, y) = [int(j) for j in input().split(' ')]\nprint(int(x * y / 2))\n","(a, b) = input().split(' ')\n(a, b) = (int(a), int(b))\nm = a * b\nc = 0\nn = 0\nwhile n <= m:\n\tn += 2\n\tc += 1\nprint(c - 1)\n","(n, m) = map(int, input().split())\nz = n * m\nif z % 2 == 0:\n\tnumber_of_dom = int(z / 2)\nelif z % 2 != 0:\n\tnumber_of_dom = int((z - 1) / 2)\nprint(number_of_dom)\n","try:\n\t(a, b) = map(int, input().split())\n\tprint(a * b // 2)\nexcept:\n\tpass\n","inp = str(input())\ninp = inp.split()\ninp[0] = int(inp[0])\ninp[1] = int(inp[1])\narea = inp[0] * inp[1]\nprint(area // 2)\n","class a:\n\n\tdef get(k, m, n):\n\t\tif not n % 2:\n\t\t\treturn m * (n // 2)\n\t\telif m % 2 == 0 and n % 2 != 0:\n\t\t\treturn m // 2 * n\n\t\telse:\n\t\t\treturn m * n // 2\nb = a()\n(m, n) = map(int, input().split())\nprint(b.get(m, n))\n","import math\n(l, w) = map(int, input().split())\nif l % 2 == 0:\n\tprint(int(l * w / 2))\nelse:\n\tl = l - 1\n\tm = int(l * w / 2)\n\tprint(m + math.floor(w / 2))\n","def floor(x: float) -> int:\n\n\tdef abs(y: float) -> float:\n\t\tif y < 0:\n\t\t\treturn y * -1\n\t\telse:\n\t\t\treturn y\n\treturn int(x - abs(x - int(x)))\n(M, N) = [int(x) for x in input().split()]\nprint(floor(M * N / 2))\n","str1 = input()\nlist1 = str1.split(' ')\nn = int(int(list1[0]) * int(list1[1]) / 2)\nprint(n)\n","(n, m) = [int(x) for x in input().split()]\nc = int(n / 2)\nrem = n % 2\nc *= m\nif rem == 0:\n\tprint(c)\nelse:\n\tcount = int(m / 2)\n\tc += count\n\tprint(c)\n","from sys import stdin\n\ndef isSquare(n, m):\n\tif n % 2 == 0 and m % 2 == 0:\n\t\treturn True\n\ndef count(n, m):\n\tif isSquare(n, m):\n\t\treturn int(n * m / 2)\n\tif n == 1 and m != 1:\n\t\treturn int(m / 2)\n\tif m == 1 and n != 1:\n\t\treturn int(n / 2)\n\telif n % 2 == 0 and m % 2 != 0:\n\t\treturn int(n * (m - 1) / 2 + n // 2)\n\telif n % 2 != 0 and m % 2 == 0:\n\t\treturn int(m * (n - 1) / 2 + m // 2)\n\telif n % 2 != 0 and m % 2 != 0:\n\t\treturn int((n - 1) * (m - 1) / 2 + n // 2 + (m - 1) // 2)\narr = str(stdin.readline()).replace('\\n', '').split(' ')\nprint(count(int(arr[0]), int(arr[1])))\n","(x, y) = [int(a) for a in input().split()]\nk = x * y\nl = k // 2\nprint(l)\n","(n, m) = list(map(int, input().rstrip().split()))\ntotal = m * n\nprint(total // 2)\n","l = input()\np = l.split()\nm = int(p[0])\nn = int(p[1])\ns = m * n\nans = int(s / 2)\nprint(ans)\n","(m, n) = map(int, input().split(' '))\na = m * n\nif a % 2 == 1:\n\ta -= 1\nprint(int(a / 2))\n","(m, n) = map(int, input().split(' '))\nnumber_squares = m * n\nif m > n:\n\tbigger_number = m\n\tsmaller_number = n\nelse:\n\tbigger_number = n\n\tsmaller_number = m\ndom = 0\nif number_squares % 2 == 0:\n\tdom = bigger_number / 2 * smaller_number\nelif number_squares % 2 == 1:\n\tfor i in range(1, bigger_number):\n\t\tif (number_squares - i) % 2 == 0:\n\t\t\tdom = (number_squares - i) / 2\n\t\tbreak\nprint(int(dom))\n","import sys\n(m, n) = map(int, sys.stdin.readline().split())\nif m == 1 and n == 1:\n\tprint(0)\n\tsys.exit(0)\ncount = m * n // 2\nprint(count)\n","def no_of_dodo(x, y):\n\treturn int(int(x) * int(y) / 2)\ninp = input().split()\nans = no_of_dodo(inp[0], inp[1])\nprint(ans)\n","def func():\n\tx = input().split()\n\tif int(x[1]) * int(x[0]) % 2 == 0:\n\t\tprint(int(int(x[1]) * int(x[0]) / 2))\n\telse:\n\t\tprint(int((int(x[1]) * int(x[0]) - 1) / 2))\nfunc()\n","x = input()\nf = ''\np = 0\nwhile p < len(x) and x[p] != ' ':\n\tf += x[p]\n\tp += 1\nM = int(f)\nN = int(x[len(f) + 1:len(x)])\nif M % 2 != 0 and N % 2 != 0:\n\tres = (M * N - 1) // 2\nelse:\n\tres = M * N // 2\nprint(res)\n","num = input()\nlist = num.split()\nm = int(list[0])\nn = int(list[1])\nif m % 2 != 0 and n % 2 != 0:\n\tw = (m * n - 1) / 2\nelse:\n\tw = m * n / 2\nprint(int(w))\n","s = input()\nl = s.split()\na = int(l[0])\nb = int(l[1])\nprint(a * b // 2)\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\nprint(math.ceil(m * n // 2))\n","Dominos = input()\n(M, N) = Dominos.split(' ')\nM = int(M)\nN = int(N)\n\ndef MaxDom(L, W):\n\tDomL = L // 2\n\tDomW = W // 2\n\tDomNoL = 0\n\tDonNoW = 0\n\tOutput = 0\n\tif L % 2 == 0:\n\t\tDomNoL = DomL * W\n\telif L % 2 > 0:\n\t\tDomNoL = DomL * W + DomW\n\tif W % 2 == 0:\n\t\tDomNoW = DomW * L\n\telif W % 2 > 0:\n\t\tDomNoW = DomW * L + DomL\n\tif DomNoL > DomNoW:\n\t\tOutput = DomNoL\n\t\treturn Output\n\telif DomNoW > DomNoW:\n\t\tOutput = DomNoW\n\t\treturn Output\n\telif DomNoW == DomNoW:\n\t\treturn DomNoW\nprint(MaxDom(M, N))\n","import math\n\ndef main():\n\tnum = input()\n\tl = list(num.split(' '))\n\tM = int(l[0])\n\tN = int(l[1])\n\tsum = M * N\n\tprint(math.floor(sum / 2))\nmain()\n","inputs = list(map(int, input().split(' ')))\nM = inputs[0]\nN = inputs[1]\namount = N * M // 2\nprint(str(amount))\n","(x, y) = tuple(input().split(' '))\nx = int(x)\ny = int(y)\nw = int(y / 2)\nsum = x * w\nif x % 2 == 1:\n\tx -= 1\nif y % 2 == 1:\n\tsum += x / 2\nprint(int(sum))\n","(x, y) = [int(x) for x in input().split()]\n(a, b) = (2, 1)\nif x >= a or y >= b:\n\tc = x * y // 2\n\tprint(c)\nelse:\n\tprint(0)\n","import sys\nnumbers = sys.stdin.readlines()[0]\n(m, n) = [int(x) for x in numbers.split(' ')]\nif m % 2 == 0 or n % 2 == 0:\n\tprint(int(m * n / 2))\nelse:\n\tprint(int((m * n - 1) / 2))\n","w = input()\nw = w.split()\nw = list(w)\nfor (i, elem) in enumerate(w):\n\tw[i] = int(elem)\nm = w[0]\nn = w[1]\ns = m * n\nif s % 2 == 0:\n\tprint(int(s / 2))\nelse:\n\tprint(int((s - 1) / 2))\n","(n, m) = map(int, input().split())\ns_rec = n * m\ns_dom = 2 * 1\nanswer = s_rec // s_dom\nprint(answer)\n","import math\n\ndef main():\n\t(m, n) = list(map(int, input().split()))\n\tprint(int(math.floor(n * m * 0.5)))\nmain()\n","(a, b) = input().split()\nm = int(a)\nn = int(b)\nif m % 2 == 0:\n\tprint(str(m // 2 * n))\nelse:\n\tprint(str(m // 2 * n + n // 2))\n","from sys import stdin, stdout\n\ndef read_int_input():\n\treturn map(int, stdin.readline().rstrip().split())\n\ndef read_str_input():\n\treturn stdin.readline().rstrip().split()\n\ndef write_output(result):\n\treturn stdout.write(str(result) + '\\n')\n\ndef main():\n\t(m, n) = read_int_input()\n\twrite_output(m * n // 2)\nmain()\n","list = input().split()\n(M, N) = map(int, list)\nif M % 2 != 0 and N % 2 != 0:\n\ta = (M - 1) / 2\n\tb = N\n\tc = (N - 1) / 2\n\td = a * b + c\n\td = int(d)\n\tprint(d)\nelse:\n\te = M * N / 2\n\te = int(e)\n\tprint(e)\n","n = input()\nM = int(str(n).split()[0])\nN = int(str(n).split()[1])\narea = M * N\nif area % 2 == 0:\n\tprint(int(area / 2))\nelse:\n\tprint(int((area - 1) / 2))\n","from math import floor\n(m, n) = map(int, input().split(' '))\nboard_area = m * n\ndomino_area = 2 * 1\nans = floor(board_area / domino_area)\nprint(ans)\n","nums = input().split(' ')\nm = int(nums[0])\nn = int(nums[1])\ntotal = m * n\nfit = int(total / 2)\nprint(fit)\n","s = input().split(' ')\nmul = int(s[0]) * int(s[1])\nprint(mul // 2)\n","(m, n) = map(int, input().split())\nsq = m * n\nrem = sq % 2\nans = sq - rem\nprint(ans // 2)\n","(m, n) = map(int, input().split())\nfrom math import *\na = max(m, n)\nb = min(m, n)\np = a // 2 * b\nif a % 2 != 0:\n\tp = p + b // 2\n\tprint(p)\nelse:\n\tprint(p)\n","(m, n) = map(int, input().split())\nt = m // 2 * n\nif m % 2 == 1:\n\tt += n // 2\nprint(t)\n","(m, n) = map(int, input().split())\nsur = m * n\ntiles = sur // 2\nprint(tiles)\n","def test07():\n\t(m, n) = map(int, input().strip().split(' ')[0:2])\n\tif m * n % 2 == 0:\n\t\tprint(int(m * n / 2))\n\telse:\n\t\tprint(int((m * n - 1) / 2))\ntest07()\n","def ans(a, b):\n\treturn a * b // 2\n(n, k) = map(int, input().split(' '))\nprint(ans(n, k))\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nif m % 2 == 1:\n\ty = int(m / 2) * n + int(n / 2)\n\tprint(int(y))\nelse:\n\ty = int(m * n / 2)\n\tprint(y)\n","(a, b) = list(map(int, input().split()))\nif a % 2 == 0:\n\tprint(a // 2 * b)\nelif a % 2 != 0:\n\tt = a // 2 * b + b // 2\n\tprint(t)\n","key_input = input().split(' ')\nprint(int(int(key_input[0]) * int(key_input[1]) / 2))\n","list1 = input().split()\nm = int(list1[0])\nn = int(list1[1])\ndiv = n * m // 2\nprint(div)\n","(m, n) = map(int, input().split())\nM = m // 2\na = m % 2\nx = n * M\nif a == 1:\n\tN = n // 2\n\tb = n % 2\n\tx = x + N\nprint(x)\n","(m, n) = map(int, input().split())\npd = m // 2\nans = pd * n\nif m % 2 == 1:\n\tsd = n // 2\n\tans += sd\nprint(ans)\n","inputList = input().split()\nvalues = [int(x) for x in inputList]\nnumber = 0\nif values[0] % 2 == 0 or values[1] % 2 == 0:\n\tif values[0] % 2 == 0 and values[1] % 2 == 0:\n\t\tnumber = values[0] / 2 * values[1]\n\telif values[0] % 2 == 0 and values[1] % 2 == 1:\n\t\tnumber = values[0] / 2 * values[1]\n\telif values[1] % 2 == 0 and values[0] % 2 == 1:\n\t\tnumber = values[1] / 2 * values[0]\nelse:\n\tnumber = (values[0] - 1) / 2 * values[1] + (values[1] - 1) / 2\nprint(int(number))\n","def do(m, n):\n\tif m > n:\n\t\t(m, n) = (n, m)\n\tans = 0\n\tif m % 2 == 0:\n\t\tans = m // 2 * n\n\telse:\n\t\tans = m // 2 * n + n // 2\n\tprint(ans)\n(m, n) = map(int, input().split())\ndo(m, n)\n","q = input().split()\nM = int(q[0])\nN = int(q[1])\nif M % 2 == 0 and N % 2 == 0:\n\tt = M * N // 2\nelif M % 2 == 0:\n\tt = M * (N - 1) // 2 + M // 2\nelif N % 2 == 0:\n\tt = N * (M - 1) // 2 + N // 2\nelse:\n\tt = (M - 1) * (N - 1) // 2 + M // 2 + N // 2\nprint(t)\n","(panjang, lebar) = input().split()\nprint(int(panjang) * int(lebar) // 2)\n","(m, n) = [int(x) for x in input().split()]\ndomino_size = 2 * 1\nboard = m * n\nsize = board // domino_size\nprint(size)\n","import math\n\ndef main():\n\t(n, m) = [int(s) for s in input().split(' ')]\n\tl1 = n / 2\n\tw1 = m\n\tl2 = n\n\tw2 = m / 2\n\tprint(math.floor(max(l1 * w1, l2 * w2)))\nmain()\n","import math\n(n, m) = input().split(' ')\nn = int(n)\nm = int(m)\nresult = n * m // 2\nprint(result)\n","try:\n\t(m, n) = [int(i) for i in input().split(' ')]\n\tif m >= 1 and m >= 1 and (n >= m) and (m <= 16) and (n <= 16):\n\t\tprint(int(m * n // 2))\nexcept:\n\tpass\n","Dimensions = input().split()\nfor measure in Dimensions:\n\ti = Dimensions.index(measure)\n\tDimensions[i] = float(measure)\nprint(int(Dimensions[0] * Dimensions[1] / 2.0))\n","(M, N) = [int(i) for i in input().split(' ')]\nresult = M * N / 2\nprint(int(result))\n","import sys\nimport math\n(M, N) = map(int, sys.stdin.readline().split())\nprint(math.floor(M * N / 2))\n","(a, c) = map(int, input().split(' '))\ncount = 0\ni = 0\nl = max(a, c)\nb = min(a, c)\ni = 1\nwhile b > 0:\n\tif b >= 2:\n\t\tcount = l\n\t\tcount = count * i\n\t\tb -= 2\n\t\ti += 1\n\telse:\n\t\tm = l // 2\n\t\tcount = count + m\n\t\tb -= 1\nprint(count)\n","l = input()\n(n, m) = l.split()\nn = int(n)\nm = int(m)\nprint(n * m // 2)\n","l = list(map(int, input().split()))\n(m, n) = (l[0], l[1])\nimport math\nx = max(n, m)\ny = min(n, m)\nprint(int(math.floor(x * y / 2)))\n","import math\n(M, N) = input().split()\nM = int(M)\nN = int(N)\na = M * N\nres = math.trunc(a / 2)\nprint(res)\n","a = input().split()\n\ndef f(l):\n\tb = [int(i) for i in l]\n\treturn b[0] * b[-1] // 2\nprint(f(a))\n","def domin(input_user):\n\tn = input_user[0]\n\tm = input_user[1]\n\treturn int(m * n / 2)\ninput_user = list(map(int, input().split()))\nprint(domin(input_user))\n","(x, y) = map(int, input('').split())\nresult = x * y\nfinal = int(result / 2)\nprint(final)\n","(first, second) = input().split(' ')\nm = int(first)\nn = int(second)\nprint(int(m * n / 2))\n","l = input().split()\na = int(l[0])\nb = int(l[1])\nc = a * b\nif c % 2 == 0:\n\tk = c // 2\nelse:\n\tk = int(c / 2)\nprint(k)\n","def domino(rec):\n\ttot = rec // 2\n\treturn tot\n(n, m) = map(int, input().strip().split(' '))\nr = n * m\nprint(domino(r))\n","x = input()\ny = x.split(' ')\njavab = 0\nif int(y[0]) % 2 == 0:\n\tjavab = int(y[0]) // 2 * int(y[1])\nelif int(y[1]) % 2 == 0:\n\tjavab = int(y[1]) // 2 * int(y[0])\nelse:\n\tjavab = int(y[0]) // 2 * int(y[1]) + int(y[1]) // 2\nprint(javab)\n","n = input()\nl = n.split()\nm = int(l[0])\nn = int(l[1])\nif 1 <= m <= 16 and 1 <= n <= 16:\n\ti = n * m / 2\n\tprint(int(i))\n","board = input().split()\nM = int(board[0])\nN = int(board[1])\nnum = M * N\nprint(num // 2)\n","from math import *\n(M, N) = input().split()\nM = int(M)\nN = int(N)\nmulti = M * N\ndivided_by = 2 * 1\nif multi / divided_by == 0:\n\tprint(multi / divided_by)\nelse:\n\tprint(floor(multi / divided_by))\n","(x, y) = map(int, input().split())\na = int(x / 2)\nb = int(y / 1)\nprint(int(y * x / 2))\n","data = [int(x) for x in input().split()]\nprint(int(data[0] * data[1] / 2))\n","l = [int(i) for i in input().split()]\nl.sort()\nlonger = l[1]\nshorter = l[0]\ns = 0\nadditional = 0\nrest = 0\nif longer > 2:\n\tif shorter < 2:\n\t\ts = shorter * int(longer / 2)\n\telse:\n\t\ts = int(shorter / 2) * longer\n\t\trest = shorter - 2 * int(shorter / 2)\n\t\tadditional = int(longer / 2) * rest\n\t\ts = s + additional\nelif longer == 2:\n\ts = shorter\nelse:\n\ts = 0\nprint(s)\n","inp = input()\n(m, n) = [int(x) for x in inp.split()]\nprint(m * n // 2)\n","import math\nx = input()\nxx = x.split()\nm = int(xx[0])\nn = int(xx[1])\nif n % 2 == 0:\n\tprint(int(n / 2 * m))\nelse:\n\tprint(int(math.floor(n / 2) * m + math.floor(m / 2)))\n","razmery = input()\nmassiv = razmery.split()\nm = int(massiv[0])\nn = int(massiv[1])\ni = 2 * 1\ns = m * n\ndomino = s // i\nprint(domino)\n","(length, width) = map(int, input().split())\nnum = 0\nif length >= 2:\n\tnum = length // 2 * width\nif length % 2 == 1:\n\tnum = num + width // 2\nprint(num)\n","(n, m) = list(map(lambda num: int(num), input().split(' ')))\nprint(n * m // 2)\n","(M, N) = map(int, input().split())\nif 0 <= M <= N <= 16:\n\tif M % 2 == 0:\n\t\tp = M / 2 * N\n\telif N % 2 == 0:\n\t\tp = N / 2 * M\n\telse:\n\t\tp = (N - 1) / 2 * M + (M - 1) / 2\nprint(int(p))\n","import sys\nimport math\n\ndef main():\n\tuser_input = input()\n\tuser_input = user_input.split()\n\tsize = int(user_input[0]) * int(user_input[1])\n\tprint(math.floor(size / 2))\nmain()\n","s = input()\n(nnn, mmm) = s.split()\nn = int(nnn)\nm = int(mmm)\nsize = n * m\nprint(size // 2)\n","(n, m) = tuple(map(int, input().split()))\nz = int(n * m / 2)\nprint(z)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\np = m * n\nif p % 2 == 0:\n\tr = p / 2\nelse:\n\tr = (p - 1) / 2\nr = int(r)\nprint(r)\n","(M, N) = list(map(int, input().split()))\nSub = M * N\nDominoes = Sub // 2\nprint(Dominoes)\n","def domino(a, b):\n\tarea_domino = 2 * 1\n\tarea_board = a * b\n\treturn int(area_board / area_domino)\n(a, b) = map(int, input().split())\nprint(domino(a, b))\n","import math\n(n, k) = input().split()\nn = int(n)\nk = int(k)\nx = math.floor(n * k / 2)\nprint(x)\n","(n, k) = map(int, input().split())\nans = 0\nwhile ans <= n * k:\n\tans += 2\nans -= 2\nprint(int(ans / 2))\n","dim = input()\npos = dim.find(' ')\nA = dim[0:pos]\nB = dim[pos:]\nC = int(A)\nD = int(B)\nmul = C * D\ndiv = mul / 2\nprint(int(div))\n","(x, y) = input().split()\nm = int(x) * int(y) * 0.5\nprint(int(m))\n","(a, b) = map(int, input().split())\ns = a // 2 * b\nif a % 2 != 0:\n\ts += b // 2\nprint(s)\n","(m, n) = [int(x) for x in input().split()]\nresult = 0\nwhile n > 1:\n\tresult += m\n\tn -= 2\nif n == 1:\n\tresult += m // 2\nprint(result)\n","(chieuDai, chieuRong) = map(int, input().split())\nsoDominoToiDa = int(chieuDai * chieuRong / 2)\nprint(soDominoToiDa)\n","import math\nMN = input()\nMN = MN.split(' ')\nM = int(MN[0])\nN = int(MN[1])\nif M % 2 == 0 and N % 2 == 0:\n\tprint(int(N * M / 2))\nelse:\n\tprint(math.trunc(N * M / 2))\n","A = [int(x) for x in input().split()]\nif A[0] * A[1] % 2 == 0:\n\ti = A[0] * A[1] / 2\n\tprint(str(int(i)))\nelse:\n\tprint(str(int((A[0] * A[1] - 1) / 2)))\n","m_n = input()\n(m, n) = m_n.split()\n(m, n) = (int(m), int(n))\nprint(m * n // 2)\n","(M, N) = input().split()\nm = int(M)\nn = int(N)\nA = m * n\nif A % 2 == 0:\n\tprint(int(A / 2))\nelse:\n\tA - 1\n\tprint(int(A / 2))\n","def f(x, y):\n\treturn int(x * int(y / 2) + y % 2 * int(x / 2))\n\ndef main():\n\tl = input().split(' ')\n\tx = int(l[0])\n\ty = int(l[1])\n\tout = f(max(x, y), min(x, y))\n\tprint(out)\nmain()\n","a = input().split()\ny = [int(x) for x in a]\nprod = 1\nfor x in y:\n\tprod *= x\nout = int(prod / 2)\nprint(out)\n","(m_str, k_str) = input().split(' ')\nm = int(m_str)\nk = int(k_str)\nif m * k % 2 == 0:\n\tprint(int(m * k / 2))\nelse:\n\tprint(int((m * k - 1) / 2))\n","from math import floor\nq = list(input().split(' '))\nm = q[0]\nn = q[1]\nres = int(m) * int(n)\nres = floor(res / 2)\nprint(res)\n","import sys\ninf = float('inf')\nabc = 'abcdefghijklmnopqrstuvwxyz'\nabd = {'a': 0, 'b': 1, 'c': 2, 'd': 3, 'e': 4, 'f': 5, 'g': 6, 'h': 7, 'i': 8, 'j': 9, 'k': 10, 'l': 11, 'm': 12, 'n': 13, 'o': 14, 'p': 15, 'q': 16, 'r': 17, 's': 18, 't': 19, 'u': 20, 'v': 21, 'w': 22, 'x': 23, 'y': 24, 'z': 25}\n(mod, MOD) = (1000000007, 998244353)\nvow = ['a', 'e', 'i', 'o', 'u']\n(dx, dy) = ([-1, 1, 0, 0], [0, 0, 1, -1])\n\ndef get_array():\n\treturn list(map(int, sys.stdin.readline().strip().split()))\n\ndef get_ints():\n\treturn map(int, sys.stdin.readline().strip().split())\n\ndef input():\n\treturn sys.stdin.readline().strip()\n(m, n) = get_ints()\nmaxi = max(m, n)\nmini = min(m, n)\nans = m // 2 * n\nif m & 1:\n\tans += n // 2\nprint(ans)\n","(m, n) = map(int, input().split())\nr = m // 2 * n\nif m % 2 != 0:\n\tr += n // 2\nprint(r)\n","input1 = [int(v) for v in input().split(' ')]\ny = input1[0]\nz = input1[1]\nx = z * y\nif x % 2 == 0:\n\tprint(x // 2)\nelif x == 1:\n\tprint(0)\nelse:\n\tfor i in range(x):\n\t\tif (x - i) % 2 == 0:\n\t\t\tprint((x - i) // 2)\n\t\t\tbreak\n\t\telse:\n\t\t\tcontinue\n","(a, b) = map(int, input().split())\nc = a * b\ne = c / 2\nprint(int(e))\n","import math\nsize = input().split()\nprint(math.floor(int(size[0]) * int(size[1]) / 2))\n","(m, n) = map(int, input().split())\nif m % 2 == 0 or n % 2 == 0:\n\ti = m * n // 2\n\tprint(i)\nelif m % 2 != 0 and n % 2 != 0:\n\tj = m * n // 2\n\tprint(j)\nelif m % 2 == 0 and n % 2 == 0:\n\tk = m * n // 2\n\tprint(k)\n","(m, n) = map(int, input().split())\nif m > 1:\n\tWidth = n\n\tHeight = m // 2\n\tExtra = 0\n\tif m % 2 != 0:\n\t\tExtra = n // 2\n\tNumberOfDominoes = Width * Height + Extra\nelse:\n\tNumberOfDominoes = n // 2\nprint(NumberOfDominoes)\n","(n, m) = map(int, input().split())\ns = 2 * 1\nc = 0\nwhile n * m >= s:\n\ts += 2\n\tc += 1\nprint(c)\n","s = input()\ns = s.split(' ')\n(x, y) = (int(s[0]), int(s[1]))\nprint(x * y >> 1)\n","(M, N) = map(int, input().split(' '))\nmulit = M * N\nde = mulit // 2\nprint(de)\n","(n, k) = map(int, input().strip().split(' '))\narea = n * k\nprint(area // 2)\n","(n, k) = map(int, input().split(' '))\nd = 2 * 1\nf = n * k // d\nprint(f)\n","astr = input().split()\n(m, n) = (int(astr[0]), int(astr[1]))\nproduct = m * n\nprint(product // 2)\n","(m, n) = map(int, input().split())\nprint(max(m // 2 * n // 1, m // 1 * n // 2))\n","a = input()\n(m, n) = a.split(' ')\nm = int(m)\nn = int(n)\nif m >= 1 and n >= m:\n\tif n <= 16:\n\t\tres = m * n // 2\n\t\tprint(res)\n","import sys\ndata = list(map(int, sys.stdin.read().split()))\nprint(data[0] * data[1] // 2)\n","inputDimension = input().split(' ')\ntotalDimension = int(inputDimension[0]) * int(inputDimension[1])\nprint(int(totalDimension / 2))\n","list = [int(i) for i in input().split()]\nn = list[0] * list[1] // 2\nprint(n)\n","from math import *\n(x, y) = input().split()\nx = int(x)\ny = int(y)\nz = x * y // 2\nprint(z)\n","while True:\n\t(m, n) = map(int, input().split(' '))\n\tif 1 > m > n > 16:\n\t\tprint('please provide a number between 1 and 16')\n\t\tbreak\n\tbreak\narea_of_rectangle = m * n\narea_of_domino = 2\nif area_of_rectangle >= area_of_domino:\n\tprint(int(area_of_rectangle / area_of_domino))\nelse:\n\tprint(0)\n","from sys import stdin\n\ndef readInts():\n\treturn map(int, stdin.readline().strip().split())\n\ndef solve(m, n):\n\tout = m * n // 2\n\treturn out\n\ndef run():\n\t(m, n) = readInts()\n\tprint(solve(m, n))\nrun()\n","a = [int(x) for x in input().split(' ')]\nfor num in a:\n\tif num % 2 != 0:\n\t\tnum -= 1\nprint(int(a[0] * a[1] / 2))\n","(M, N) = map(int, input().split())\nl = M * N\nm = l // 2\nprint(m)\n","(m, n) = [int(e) for e in input().split()]\nprint(m * n // 2)\n","import re\nboard = input()\nsetq = re.compile('\\\\d{2}|\\\\d')\nnums = setq.findall(board)\nm = int(nums[0])\nn = int(nums[1])\nif m == 1 and n % 2 == 0:\n\tprint(int(n / 2))\nelif m == 1 and n % 2 == 1:\n\tprint(int((n - 1) / 2))\nelif m % 2 and n % 2 == 1:\n\tprint(int((m - 1) / 2 * n + (n - 1) / 2))\nelif m % 2 == 0 and n % 2 == 0:\n\tprint(int(m / 2 * n))\nelif m % 2 == 0 and n % 2 == 1:\n\tprint(int(m / 2 * n))\nelif m % 2 == 1 and n % 2 == 0:\n\tprint(int((m - 1) / 2 * n + n / 2))\n","inp_data = input()\nparsed_data = list(inp_data.split(' '))\ns_field = int(parsed_data[0]) * int(parsed_data[1])\nprint(s_field // 2)\n","def parser():\n\twhile 1:\n\t\tdata = list(input().split(' '))\n\t\tfor number in data:\n\t\t\tif len(number) > 0:\n\t\t\t\tyield number\ninput_parser = parser()\n\ndef get_word():\n\tglobal input_parser\n\treturn next(input_parser)\n\ndef get_number():\n\tdata = get_word()\n\ttry:\n\t\treturn int(data)\n\texcept ValueError:\n\t\treturn float(data)\nimport math\nM = get_number()\nN = get_number()\nif M % 2 == 1 and N % 2 == 1:\n\tanswer = (M * N - 1) / 2\nelse:\n\tanswer = M * N / 2\nprint(int(answer))\n","x = input().split()\nm = int(x[0])\nn = int(x[1])\nif m % 2 == 0:\n\ta = m / 2\n\tprint(int(a * n))\nif m % 2 != 0 and n % 2 == 0:\n\ta = int(m / 2)\n\tprint(int(a * n + n / 2))\nif m % 2 != 0 and n % 2 != 0:\n\ta = int(m / 2)\n\tb = int(n / 2)\n\tprint(int(a * n + b))\n","(l, w) = map(int, input().split(' '))\narea = l * w\nprint(int(area / 2))\n","inp = [int(i) for i in input('').split(' ')]\nres = inp[0] * inp[1] // 2\nprint(res)\n","import math\nline = input()\nargs = line.split(' ')\nm = int(args[0])\nn = int(args[1])\ns = m * n\nt = math.floor(s / 2)\nprint(t)\n","values = input().split()\nside1 = int(values[0])\nside2 = int(values[1])\ndomino = 2\nsum_of_sides = side1 * side2\nitogo = sum_of_sides // domino\nprint(itogo)\n","(n, m) = map(int, input().split())\ns = n * m\nr = s // 2\nprint(r)\n","l = list(map(int, input().split()))\narea = l[0] * l[1]\nprint(area // 2)\n","sides = [int(el) for el in input().split(' ')]\nprint(sides[0] * sides[1] // 2)\n","(m, n) = map(int, input().split())\nrec = m * n\ndom = 2\nprint(rec // dom)\n","X = input().split()\nM = int(X[0])\nN = int(X[1])\nprint(M * N // 2)\n","input_arr = [int(i) for i in input().split()]\nm = input_arr[0]\nn = input_arr[1]\nm1 = m % 2\nn1 = n % 2\nm2 = m // 2\nn2 = n // 2\nans = m2 * n2 * 2 + (0 if m1 == 0 else n2) + (0 if n1 == 0 else m2)\nprint(ans)\n","import math\ndata = input()\n(M, N) = [int(x) for x in data.split()]\nboardSquares = M * N\nprint(math.floor(M * N / 2))\n","def solve(m, n):\n\tta = 2 * 1\n\tba = m * n\n\treturn ba // ta\n(m, n) = map(int, input().split(' '))\nprint(solve(m, n))\n","nums = input().split()\n(m, n) = (int(nums[0]), int(nums[1]))\nif m % 2 == 0:\n\tnum = int(m / 2) * n\nelse:\n\tnum = int(m / 2) * n + int(n / 2)\nprint(num)\n","array = input()\narray = array.split()\narray = [int(i) for i in array]\noutput = int(array[0] * array[1] // 2)\nprint(output)\n","import os\nimport sys\n(n, m) = map(int, input().split(' '))\nif m > n:\n\t(n, m) = (m, n)\nans = int(n / 2) * m\nif n % 2 == 1:\n\tans += int(m / 2)\nprint(ans)\n","numeros = input()\nnumeros = numeros.split()\nM = int(numeros[0])\nN = int(numeros[1])\nTotal = 0\nif 1 <= M and M <= N and (N <= 16):\n\tTotal = M // 2 * N\nif M % 2 == 0:\n\tTotal = Total\nelse:\n\tTotal = Total + N // 2\nprint(Total)\n","s = input()\nline = s.split()\nline = [int(e) for e in line]\narea = line[0] * line[1]\nprint(area // 2)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\ndomin = m * n // 2\nprint(domin)\n","(a, b) = (int(x) for x in input().split(' '))\nc = int(a)\nd = int(b)\nn = c // 2\nsum = n * b\nif c % 2 == 1:\n\tsum += d // 2\nprint(sum)\n","line = input()\n(m, n) = line.split()\n(m, n) = (int(m), int(n))\nresult = n * m // 2\nprint(result)\n","def go():\n\t(n, m) = [int(i) for i in input().split(' ')]\n\ttotal = 0\n\tif n % 2 == 0:\n\t\ttotal += n // 2 * m\n\telif m % 2 == 0:\n\t\ttotal += m // 2 * n\n\telse:\n\t\ttotal += n // 2 * m + m // 2\n\treturn total\nprint(go())\n","(m, n) = map(int, input().split())\nif m == 0 and n == 0:\n\tprint(0)\ns = m * n\ndominos = s // 2\nprint(dominos)\n","zeile1 = input('')\nwertezeile1 = []\nzahl = ''\nfor i in range(len(zeile1)):\n\tif zeile1[i] != ' ':\n\t\tzahl = zahl + zeile1[i]\n\telse:\n\t\twertezeile1.append(int(zahl))\n\t\tzahl = ''\n\tif i == len(zeile1) - 1:\n\t\twertezeile1.append(int(zahl))\n\t\tzahl = ''\ngroesex = wertezeile1[0]\ngroesey = wertezeile1[1]\nif groesex * groesey % 2 == 0:\n\tergebnis = groesex * groesey / 2\nelse:\n\tergebnis = (groesex * groesey - 1) / 2\nprint(int(ergebnis))\n","from sys import stdin, stdout, setrecursionlimit\nimport math\n\ndef get_int():\n\treturn int(stdin.readline().strip())\n\ndef get_ints():\n\treturn map(int, stdin.readline().strip().split())\n\ndef get_string():\n\treturn stdin.readline().strip()\n\ndef get_list():\n\treturn list(map(int, stdin.readline().strip().split()))\n(m, n) = get_ints()\nstdout.write(str(math.floor(n * m / 2)))\n","(M, N) = map(int, input().split(' '))\nq = M * N // 2\nprint(q)\n","import math\nlst = list(map(int, input().rstrip().split()))\nm = int(lst[0])\nn = int(lst[1])\nx1 = m * n\nx2 = int(x1 / 2)\nprint(x2)\n","from sys import stdin, stdout\n\ndef main():\n\tip = stdin.readline().split()\n\tm = int(ip[0])\n\tn = int(ip[1])\n\tstdout.write(str(m * n // 2))\nmain()\n","import math\n(m, n) = map(int, input().split(' '))\na = 2\nb = 1\ns1 = a * b\ns2 = m * n\ni = s2 / s1\nprint(int(math.floor(i)))\n","(m, n) = map(int, input().split())\ntotal_area = m * n\ndominoes = int(total_area / 2)\nprint(dominoes)\n","def domino(a, b):\n\tsum = 0\n\tsum += a * (b // 2)\n\tif b % 2 == 1:\n\t\tsum += a // 2\n\treturn sum\n(a, b) = map(int, input().split())\nprint(domino(a, b))\n","from sys import stdin\n(m, n) = map(int, stdin.read().split())\nprint(m * n // 2)\n","dist = input()\ndist = dist.split()\nN = int(dist[0])\nM = int(dist[1])\nA = N * M\nr = A // 2\nprint(r)\n","import sys\nif sys.version_info.major < 3:\n\tinput = raw_input\n\ndef main():\n\t(m, n) = map(int, input().split())\n\treturn m * n // 2\nprint(main())\n","nums = input()\n(n, m) = nums.split()\nmult = int(n) * int(m)\nif mult % 2 == 0:\n\tres = mult / 2\nelse:\n\tres = (mult - 1) / 2\nprint(int(res))\n","def domino(a, b):\n\tif a * b < 2:\n\t\treturn 0\n\telif a == 1:\n\t\treturn int(b / 2)\n\telif b == 1:\n\t\treturn int(a / 2)\n\telse:\n\t\tresult = a * int(b / 2)\n\t\tif b % 2 != 0:\n\t\t\tresult += int(a / 2)\n\t\treturn result\nx = input()\n(a, b) = x.split()\n(a, b) = (int(a), int(b))\nprint(domino(a, b))\n","(m, n) = [int(x) for x in input().split()]\narea_of_board = m * n\narea_of_domino = 2\nno_of_domino = int(area_of_board / 2)\nverify = type(no_of_domino)\nif verify == float:\n\tprint(round(no_of_domino) - 1)\nelif verify == int:\n\tprint(round(no_of_domino))\n","(m, n) = [int(i) for i in input().split()]\narea = m * n\nif area % 2 == 1:\n\tarea = area - 1\nprint(area // 2)\n","(m, n) = map(int, input().split())\nx = 2\ny = m * n\nz = y // x\nprint(z)\n","(m, n) = map(int, input().split())\nx = m * n\nif x < 2:\n\tprint('0')\nelif x == 2:\n\tprint('1')\nelse:\n\ta = m // 2\n\tb = m % 2\n\tc = n // 2\n\tif b == 0:\n\t\tprint(n * a)\n\telse:\n\t\tprint(n * a + c)\n","(m, n) = map(int, input().split(' '))\nda = 2\nba = m * n\nprint(int(ba / da))\n","import sys\nnumbers = sys.stdin.readline()\nm = int(numbers.split(' ')[0])\nn = int(numbers.split(' ')[1])\nspaces = n * m\nmn = int(spaces / 2)\nprint(mn)\n","(a, b) = map(int, input().split())\nprint('{0}'.format(a * b // 2))\n","(l, b) = map(int, input().split())\narea = l * b\nprint(area // 2)\n","def main():\n\t(m, n) = ints_from_input()\n\tresult = 0\n\tif m / 2 > 0:\n\t\tresult += m // 2 * n\n\tif m % 2:\n\t\tresult += n // 2\n\treturn result\n\ndef ints_from_input():\n\treturn [int(i) for i in input().split()]\nprint(main())\n","tablero = input()\ntablero2 = [int(i) for i in tablero.split(' ')]\narea = tablero2[0] * tablero2[1]\nresultado = area // 2\nprint(resultado)\n","try:\n\t(m, n) = map(int, input().split())\n\tprint(m * n // 2)\n\tpass\nexcept Exception:\n\tpass\n","try:\n\tprint(eval('*'.join(input().split())) // 2)\nexcept:\n\tpass\n","board = [int(a) for a in input().split(' ')]\nprint(board[0] * board[1] // 2)\n","(M, N) = map(int, input().split())\nndominos = M // 2 * N\nif M % 2 == 1:\n\tndominos += N // 2\nprint(ndominos)\n","(m, n) = map(int, input().split(' '))\nsum = 0\nsum += n * m // 2\nprint(sum)\n","import string\narr = list(map(int, input().split()))\nn = arr[0]\nm = arr[1]\nnumberOfSquares = n * m\nnumberOfDominos = numberOfSquares // 2\nprint(numberOfDominos)\n","x = str(input())\nn = str(x[-2:])\nm = str(x[:2])\nn = int(n)\nm = int(m)\nw = n * m\nj = int(w / 2)\nprint(j)\n","raw_str = input().split()\nM = int(raw_str[0])\nN = int(raw_str[1])\nmatrix = [[0 for x in range(N)] for y in range(M)]\ncount = 0\nfor i in range(0, M):\n\tfor j in range(0, N):\n\t\tif matrix[i][j] == 0:\n\t\t\tif i + 1 != M and matrix[i + 1][j] == 0:\n\t\t\t\tmatrix[i][j] = 1\n\t\t\t\tmatrix[i + 1][j] = 1\n\t\t\t\tcount += 1\n\t\t\t\tcontinue\n\t\t\tif i - 1 != -1 and matrix[i - 1][j] == 0:\n\t\t\t\tmatrix[i][j] = 1\n\t\t\t\tmatrix[i - 1][j] = 1\n\t\t\t\tcount += 1\n\t\t\t\tcontinue\n\t\t\tif j + 1 != N and matrix[i][j + 1] == 0:\n\t\t\t\tmatrix[i][j] = 1\n\t\t\t\tmatrix[i][j + 1] = 1\n\t\t\t\tcount += 1\n\t\t\t\tcontinue\n\t\t\tif j - 1 != -1 and matrix[i][j - 1] == 0:\n\t\t\t\tmatrix[i][j] = 1\n\t\t\t\tmatrix[i][j - 1] = 1\n\t\t\t\tcount += 1\n\t\t\t\tcontinue\nprint(count)\n","(n, m) = input().split()\nn = int(n)\nm = int(m)\nres = 0\nflag = 0\nif m % 2 == 0:\n\tres = int(m / 2)\n\tres = res * n\nelse:\n\tres = int(m / 2)\n\tres = res * n\n\tres += int(n / 2)\nprint(res)\n","(m, n) = map(int, input().split())\npoN = 0\npoM = 0\nif n % 2 != 0:\n\tprint(m // 2 + n // 2 * m)\nelse:\n\tprint(n // 2 * m)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nt = 2\nb = m * n\nprint(b // t)\n","import math\n(m, n) = map(int, input().split())\nmul = m * n\ndiv = mul / 2\nres = math.floor(div)\nprint(res)\n","MN = input().split(' ')\ncol = int(MN[0])\nrow = int(MN[1])\ntbo = [1, 1]\nboard = []\nfor _ in range(row):\n\tc = []\n\tfor _ in range(col):\n\t\tc.append(0)\n\tboard.append(c)\nif row % 2 == 0:\n\tx = row / 2\n\tpiles = x * col\nelif col % 2 == 0:\n\tx = col / 2\n\tpiles = x * row\nelif col % 2 != 0 and row % 2 != 0:\n\ty1 = col - 1\n\tx1 = y1 / 2 * row\n\ty2 = row - 1\n\tx2 = y2 / 2\n\tpiles = x1 + x2\nprint(round(piles))\n","l = input().split()\nif int(l[0]) == 1 and int(l[1]) == 1:\n\tprint('0')\nelif int(l[0]) % 2 == 0 or int(l[1]) % 2 == 0:\n\tprint(str(int(int(l[0]) * int(l[1]) / 2)))\nelse:\n\tprint(str(int((int(l[0]) * int(l[1]) - 1) / 2)))\n","i = list(map(int, input().split()))\nm = i[0]\nn = i[1]\nx = m * n\nprint(x // 2)\n","line = input()\ntemp = line.split()\nm = int(temp[0])\nn = int(temp[1])\nif m == 1:\n\tprint(int(n // 2))\nif m == 2:\n\tprint(n)\nans = 0\nif m > 2:\n\tans += m // 2 * n\n\tif m % 2 == 1:\n\t\tans += n // 2\n\tprint(ans)\n","from math import floor\n(m, n) = input('').split(' ')\n(m, n) = (int(m), int(n))\narea = m * n\nnDominoes = floor(area / 2)\nprint(nDominoes)\n","(m, n) = map(int, input().split())\nar = m * n\nnm = ar // 2\nprint(nm)\n","MN = input().split(' ')\nm = int(MN[0])\nn = int(MN[1])\nproduct = m * n\nblocks = product // 2\nprint(blocks)\n","(m, n) = [int(x) for x in input().split()]\ni = 0\nj = 0\nwhile m > 1:\n\ti = i + n\n\tm = m - 2\n\tif m <= 1:\n\t\tbreak\nwhile n >= 2 and m >= 1:\n\tj += 1\n\tn = n - 2\n\tif n < 2:\n\t\tbreak\nk = i + j * m\nprint(k)\n","k = 1\nn = input()\nn = n.split()\nfor i in n:\n\tk = int(i) * int(k)\nprint(k // 2)\n","from math import *\n(m, n) = input().split()\nareamn = int(m) * int(n)\nans = floor(areamn / 2)\nprint(ans)\n","dat = input()\nlqw = dat.split(' ')\nlol = []\nfor i in lqw:\n\tlol.append(int(i))\nprint(lol[0] * lol[1] // 2)\n","arr = input().split()\nm = int(arr[0])\nn = int(arr[1])\nprint(m * n // 2)\n","T = str(input()).split(' ')\nM = int(T[0])\nN = int(T[1])\nnumberofdomino = 0\nif M >= 1 and M <= N:\n\tif N >= M and N <= 16:\n\t\tareaofboard = M * N\n\t\tnumberofdomino = areaofboard / 2\n\t\tnumberofdomino = int(str(numberofdomino).split('.')[0])\nprint(numberofdomino)\n","(n, m) = list(map(int, input().split()))\nc = n * m\nprint(c // 2)\n","a = input()\nlist_1 = a.split()\nm = int(list_1[0])\nn = int(list_1[1])\no = int(m * n / 2)\nprint(o)\n","import sys\nimport math\nfrom operator import mul\n(a, b) = map(int, sys.stdin.readline().split())\nprint(math.floor(int(a) * int(b) / 2))\n","import math\n(M, N) = map(int, input().split())\nprint(str(math.floor(M * N / 2)))\n","(x, y) = map(int, input().split())\nd = 0\n\ndef domino(x, y):\n\treturn int(x / 2) * y\nif x % 2 == 0:\n\td = domino(x, y)\nelse:\n\td = domino(x, y)\n\td += domino(y, 1)\nprint(d)\n","(M, N) = input().split()\nM = int(M)\nN = int(N)\na = M * N\nx = M // 2\ny = N // 2\ns = x * y\na1 = s * 2\na2 = a - a1\nr = a2 // 2\nf = s + r\nprint(f)\n","l = input().split(' ')\nrows = int(l[0])\ncols = int(l[1])\nres = rows // 2 * cols\nif rows % 2 != 0:\n\tres += cols // 2\nprint(res)\n","(a, b) = map(int, input().split())\nz = 0\nz = a * b // 2\nprint(z)\n","numbers = input()\n(M, N) = numbers.split(' ')\nm = eval(M)\nn = eval(N)\nsize = m * n\nresult = size // 2\nprint(result)\n","(n, m) = list(map(int, input().split()))\na = 2 * 1\nsum = n * m\nprint(sum // a)\n","(m, n) = map(int, input().split())\nfinal = 0\narea = m * n\nif area >= 2:\n\tfinal = area // 2\nprint(final)\n","NM = list(map(int, input().split()))\nprint(NM[0] * NM[1] // 2)\n","M_and_N = input()\nM_and_N = M_and_N.split(' ')\nM = int(M_and_N[0])\nN = int(M_and_N[1])\nif M % 2 == 0:\n\tnum = M // 2 * N\nelse:\n\tnum = M // 2 * N + N // 2\nprint(num)\n","num = input().split(' ')\nfor i in range(len(num)):\n\tnum[i] = int(num[i])\nm = num[0]\nn = num[1]\nprint(m * n // 2)\n","import math\n(m, n) = input().split()\nm = int(m)\nn = int(n)\na = m * n\nans = a / 2\nval = math.floor(ans)\nprint(val)\n","(M, N) = map(int, input().split())\na = 2\ns = M % a\nif s == 0:\n\tprint(M // a * N)\nif s != 0:\n\tm = N // 2\n\ttotal = M // a * N + m\n\tprint(total)\n","(m, n) = map(int, input().split())\na = m * n\nfinal = a // 2\nprint(final)\n","(n, k) = map(int, input().split())\nh = min(n, k)\nw = max(n, k)\nres = h * (w // 2)\nif w % 2 != 0:\n\tres += h // 2\nprint(res)\n","A = input().split(' ')\nB = [int(elem) for elem in A]\n(n, m) = (B[0], B[1])\nprint(int(n * m / 2))\n","(m, n) = map(int, input().split())\nk = 0\nk = m * n // 2\nprint(k)\n","(a, b) = input().split()\n(a, b) = (int(a), int(b))\nx = a * b\nif x % 2 == 1:\n\tx -= 1\nx /= 2\nprint(int(x))\n","def domino():\n\t(n, m) = map(int, input().split())\n\tx = n * m\n\tdom = 0\n\tif x % 2 == 0:\n\t\tdom = int(x / 2)\n\telse:\n\t\tdom = int((x - 1) / 2)\n\tprint(dom)\ndomino()\n","import math\ninputNums = input()\nq = []\nfor i in inputNums.split(' '):\n\tq.append(i)\nm = int(q[0])\nn = int(q[1])\nprint(math.floor(m * n / 2))\n","(l, w) = map(int, input().split())\narea = l * w\ndominoes = area // 2\nprint(str(dominoes))\n","def inp_m_n():\n\tm_n = input()\n\tm_n = list(m_n.split(' '))\n\tm_n = list(map(int, m_n))\n\treturn m_n\nm_n = inp_m_n()\nm = m_n[0]\nn = m_n[1]\nN = m * n // 2\nprint(N)\n","(m, n) = map(int, input().split())\nd = 0\ns = m * n\nprint(int(s / 2))\n","from math import floor\n\ndef main():\n\trdl = input().split()\n\tn = int(rdl[0])\n\tm = int(rdl[1])\n\ts = n * m\n\tprint(floor(s / 2))\nmain()\n","t = [int(x) for x in input().split()]\nres = 0\nif t[0] > 1 and t[1] > 1:\n\tif t[0] % 2 == 0:\n\t\tres = int(t[0] / 2 * t[1])\n\telif t[1] % 2 == 0:\n\t\tres = int(t[1] / 2 * t[0])\n\telse:\n\t\tres = int(t[0] / 2) * t[1] + int(t[1] / 2)\nelse:\n\tt.sort()\n\tres = int(t[1] / 2)\nprint(res)\n","(rec1, rec2) = input().split()\na = int(rec1) * int(rec2)\nprint(a // 2)\n","def domino(M, N):\n\tif M != 1 and N != 1 and (M != 0) and (N != 0):\n\t\treturn M + N - 2 + domino(M - 2, N - 2)\n\telif M == 1 or N == 1:\n\t\tif N == 1:\n\t\t\treturn M // 2\n\t\telse:\n\t\t\treturn N // 2\n\telse:\n\t\treturn 0\n(M, N) = list(map(int, input().strip().split()))\nprint(domino(M, N))\n","(k, n) = [int(s) for s in input().split()]\nprint(k * n // 2)\n","from sys import stdin\n\ndef main():\n\tn = [int(x) for x in stdin.readline().strip().split()]\n\tx = n[0]\n\ty = n[1]\n\tprint(x * y // 2)\nmain()\n","(m, n) = map(int, input().split())\nfield_area = m * n\ndomino_area = 2 * 1\nprint(field_area // domino_area)\n","import sys\n\ndef get_ints():\n\treturn map(int, sys.stdin.readline().strip().split())\n(m, n) = get_ints()\nprint(int(m * n / 2))\n","(a, b) = input().split()\na = int(a)\nb = int(b)\narea = a * b\narea_of_domino = 2\nprint(area // area_of_domino)\n","import math\nmn = list(map(int, input().strip().split()))\n(r1, r2, c1, c2) = (0, 0, 0, 0)\nr1 = math.floor(mn[0] / 2)\nc1 = math.floor(mn[1] / 1)\nif mn[0] % 2 == 0:\n\tmn[0] = 0\nelse:\n\tmn[0] -= 2 * r1\nr2 = math.floor(mn[0] / 1)\nc2 = math.floor(mn[1] / 2)\nprint(r1 * c1 + r2 * c2)\n","n = list(map(int, input().split()))\nmul = n[0] * n[1]\nprint(mul // 2)\n","(row_size, col_size) = map(int, input().split())\nsquares = row_size * col_size\nprint(squares // 2)\n","a = input().split()\nn = int(max(a[0], a[1]))\nm = int(min(a[0], a[1]))\nif n % 2 != 0:\n\tx = n // 2 * m + m // 2\nelse:\n\tx = n // 2 * m\nprint(x)\n","(M, N) = input().split(' ')\nN = int(N)\nM = int(M)\nx = 0\nwhile N > 1:\n\tx = M + x\n\tN = N - 2\nwhile M > 1 and N != 0:\n\tx = x + 1\n\tM = M - 2\nprint(x)\n","try:\n\t(m, n) = input().split(' ')\n\tif int(m) >= 1 and int(m) <= 16 and (int(m) >= 1) and (int(m) <= 16):\n\t\ttotal = int(m) * int(n)\n\t\tnumber_of_puzzles = total // 2\n\t\tprint(number_of_puzzles)\nexcept Exception as e:\n\tprint(e)\n","(m, n) = map(int, input().split())\nif m < 2 and n < 2:\n\tprint(0)\nelse:\n\tq1 = m // 2\n\tq2 = m % 2\n\tprint(q1 * n + q2 * n // 2)\n","dom = input().split()\nres = int(int(dom[0]) * int(dom[1]) / 2)\nprint(res)\n","s = input().split(' ')\nfor hj in range(len(s)):\n\ts[hj] = int(s[hj])\nprint(int(s[0] * s[1] // 2))\n","import math\nstdin = input()\ndim = stdin.split(' ')\nm = int(dim[0])\nn = int(dim[1])\nsolution = math.floor(m * n * 0.5)\nprint(solution)\n","def Convert(string):\n\tli = list(string.split(' '))\n\treturn li\ndim = input()\nlisto = Convert(dim)\nfor x in range(len(listo)):\n\tlisto[x] = int(listo[x])\nm = listo[0]\nn = listo[1]\ncheck = m * n\nif check % 2 == 1:\n\tprint(int((check - 1) / 2))\nelse:\n\tprint(int(check / 2))\n","(r, c) = [int(x) for x in input().split()]\nif r <= 1 and c <= 1:\n\tprint(0)\nelse:\n\tprint(r * c // 2)\n","def NumberDominoes(M, N):\n\tcount = 0\n\tNleft = N\n\tcurrent = N // 2\n\tcount = count + current * M\n\tNleft = Nleft - current * 2\n\tif Nleft != 0:\n\t\tcurrent = M // 2\n\t\tcount = count + current\n\treturn count\n(M, N) = map(int, input().split(' '))\nprint(NumberDominoes(M, N))\n","(M, N) = map(int, input().split())\nif M * N % 2 == 0:\n\tp = M * N // 2\nelse:\n\tp = M * N // 2\nprint(p)\n","(a, b) = [int(x) for x in input().split(' ')]\ntotal_boxes = a * b\ncovered = total_boxes // 2\nprint(covered)\n","rect_area = input().split()\nl = rect_area[0]\nb = rect_area[1]\nm = int(l)\nn = int(b)\ndominoes_area = 2 * 1\nprint(m * n // dominoes_area)\n","n = list(map(int, input().split()))\nx = n[0] * n[1]\ny = x / 2\ny = int(y)\nprint(y)\n","line = input()\nm = int(line[0:line.find(' ')])\nn = int(line[line.find(' ') + 1:len(line)])\nif m % 2 == 0 and n % 2 == 0:\n\tprint(int(m * (n / 2)))\nelif m % 2 == 0 and n % 2 != 0 or (m % 2 != 0 and n % 2 == 0):\n\tprint(int(m * (n - 1) / 2 + m / 2))\nelif m % 2 != 0 and n % 2 != 0:\n\tprint(int((m * n - 1) / 2))\n","(m, n) = [int(i) for i in input().split()]\nif m % 2 == 0:\n\tprint(m // 2 * n)\nelif n % 2 == 0:\n\tprint(n // 2 * m)\nelse:\n\tmiddle = m // 2 * n\n\tborders = n // 2\n\tprint(middle + borders)\n","from collections import deque, Counter\nimport array\nfrom itertools import combinations, permutations\nfrom math import sqrt\n\ndef read_int():\n\treturn int(input().strip())\n\ndef read_int_array():\n\treturn [int(i) for i in input().strip().split(' ')]\n(n, m) = read_int_array()\nprint(n * m // 2)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\na = m * n\nfor i in range(1, 150):\n\tcurr = 2 * i\n\tc = i - 1\n\tif curr > a:\n\t\tbreak\nprint(c)\n","from sys import stdin\nfrom sys import stdout\n\ndef dominosPilling(m, n):\n\treturn int(m * n / 2)\nno_of_lines = list(map(int, str(input()).split(' ')))\nm = no_of_lines[0]\nn = no_of_lines[1]\ndata = dominosPilling(m, n)\nprint(data)\n","inpt = list(map(int, input().split()))\nM = inpt[0]\nN = inpt[1]\nprint(M * N // 2)\n","mn = [int(dim) for dim in input().split()]\nres = 2 * (mn[0] // 2) * (mn[1] // 2)\nif mn[0] % 2 != 0:\n\tres += mn[1] // 2\nif mn[1] % 2 != 0:\n\tres += mn[0] // 2\nprint(res)\n","num = list(input().split(' '))\nn = int(num[0])\nm = int(num[1])\nsum = 2\np = 0\nfor i in range(0, m * n):\n\tif sum <= m * n:\n\t\tp += 1\n\tsum += 2\nprint(p)\n","a = input()\na = a.split()\nb = list()\nfor x in a:\n\tb.append(int(x))\nc = 0\nc = b[0] * b[1] / 2\nprint(int(c))\n","def dimino(m, n):\n\ta = 2 * 1\n\tb = m * n\n\treturn int(b / a)\n(m, n) = map(int, input().split(' '))\nprint(dimino(m, n))\n","(m, n) = map(int, input().split())\nif m % 2 is 0:\n\tresult = m / 2 * n\nelif n % 2 is 0:\n\tresult = m * (n / 2)\nelse:\n\tresult = (m - 1) / 2 * n + int(n / 2)\nprint(int(result))\n","(j, k) = [int(i) for i in input().split(' ')]\nprint(j * k // 2)\n","def main():\n\t(m, n) = map(int, input().split())\n\ts = m * n\n\tif s % 2 != 0:\n\t\ts -= 1\n\tprint(int(s / 2))\nmain()\n","parameters = input()\nparam_list = list(map(int, parameters.split()))\nif param_list[0] % 2 + param_list[1] % 2 <= 1:\n\tdomino = param_list[0] * param_list[1] / 2\nelif param_list[0] == 1 and param_list[1] == 1:\n\tdomino = 0\nelif param_list[0] == 1:\n\tdomino = param_list[0] * (param_list[1] - 1) / 2\nelif param_list[1] == 1:\n\tdomino = param_list[1] * (param_list[0] - 1) / 2\nelse:\n\tdomino = param_list[0] * (param_list[1] - 1) / 2 + (param_list[0] - 1) / 2\nprint(int(domino))\n","(a, b) = input().split()\na = int(a)\nb = int(b)\nif a > b:\n\t(a, b) = (b, a)\nif a % 2 == 0:\n\tx = a // 2\n\ty = b\n\tz = x * y\nif a % 2 == 1 and a != 1:\n\tx = a // 2\n\ty = b\n\tz = x * y + b // 2\nif a == 1:\n\ty = b // 2\n\tz = y\nprint(z)\n","(m, n) = input().split()\nm = int(m)\nn = int(n)\nmaxn = max(m, n)\nminn = min(m, n)\nif maxn == 1:\n\tprint('0')\nelif maxn == 2 * minn:\n\tprint(maxn * minn // 2)\nelse:\n\tnum = maxn // 2 * minn\n\tif maxn % 2 == 0:\n\t\tprint(num)\n\telse:\n\t\tnum += minn // 2\n\t\tprint(num)\n","import sys\n(x, y) = input().split()\nx = int(x)\ny = int(y)\nc = x * y\nans = c // 2\nprint(ans)\n","(m, n) = [int(x) for x in input().split()]\ntotal = m * n // 2\nprint(total)\n"],"string":"[\n \"(M, N) = map(int, input().split())\\nd = M * N // 2\\nprint(d)\\n\",\n \"a = list(map(int, input().split()))\\na = a[1] * a[0]\\nprint(a // 2)\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nq = N % 2\\nw = N // 2\\nif q == 0:\\n\\ts = w * M\\nelse:\\n\\tc = M // 2\\n\\ts = c + w * M\\nprint(s)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\tprint(int(n * (m / 2)))\\nelse:\\n\\tprint(int(n * (m // 2) + n // 2))\\n\",\n \"def Domino(m, n):\\n\\tS = m * n\\n\\tx = S // 2\\n\\treturn x\\n(m, n) = list(map(int, input().split(' ')))\\nprint(Domino(m, n))\\n\",\n \"(a, c) = map(int, input().split(' '))\\nprint(a * c // 2)\\n\",\n \"lol = [int(i) for i in input().split()]\\na = lol[0]\\nb = lol[1]\\nprint(a * b // 2)\\n\",\n \"(m, n) = [int(i) for i in input().split(' ')]\\nif m % 2 == 0:\\n\\tprint(int(n * (m / 2)))\\nelif n % 2 == 0:\\n\\tprint(int(m * (n / 2)))\\nelse:\\n\\tprint(int(n * ((m - 1) / 2) + n // 2))\\n\",\n \"from math import trunc\\n(M, N) = [int(s) for s in input().split(' ')]\\nprint(trunc(M * N / 2))\\n\",\n \"inp = input()\\ninp = inp.split(' ')\\nnum_squares = int(inp[0]) * int(inp[1])\\nprint(int(num_squares / 2))\\n\",\n \"(m, n) = map(int, input().split())\\na = max(m, n)\\nb = min(m, n)\\np = a // 2 * b\\nif a % 2 != 0:\\n\\tp = p + b // 2\\nprint(p)\\n\",\n \"x = input().split()\\np = int(x[0]) * int(x[1])\\nif p % 2 == 0:\\n\\tprint(p // 2)\\nif p % 2 != 0:\\n\\tprint((p - 1) // 2)\\n\",\n \"(w, h) = input().split()\\nw = int(w)\\nh = int(h)\\nif w % 2 == 0:\\n\\ttotal = w / 2 * h\\nelif h % 2 == 0:\\n\\ttotal = h / 2 * w\\nelse:\\n\\ttotal = (w - 1) / 2 * h + int(h / 2)\\nprint(int(total))\\n\",\n \"arr = input().split()\\nprint(int(arr[0]) * int(arr[1]) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0 and n % 2 == 0:\\n\\tprint(int(m / 2 * (n / 1)))\\nelif m % 2 == 0 and n % 2 != 0:\\n\\tprint(int(m / 2 * n))\\nelif m % 2 != 0 and n % 2 == 0:\\n\\tprint(int(n / 2 * m))\\nelif m % 2 != 0 and n % 2 != 0:\\n\\tprint(int(int(m / 2) * int(n - 1) + int(m / 2) + int(n / 2)))\\n\",\n \"(n, m) = map(int, input().split())\\nprint(int(n * m / 2))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\na = m * n\\nnumber = int(a / 2)\\nprint(number)\\n\",\n \"ip = input()\\nargs = ip.split(' ')\\nM = int(args[0])\\nN = int(args[1])\\narea = M * N\\nans = 0\\noneMax = int(M / 2)\\nans = oneMax * N\\nif oneMax * 2 < M:\\n\\tans += int(N / 2)\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split(' '))\\ntotal_square = m * n\\nif total_square % 2 == 0:\\n\\tprint(int(total_square / 2))\\nelse:\\n\\tprint(int((total_square - 1) / 2))\\n\",\n \"a = input().split(' ')\\nm = int(a[0])\\nn = int(a[1])\\nprint(int(m * n / 2))\\n\",\n \"(m, n) = map(int, input().split())\\n(m, r) = divmod(m, 2)\\nprint(m * n + n // 2 * r)\\n\",\n \"lisa = input()\\nindex = 0\\nfor i in range(len(lisa)):\\n\\tif lisa[i] == ' ':\\n\\t\\tindex = i\\nprint(int(int(lisa[0:index]) * int(lisa[index + 1:len(lisa)]) / 2))\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\narea = M * N\\nprint(area // 2)\\n\",\n \"line = input()\\na = line.split()\\nx = int(a[0])\\ny = int(a[1])\\ns = x * y\\nif s % 2 == 0:\\n\\tprint(int(s / 2))\\nelse:\\n\\tprint(int((s - 1) / 2))\\n\",\n \"import math\\n(m, n) = list(map(int, str(input()).split()))\\nprint(math.floor(m * n / 2))\\n\",\n \"line = input().split()\\nprint(int(line[0]) * int(line[1]) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nh = n * int(m / 2)\\nv = 0\\nif m % 2 == 1:\\n\\tv = n / 2\\nprint(int(h + v))\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef insr():\\n\\ts = input()\\n\\treturn list(s[:len(s) - 1])\\n\\ndef invr():\\n\\treturn map(int, input().split())\\n(n, k) = inlt()\\ns = int(k * n / 2)\\nprint(s)\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\nn = a * b // 2\\nprint(math.ceil(n))\\n\",\n \"import sys\\nONLINE_JUDGE = __debug__\\nif ONLINE_JUDGE:\\n\\tinput = sys.stdin.readline\\nelse:\\n\\tsys.stdin = open('ip.txt', 'r')\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef insr():\\n\\ts = input()\\n\\treturn list(s[:len(s) - 1])\\n\\ndef invr():\\n\\treturn map(int, input().split())\\n(M, N) = invr()\\nprint(int(M * N / 2))\\n\",\n \"x = input()\\nx = x.split(' ')\\ny = int(x[0]) * int(x[1])\\nprint(y // 2)\\n\",\n \"t = input().split()\\nprint(int(int(t[0]) * int(t[1]) / 2))\\n\",\n \"q = input()\\nprint(int(q.split(' ')[0]) * int(q.split(' ')[1]) // 2)\\n\",\n \"line = input().split(' ')\\n(a, b) = line\\na = int(a)\\nb = int(b)\\nc = a * b / 2\\nc = int(c)\\nprint('%d' % c)\\n\",\n \"(w, l) = map(int, input().split())\\no = int(w * l / 2)\\nprint(o)\\n\",\n \"(a, b) = tuple(map(int, input().split()))\\nprint(a * b // 2)\\n\",\n \"from math import floor\\n(M, N) = map(int, input().split())\\nprint(floor(M * N / 2))\\n\",\n \"def main(inp):\\n\\tprod = inp[0] * inp[1]\\n\\tif prod % 2 == 0:\\n\\t\\treturn int(prod / 2)\\n\\telse:\\n\\t\\treturn int((prod - 1) / 2)\\ninp = list(map(int, input().split(' ')))\\nprint(main(inp))\\n\",\n \"n = list(map(int, input().split(' ')))\\nm = n[1]\\nn = n[0]\\nprint(m * n // 2)\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nou = int(M * N / 2)\\nprint(ou)\\n\",\n \"(a, b) = map(int, input().split())\\nif a * b % 2 == 0:\\n\\tz = a * b / 2\\nelif a * b % 2 == 1:\\n\\tz = (a * b - 1) / 2\\nprint(int(z))\\n\",\n \"(a, b) = map(int, input().split())\\nm = a * b\\nif m % 2 == 0:\\n\\tprint(int(m / 2))\\nelse:\\n\\tprint(int((m - 1) / 2))\\n\",\n \"import math\\n(A, B) = map(int, input().split())\\n\\ndef C(m, n):\\n\\tA = m * n\\n\\treturn math.floor(A / 2)\\nprint(C(A, B))\\n\",\n \"def solve():\\n\\t(n, m) = [int(s) for s in input().split()]\\n\\tprint(n * m // 2)\\nsolve()\\n\",\n \"m = input()\\nm = m.split(' ')\\nc = int(m.pop(), 10)\\nf = int(m.pop(), 10)\\nif f % 2 == 0:\\n\\tprint(int(f * c / 2))\\nelse:\\n\\tprint(int(f * (c - 1) / 2 + f / 2))\\n\",\n \"s = input()\\n(n, m) = s.split()\\nn = int(n)\\nm = int(m)\\nif n % 2 == 0 or m % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"data = input().split()\\nM = int(data[0])\\nN = int(data[1])\\nprint((M - M % 2) * (N - N % 2) // 2 + M % 2 * (N // 2) + N % 2 * (M // 2))\\n\",\n \"mn = input().split(' ')\\nm = int(mn[0])\\nn = int(mn[1])\\nprint(m * n // 2)\\n\",\n \"line = input()\\n(m, n) = line.split()\\nm = int(m)\\nn = int(n)\\na = max(m, n)\\nb = min(m, n)\\nif a % 2 == 0:\\n\\tans = a * b / 2\\nelif b % 2 == 0:\\n\\tans = (a - 1) * b / 2 + b / 2\\nelse:\\n\\tans = (a - 1) * b / 2 + (b - 1) / 2\\nans = int(ans)\\nprint(ans)\\n\",\n \"inp = list(map(int, input().split()))\\nprint(int(inp[0] * inp[1] / 2))\\n\",\n \"def solve(m, n):\\n\\tdominoes = 0\\n\\twhile m > 1:\\n\\t\\tdominoes += n\\n\\t\\tm -= 2\\n\\tif m > 0:\\n\\t\\tdominoes += n // 2\\n\\treturn dominoes\\nprint(solve(*[int(i) for i in input().split(' ')]))\\n\",\n \"line = input().split()\\na = int(line[0])\\nb = int(line[1])\\nif b % 2 == 0:\\n\\toutcome = a * (b / 2)\\n\\tprint(int(outcome))\\nelse:\\n\\tb = b - 1\\n\\tif a % 2 == 0:\\n\\t\\toutcome = a * (b / 2) + a / 2\\n\\telse:\\n\\t\\toutcome = a * (b / 2) + (a - 1) / 2\\n\\tprint(int(outcome))\\n\",\n \"M = input()\\nN = M[M.find(' ') + 1:]\\nM = int(M[:M.find(' ')])\\nN = int(N)\\nprint(M * N // 2)\\n\",\n \"print(int.__mul__(*map(int, input().split())) // 2)\\n\",\n \"temp = input()\\n(m, n) = temp.split(' ')\\nm = int(m)\\nn = int(n)\\ndomino = 2\\nboard = m * n\\nprint(int(board / domino))\\n\",\n \"mn = input().split()\\nm = int(mn[0])\\nn = int(mn[1])\\na = m * n\\nout = a // 2\\nprint(out)\\n\",\n \"(m, n) = map(int, input().split())\\na = 2 * 1\\nb = m * n\\nprint(int(b / a))\\n\",\n \"from math import floor\\n(n, m) = list(map(int, input().split()))\\nprint(floor(m * n * 0.5))\\n\",\n \"(a, b) = map(int, input().split())\\nif a != 0 and b != 0:\\n\\tprint(a * b // 2)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nproduct = m * n / 2\\nprint(math.floor(product))\\n\",\n \"def checker(num):\\n\\treturn int(int(num[0]) * int(num[1]) / 2)\\nprint(checker(input().split()))\\n\",\n \"data = list(map(int, input().split()))\\nm = data[0]\\nn = data[1]\\nif m % 2 == 0:\\n\\tprint(int(m / 2 * n))\\nelse:\\n\\tprint(int(n / 2 * m))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nprint(str(int(m * n / 2)))\\n\",\n \"(i, j) = input().split(' ')\\ni = int(i)\\nj = int(j)\\nh = i // 2\\nh = h * j\\nif i % 2 == 0:\\n\\tprint(h)\\nelse:\\n\\tm = j // 2\\n\\tm = m + h\\n\\tprint(m)\\n\",\n \"inputs = input().split(' ')\\nm = int(inputs[0])\\nn = int(inputs[1])\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\tprint(int(m * n / 2))\\n\\texit()\\nif n % 2 == 0:\\n\\tprint(int(m * n / 2))\\n\\texit()\\nprint(int((m * n - 1) / 2))\\n\",\n \"x = input().split()\\nfor i in range(len(x)):\\n\\tx[i] = int(x[i])\\ny = x[0] * x[1]\\nres = y / 2\\nif y % 2 != 0:\\n\\tres = y // 2\\nprint(int(res))\\n\",\n \"import math\\ndt = list(map(lambda x: int(x), input().split(' ')))\\n(n, m) = (dt[0], dt[1])\\nprint(max(math.floor(n / 2 * m / 1), math.floor(n / 1 * m / 2)))\\n\",\n \"import math\\ninp = input().split()\\nm = int(inp[0])\\nn = int(inp[1])\\nprint(math.floor(m * n / 2))\\n\",\n \"a = input().split()\\n(b, c) = (int(a[0]), int(a[1]))\\nif b % 2 and c % 2:\\n\\tprint(int((b * c - 1) / 2))\\nelse:\\n\\tprint(int(b * c / 2))\\n\",\n \"from math import floor\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nprint(floor(m * n / 2))\\n\",\n \"import math\\n(M, N) = input().split()\\nanswer = 0\\nanswer = int(M) * int(N)\\nanswer = math.floor(answer / 2)\\nprint(answer)\\n\",\n \"s = input().split(' ')\\na = int(int(s[0]) * int(s[1]) / 2)\\nprint(a)\\n\",\n \"(M, N) = map(int, input().split())\\narea = M * N\\nanswer = area // 2\\nprint(answer)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nn = M * N\\nprint(int(n / 2))\\n\",\n \"(n, m) = map(int, input().split())\\nx = n * m\\noutput = x // 2\\nprint(output)\\n\",\n \"import math\\n(row, col) = map(int, input().split())\\nsizing = row * col\\nif sizing % 2 == 0:\\n\\tamount = sizing / 2\\nelse:\\n\\tamount = math.floor(sizing / 2)\\nprint(int(amount))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nmult = M * N\\nprint(int(mult / 2))\\n\",\n \"[m, n] = list(map(int, input().split(' ')))\\nif m == 0 or n == 0:\\n\\tprint(0)\\nif m == 1 and n == 1:\\n\\tprint(0)\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"(M, N) = map(int, input().strip().split())\\ncnt = 0\\nif M >= 2:\\n\\tcnt += M // 2 * N\\n\\tif M % 2:\\n\\t\\tif N > 1:\\n\\t\\t\\tprint(N // 2 + cnt)\\n\\t\\telse:\\n\\t\\t\\tprint(cnt)\\n\\telse:\\n\\t\\tprint(cnt)\\nelif N > 1:\\n\\tprint(N // 2)\\nelse:\\n\\tprint(0)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nd = 0\\nif m % 2 == 0:\\n\\td = n * (m // 2)\\nelif n % 2 == 0:\\n\\td = m * (n // 2)\\nelse:\\n\\td = n * (m // 2) + n // 2\\nprint(d)\\n\",\n \"(m, h) = lst = list(map(int, input().split(' ')))\\nprint(m * h // 2)\\n\",\n \"import math\\n\\ndef main():\\n\\ti = input().split()\\n\\tm = int(i[0])\\n\\tn = int(i[1])\\n\\tout = math.floor(n * m / 2)\\n\\tprint(out)\\nmain()\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif N * M % 2 == 0:\\n\\tprint(int(N * M / 2))\\nelse:\\n\\tprint(int((N * M - 1) / 2))\\n\",\n \"(a, b) = [int(i) for i in input().split()]\\nprint(int(a * b / 2))\\n\",\n \"def domino(n):\\n\\tarea = n[0] * n[1]\\n\\tif area % 2 == 0:\\n\\t\\treturn int(area / 2)\\n\\telse:\\n\\t\\treturn int((area - 1) / 2)\\nn = list(map(int, input().split(' ')))\\nans = domino(n)\\nprint(ans)\\n\",\n \"(n, m) = map(lambda x: int(x), input().split())\\nans = int(n * m / 2.0)\\nprint(ans)\\n\",\n \"f = input().split()\\nm = int(f[0])\\nn = int(f[1])\\nM = m * n\\nN = M // 2\\nprint(N)\\n\",\n \"li = list(map(int, input().split()))\\nm = li[0]\\nn = li[1]\\nres = int(m * n / 2)\\nprint(res)\\n\",\n \"(m, n) = input().split()\\ns = int(m) * int(n)\\nprint(s // 2)\\n\",\n \"def pomnozi_listu(lista):\\n\\tiznos = 1\\n\\tfor x in lista:\\n\\t\\tiznos *= x\\n\\treturn iznos\\nbroj = input()\\npovrsina = broj.split()\\nfor i in range(0, len(povrsina)):\\n\\tpovrsina[i] = int(povrsina[i])\\nif pomnozi_listu(povrsina) % 2 == 0:\\n\\tprint(pomnozi_listu(povrsina) // 2)\\nelif pomnozi_listu(povrsina) % 2 == 1:\\n\\tprint((pomnozi_listu(povrsina) - 1) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\ndominoes = area // 2\\nprint(dominoes)\\n\",\n \"import sys\\n\\ndef max_dominos(a, b):\\n\\tif max(a, b) < 2:\\n\\t\\treturn 0\\n\\tm = max(a, b)\\n\\tn = min(a, b)\\n\\tif m % 2 and n % 2:\\n\\t\\treturn max_dominos(m - 1, n) + max_dominos(n, 1)\\n\\telse:\\n\\t\\treturn int(n * m / 2)\\n\\ndef main():\\n\\tinput = sys.stdin.readline()\\n\\t(m, n) = map(int, input.split())\\n\\tprint(max_dominos(m, n))\\nmain()\\n\",\n \"board_size = [int(i) for i in input().split()]\\nif board_size[0] >= 2:\\n\\tif board_size[0] % 2 == 0:\\n\\t\\tprint(board_size[0] // 2 * board_size[1])\\n\\telif board_size[1] % 2 == 0:\\n\\t\\tprint(board_size[1] // 2 * board_size[0])\\n\\telse:\\n\\t\\tprint(board_size[0] // 2 * board_size[1] + board_size[1] // 2)\\nelif board_size[0] == 1 and board_size[1] >= 2:\\n\\tprint(board_size[1] // 2)\\nelse:\\n\\tprint('0')\\n\",\n \"(m, n) = str(input()).split()\\nm = int(m)\\nn = int(n)\\nif 1 <= m and m <= n and (n <= 16):\\n\\tprint(int(m * n // 2))\\n\",\n \"n_m = input()\\nn_m = n_m.split()\\nN = int(n_m[0])\\nM = int(n_m[1])\\nnumber_of_dominoes = int(N * M / 2)\\nprint(number_of_dominoes)\\n\",\n \"(x, y) = map(int, input().strip().split())\\nprint(x * y // 2)\\n\",\n \"(M, N) = [int(item) for item in input().split(' ')]\\nprint(M * N // 2)\\n\",\n \"l = input().split()\\nM = int(l[0])\\nN = int(l[1])\\nn = int(M * N / 2)\\nprint(n)\\n\",\n \"rectangle_size = input().split()\\nm = int(rectangle_size[0])\\nn = int(rectangle_size[1])\\ndominos = m * n // 2\\nprint(dominos)\\n\",\n \"(m, n) = input().split()\\ntotal_spaces = int(m) * int(n)\\nmax_dominoes = int(total_spaces / 2)\\nprint(max_dominoes)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nx = m * n // 2\\nprint(x)\\n\",\n \"def dp(m, n):\\n\\ttileArea = 2 * 1\\n\\tboardArea = m * n\\n\\treturn boardArea // tileArea\\n(m, n) = map(int, input().split())\\nprint(dp(m, n))\\n\",\n \"import math\\nlimit = input('').strip()\\na = []\\ncount = 0\\nfor i in range(0, len(limit)):\\n\\tif limit[i] == ' ':\\n\\t\\ta.append(int(limit[int(count):int(i)]))\\n\\t\\tcount = i + 1\\n\\telif i == len(limit) - 1:\\n\\t\\ta.append(int(limit[int(count):len(limit)]))\\none_side = math.floor(a[0] / 2)\\nother_side = a[1]\\nresult = one_side * other_side + math.floor(a[1] * (a[0] % 2) / 2)\\nprint(result)\\n\",\n \"import math\\n(m, n) = map(int, input().split(' '))\\ns = m * n\\nt = math.floor(s / 2)\\nprint(t)\\n\",\n \"[M, N] = [int(x) for x in input().split()]\\nnmax = 0\\nif M == 1:\\n\\tnmax = N // 2\\nif M > 1:\\n\\ta = M // 2\\n\\tif N == 1:\\n\\t\\tnmax = a\\n\\tif N > 1:\\n\\t\\tB0 = M % 2\\n\\t\\tb = N // 2\\n\\t\\tnmax = a * N + b * B0\\nprint(nmax)\\n\",\n \"(n, m) = map(int, input().split())\\nif m % 2 == 1:\\n\\tprint(n * (m // 2) + n // 2)\\nelse:\\n\\tprint(n * (m // 2))\\n\",\n \"(n, k) = [int(x) for x in input().split()]\\nm = int(n / 2)\\ncount = m * k + n % 2 * int(k / 2)\\nprint(count)\\n\",\n \"board_dimensions = input('').split()\\n(row, col) = board_dimensions\\nm = int(row)\\nn = int(col)\\nlast_col = 0\\ndimension_domino = [2, 1]\\nif m % 2 == 0:\\n\\tper_row = m / 2\\nelse:\\n\\tper_row = (m - 1) / 2\\n\\tif n % 2 == 0:\\n\\t\\tlast_col = n / 2\\n\\telse:\\n\\t\\tlast_col = (n - 1) / 2\\ntotal_dominoes = per_row * n + last_col\\nprint(int(total_dominoes))\\n\",\n \"s = input()\\nss = s.split(' ')\\nlen = float(ss[0]) / 2\\nsum = len * float(ss[1])\\nprint(int(sum))\\n\",\n \"(m, n) = [int(v) for v in input().split(' ')]\\nr = m * n\\nif r % 2 == 0:\\n\\tprint(r // 2)\\nelse:\\n\\tprint((r - 1) // 2)\\n\",\n \"line = input()\\nm = int(line.split()[0])\\nn = int(line.split()[1])\\nprint(m * n // 2)\\n\",\n \"import math\\n(m, n) = [int(i) for i in input().split(' ')]\\nh = math.floor(m / 2) * n\\nif m % 2:\\n\\th += math.floor(n / 2)\\nv = math.floor(n / 2) * m\\nif n % 2:\\n\\tv += math.floor(m / 2)\\nprint('%d' % max(v, h))\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nA = M * N\\nif A % 2 == 0:\\n\\tprint(int(A / 2))\\nelse:\\n\\tprint(int(math.floor(A / 2)))\\n\",\n \"x = list(map(int, input().split()))\\nprint(x[0] * x[1] // 2)\\n\",\n \"ch = input().split()\\nn = int(ch[0])\\nm = int(ch[1])\\nprint(n * m // 2)\\n\",\n \"game_board = input().split()\\nX = int(game_board[0])\\nY = int(game_board[1])\\nboard_size = X * Y\\nif board_size % 2 == 0:\\n\\tans1 = board_size / 2\\n\\tprint(int(ans1))\\nelse:\\n\\tans2 = (board_size - 1) / 2\\n\\tprint(int(ans2))\\n\",\n \"import math\\n(W, L) = map(int, input().split())\\nX = W * L / 2\\nout = math.floor(X)\\nprint(out)\\n\",\n \"(n, m) = input().split()\\n(n, m) = (int(n), int(m))\\nc = n * m\\nprint(c // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nc = a * b\\nd = c % 2\\nc = c - d\\nprint(int(c // 2))\\n\",\n \"(m, n) = [int(elem) for elem in input().split()]\\nprint(n * (m // 2) + n // 2 * (m % 2))\\n\",\n \"import sys\\n(n, m) = [int(item) for item in sys.stdin.readline().split(' ')]\\nif n % 2 == 0:\\n\\ta = n / 2 * m\\nelif m % 2 == 0:\\n\\ta = m / 2 * n\\nelse:\\n\\ta = n // 2 * m + m // 2\\nprint(int(a))\\n\",\n \"(a, b) = list(map(int, input().rstrip().split()))\\nprint(a * b // 2)\\n\",\n \"import math\\nn = list(map(int, input().split()))\\nr = math.floor(n[0] * n[1] / 2)\\nprint(r)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nd = m * n // 2\\nprint(d)\\n\",\n \"s = input().split()\\n(m, n) = (int(s[0]), int(s[1]))\\nprint(m * n // 2)\\n\",\n \"import sys\\n(m, n) = sys.stdin.readline().strip().split()\\nn = int(n)\\nm = int(m)\\nif m % 2 == 0 or n % 2 == 0:\\n\\tresult = m * n / 2\\nelse:\\n\\tresult = (m - 1) * n / 2 + (n - 1) / 2\\nresult = int(result)\\nprint(result)\\n\",\n \"nums = input().split(' ')\\nnums = [int(x) for x in nums]\\nres = nums[0] * nums[1]\\nif res % 2 == 0:\\n\\tprint(int(res / 2))\\nelse:\\n\\tprint(int((res - 1) / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nif m > n:\\n\\t(m, n) = (n, m)\\ndom = 0\\nif m == 1 and n == 1:\\n\\tprint(0)\\nelse:\\n\\tdom = m * (n // 2)\\n\\tif n % 2 != 0:\\n\\t\\tdom += m // 2\\n\\tprint(dom)\\n\",\n \"import math\\n(N, M) = [int(x) for x in input().split()]\\nd = int(math.floor(N * M / 2))\\nprint(d)\\n\",\n \"a = input().split()\\nm = int(a[0])\\nn = int(a[1])\\nboardsize = m * n\\ndomino = 2\\nmaxdomino = boardsize // domino\\nprint(maxdomino)\\n\",\n \"size = [int(i) for i in input().split()]\\narea = size[0] * size[1]\\nnumb_dominos = int(area / 2)\\nprint(numb_dominos)\\n\",\n \"(x, y) = (int(i) for i in input().split())\\nprint(int(x * y / 2))\\n\",\n \"(a, b) = tuple((int(x) for x in input().split(' ')))\\nt = a * b\\nresult = t // 2\\nprint(result)\\n\",\n \"MN = input().split(' ')\\nM = int(MN[0])\\nN = int(MN[1])\\nprint(M * N // 2)\\n\",\n \"import sys\\n(a, b) = [int(s) for s in input().strip().split()]\\nprint(a * b // 2)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nnum = m * n // 2\\nprint(num)\\n\",\n \"n = input()\\nn = n.split(' ')\\nprint(int(n[0]) * int(n[1]) // 2)\\n\",\n \"line = input()\\nspieces = line.split()\\nm = int(spieces[0])\\nn = int(spieces[1])\\nif m % 2 != 0 and n % 2 != 0:\\n\\tt = int((m * n - 1) / 2)\\nelse:\\n\\tt = int(m * n / 2)\\nprint(t)\\n\",\n \"(x, y) = map(int, input().split())\\narea = x * y\\ncounter = int(area / 2)\\nprint(counter)\\n\",\n \"import math\\ninputs = list(map(lambda x: int(x), input().split()))\\nprint(math.floor(inputs[0] * inputs[1] / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nx = m / 2\\ny = n / 1\\nprint(int(x * y))\\n\",\n \"a = [] * 2\\na = [int(i) for i in input().split()]\\ns = a[0] * a[1]\\nprint(s // 2)\\n\",\n \"import sys as s\\noutpt = 0\\nfor v in s.stdin:\\n\\tv = v.strip().split()\\n\\tif len(v) != 2:\\n\\t\\texit(1)\\n\\telse:\\n\\t\\tprint(int(v[0]) * int(v[1]) // 2)\\n\\t\\texit(0)\\nexit(1)\\n\",\n \"(m, n) = list(map(int, input().split()))\\narea = m * n\\nno = area // 2\\nprint(no)\\n\",\n \"ar = [int(n) for n in input().split()]\\nprint(ar[0] * ar[1] // 2)\\n\",\n \"(m, n) = input().split()\\n(m, n) = (int(m), int(n))\\narea = m * n\\nprint(area // 2)\\n\",\n \"import time\\n\\nclass Profiler(object):\\n\\n\\tdef __enter__(self):\\n\\t\\tself._startTime = time.time()\\n\\n\\tdef __exit__(self, type, value, traceback):\\n\\t\\tprint('Elapsed time: {:.3f} sec'.format(time.time() - self._startTime))\\n(m, n) = list(map(int, input().split()))\\nm2 = m // 2 * 2\\nn2 = n // 2 * 2\\ncount = m2 * n2 // 2\\ncount += (m - m2) * n2 // 2\\ncount += (n - n2) * m2 // 2\\nprint(count)\\n\",\n \"a = []\\na = list(map(int, input().split()))\\nl = a[1]\\nw = a[0]\\nans = 0\\nwhile w >= 0:\\n\\tif w >= 2:\\n\\t\\tans += l\\n\\telif w == 1:\\n\\t\\tans += l // 2\\n\\tw = w - 2\\nprint(ans)\\n\",\n \"t = input()\\nt = list(map(int, t.split()))\\nm = t[0]\\nn = t[1]\\nif m % 2 == 0:\\n\\td = m // 2 * n\\nelif n % 2 == 0:\\n\\td = n // 2 * m\\nelse:\\n\\td = m // 2 * n + n // 2\\nprint(d)\\n\",\n \"str = input().split(' ')\\n(M, N) = [int(x) for x in str]\\ntotal = M // 2 * N + M % 2 * (N // 2)\\nprint(total)\\n\",\n \"import math\\nimport os\\nimport random\\nimport re\\nimport sys\\n(m, n) = list(map(int, input().split()))\\nprint(int(m * n / 2))\\n\",\n \"inp = input()\\nM = int(inp.split()[0])\\nN = int(inp.split()[1])\\ndesk = M * N\\ni = desk // 2\\nprint(i)\\n\",\n \"p = input()\\np2 = p.split()\\np1 = [int(p2[i]) for i in range(2)]\\nprint(p1[0] * p1[1] // 2)\\n\",\n \"import math\\nline = input()\\n(n, m) = line.split()\\nn = int(n)\\nm = int(m)\\nresult = math.floor(n * m / 2)\\nprint(result)\\n\",\n \"string = [int(x) for x in str(input()).split()]\\nprint(int(string[0] * string[1] / 2))\\n\",\n \"line = input().split(' ')\\nsize = int(line[0]) * int(line[1])\\nprint(int(size / 2) if size > 1 else 0)\\n\",\n \"import math\\na = input().split()\\nm = int(a[0])\\nn = int(a[1])\\ns = m * n\\nprint(math.floor(s / 2))\\n\",\n \"(x, y) = map(int, input().split())\\nz = x * y // 2\\nprint(z)\\n\",\n \"F = lambda : map(int, input().split())\\n(m, n) = F()\\narea = m * n\\nif area % 2 == 0:\\n\\tprint(int(area / 2))\\nelse:\\n\\tprint(int((area - 1) / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\narea = m * n\\ndomino = 2\\nif area % domino == 0:\\n\\tprint(area // domino)\\nelse:\\n\\tprint(math.floor(area // domino))\\n\",\n \"(k, l) = [int(x) for x in input().split()]\\nprint(k * l // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nm1 = m // 2 * n + m % 2 * n // 2\\nm2 = n // 2 * m + n % 2 * m // 2\\nprint(max(m1, m2))\\n\",\n \"(m, n) = input().split()\\np = int(m) * int(n)\\nprint(p // 2)\\n\",\n \"numbers = input().split(' ')\\ncapacity = int(numbers[0]) * int(numbers[1])\\nif capacity % 2 == 0:\\n\\tprint(int(capacity / 2))\\nelse:\\n\\tprint(int((capacity - 1) / 2))\\n\",\n \"(s, r) = input().split()\\ng = int(s) * int(r)\\nprint(g // 2)\\n\",\n \"(m, n) = map(int, input().split())\\ndistance = n * m\\nif m <= n and (m >= 1 and m <= 16) and (n <= 16 and n >= 1):\\n\\tresult = distance // 2\\n\\tprint(result)\\nelse:\\n\\tprint('exite')\\n\\tpass\\n\",\n \"(l, m) = map(int, input().split())\\nprint(l * m // 2)\\n\",\n \"(n, k) = map(int, input().split())\\nif n * k % 2 == 0:\\n\\tprint(int(n * k / 2))\\nelse:\\n\\tprint(int(n * k) // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nif M == 1 and N == 1:\\n\\tprint(0)\\nelse:\\n\\tprint(M * N // 2)\\n\",\n \"import math\\n(r, c) = [int(x) for x in input().split()]\\nprint(str(math.floor(r * c * 0.5)))\\n\",\n \"(n, k) = map(int, input().split())\\nc = n * k // 2\\nprint(c)\\n\",\n \"s = input()\\ns = s.split()\\nc = 0\\nc = int(int(s[1]) / 2) * int(s[0])\\nc = c + int(int(s[1]) % 2) * int(int(s[0]) / 2)\\nprint(int(c))\\n\",\n \"data = input()\\n(m, n) = data.split(' ')\\nm = int(m)\\nn = int(n)\\nsizeOfBoard = m * n\\nresult = sizeOfBoard // 2\\nprint(result)\\n\",\n \"mn = list(map(int, input().strip().split()))\\narea = mn[0] * mn[1]\\nresult = int(area / 2)\\nprint(result)\\n\",\n \"def domino(n):\\n\\treturn n // 2\\n\\ndef main():\\n\\t(l, L) = map(int, input().split())\\n\\tprint(domino(l * L))\\nmain()\\n\",\n \"(M, N) = list(map(int, input().split()))\\nprint(M * N // 2)\\n\",\n \"(w, h) = [int(x) for x in input().split()]\\ndominoes = w * h // 2\\nprint(dominoes)\\n\",\n \"tab = input()\\np = ''\\nwhile tab != '':\\n\\tc = tab[0]\\n\\tif c in ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']:\\n\\t\\tp = p + c\\n\\telse:\\n\\t\\tM = int(p)\\n\\t\\tp = ''\\n\\tif len(tab) > 1:\\n\\t\\ttab = tab[1:]\\n\\telse:\\n\\t\\ttab = ''\\n\\t\\tN = int(p)\\nnum = M * N\\ndiv = num // 2\\nprint(div)\\n\",\n \"b = input()\\nb = b.split()\\na = int(b[0])\\nb = int(b[1])\\na = a * b\\nif a % 2 == 0:\\n\\tprint(int(a / 2))\\nelse:\\n\\tb = a % 2\\n\\ta = a - b\\n\\ta = a / 2\\n\\tprint(int(a))\\n\",\n \"from math import floor\\nm = input().split()\\nprint(floor(int(m[0]) * int(m[1]) / 2))\\n\",\n \"(x, y) = (int(x) for x in input().split())\\nif x * y % 2 == 0:\\n\\tprint(x * y // 2)\\nelse:\\n\\tprint(x * y // 2)\\n\",\n \"def main():\\n\\tfrom math import floor\\n\\t(M, N) = input().split()\\n\\t(M, N) = (int(M), int(N))\\n\\tprint(floor(M / 1 * (N / 2)))\\nmain()\\n\",\n \"from math import floor\\n(A, B) = [int(i) for i in input().split(' ')]\\nprint(floor(A * B / 2))\\n\",\n \"(n, k) = input().split()\\nprint(int(int(n) * int(k) / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split(' '))\\nmap_size = m * n\\nprint(math.floor(map_size / 2))\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\nprint(a * b // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nans = m * n // 2\\nprint(str(ans))\\n\",\n \"(one, two) = map(int, input().split())\\ncheck1 = one * two\\nprint(check1 // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\na = m * n\\nprint(a // 2)\\n\",\n \"def solve():\\n\\t(n, m) = input().split()\\n\\t(n, m) = (int(n), int(m))\\n\\treturn int(n * m / 2)\\nprint(solve())\\n\",\n \"(a, b) = map(int, input().split())\\nif a * b % 9 != 0:\\n\\tprint(int(a * b / 2))\\nelse:\\n\\tprint(int(a * b // 2))\\n\",\n \"squares = [int(x) for x in input().split()]\\nprint(squares[0] * squares[1] // 2)\\n\",\n \"(base, altura) = map(int, input().split())\\nprint(base * altura // 2)\\n\",\n \"inp = input().split()\\nwidth = int(inp[0])\\nheight = int(inp[1])\\nif width % 2 == 0 or height % 2 == 0:\\n\\tdominoes = int(width * height // 2)\\nelse:\\n\\tdominoes = int((width * height - 1) // 2)\\nprint(dominoes)\\n\",\n \"a = list(map(int, input().split()))\\n(M, N) = (a[0], a[1])\\nprint(M * N // 2)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nsum = 0\\nif n != 1:\\n\\tsum = m * math.floor(n / 2)\\n\\tif n % 2 != 0:\\n\\t\\tsum += math.floor(m / 2)\\nprint(sum)\\n\",\n \"(a, b) = map(int, input().split())\\nsize = a * b\\ndominoes = size // 2\\nprint(dominoes)\\n\",\n \"def TotalDominos(m, n):\\n\\treturn m * n // 2\\nvals = input().split()\\nm = int(vals[0])\\nn = int(vals[1])\\nprint(TotalDominos(m, n))\\n\",\n \"texto = input('')\\nvalores = texto.split(' ')\\nM = int(valores[0])\\nN = int(valores[1])\\np = M * N\\nif p % 2 == 0:\\n\\tc = p // 2\\nelse:\\n\\tc = (p - 1) // 2\\nprint(c)\\n\",\n \"import math\\n(X, Y) = map(int, input().split())\\np_in_x = X\\nrotated_pieces = 0\\nif Y % 2 == 0:\\n\\tp_in_y = int(Y / 2)\\nelse:\\n\\tp_in_y = int(Y / 2)\\n\\trotated_pieces = int(X / 2)\\npieces = p_in_x * p_in_y + rotated_pieces\\nprint(int(pieces))\\n\",\n \"lists = list(map(int, input().split(' ')))\\nz = int(lists[0] * lists[1] / 2)\\nprint(str(z))\\n\",\n \"(r, c) = map(int, input().split())\\nprint(r * c // 2)\\n\",\n \"x = str(input())\\nM = x[:2]\\nN = x[-2:]\\nM = int(M)\\nN = int(N)\\ny = int(M * N / 2)\\nprint(y)\\n\",\n \"a = [int(x) for x in input().split()]\\nM = a[0]\\nN = a[1]\\nprod = M * N\\nremainder = prod % 2\\nif remainder == 0:\\n\\tprint(int(prod / 2))\\nelse:\\n\\tans = prod - remainder\\n\\tprint(int(ans / 2))\\n\",\n \"import math as mt\\nfrom collections import *\\ninf = float('inf')\\n\\ndef ii():\\n\\treturn int(input())\\n\\ndef mii():\\n\\treturn map(int, input().split())\\n\\ndef lii():\\n\\treturn list(map(int, input().split()))\\n\\ndef gmat(n, m):\\n\\treturn [[0] * m for _ in range(n)]\\n\\ndef imat(n):\\n\\treturn [list(mii()) for _ in range(n)]\\n(n, m) = mii()\\nprint(mt.floor(n * m * 0.5))\\n\",\n \"def domino_piling(m, n):\\n\\treturn m * n // 2\\n[m, n] = map(int, input().split())\\nresult = domino_piling(m, n)\\nprint(result)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nif m != 1:\\n\\tif m % 2 == 1:\\n\\t\\tprint(math.floor(m / 2) * n + n // 2)\\n\\telse:\\n\\t\\tprint(math.floor(m / 2) * n)\\nelif n % 2 == 1:\\n\\tprint(math.floor(n / 2) * m + m // 2)\\nelse:\\n\\tprint(math.floor(n / 2) * m)\\n\",\n \"import math\\n(n, m) = map(int, input().split())\\na = math.floor(n * m / 2)\\nprint(a)\\n\",\n \"inStr = input()\\nm = inStr.split()[0]\\nn = inStr.split()[1]\\nm = int(m)\\nn = int(n)\\nprint(m * n // 2)\\n\",\n \"board = input()\\nboard_dim = board.split(' ')\\nM = int(board_dim[0])\\nN = int(board_dim[1])\\nprint(M * N // 2)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\ndom = area // 2\\nprint(dom)\\n\",\n \"g = list(map(int, input().split()))\\nif g[0] < 2 and g[1] < 2:\\n\\tprint('0')\\nelse:\\n\\tprint(int(g[0] * g[1] / 2))\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\na = 2\\nb = n * m\\nx = b / a\\nz = int(x)\\nprint(z)\\n\",\n \"(M, N) = input().split()\\na = int(int(M) * int(N) / 2)\\nprint(a)\\n\",\n \"(M, N) = input().split()\\ns = int(M) * int(N)\\ns //= 2\\nprint(s)\\n\",\n \"n = list(map(int, input().rstrip(' ').split(' ')))\\nsize = n[0] * n[1]\\nprint(size // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nx = a * b / 2\\nprint(int(x))\\n\",\n \"(squares_x, squares_y) = map(int, input().split())\\nsquares_Sum = squares_x * squares_y\\nprint(int(squares_Sum / 2))\\n\",\n \"s = input()\\n(m, n) = [int(i) for i in s.split()]\\nprint(m * n // 2)\\n\",\n \"def main(m, n):\\n\\treturn m * n // 2\\n(m, n) = map(int, input().split(' '))\\nprint(main(m, n))\\n\",\n \"[a, b] = input().split()\\nc = int(a) * int(b)\\nprint(c // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nnum = a * b\\nprint(num // 2)\\n\",\n \"import math\\n(m, n) = [int(m) for m in input().split()]\\nprint(math.floor(m * n / 2))\\n\",\n \"tmp = input().split()\\nS = int(tmp[0]) * int(tmp[1])\\nprint(S // 2)\\n\",\n \"x = input().split()\\nx[0] = int(x[0])\\nx[1] = int(x[1])\\ns = x[0] * x[1]\\nprint(int(s / 2))\\n\",\n \"def main():\\n\\t(m, n) = get_ints()\\n\\tresult = m * n // 2\\n\\tprint(result)\\n\\ndef get_ints():\\n\\treturn (int(x) for x in input().split(' '))\\nmain()\\n\",\n \"str = input()\\nboardSize = [int(s) for s in str.split() if s.isdigit()]\\nsurfArea = boardSize[0] * boardSize[1]\\ntotal = surfArea / 2\\nprint(int(total))\\n\",\n \"board_dimensions = [int(s) for s in input().split(' ')]\\narea = board_dimensions[0] * board_dimensions[1]\\nprint(int(area / 2))\\n\",\n \"import math\\ninp = input()\\ninp = inp.split(' ')\\nboardSize = float(inp[0]) * float(inp[1])\\nans = int(math.floor(boardSize / 2))\\nprint(ans)\\n\",\n \"import math\\narr = list(map(int, input().split()))\\nprint(math.floor(arr[0] * arr[1] / 2))\\n\",\n \"x = input()\\nints = [int(s) for s in x.split() if s.isdigit()]\\nprint(ints[0] * ints[1] // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nd = m * n\\nif d % 2 == 0:\\n\\te = d // 2\\n\\tprint(e)\\nelse:\\n\\to = (d - 1) // 2\\n\\tprint(o)\\n\",\n \"(x, y) = [int(x) for x in input().split()]\\nk = int(x * y / 2)\\nprint(k)\\n\",\n \"from math import floor\\n(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\tprint(int(m / 2) * n)\\nelse:\\n\\tprint(int(m / 2) * n + int(n / 2))\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nS_mn = n * m\\nS_p = 2 * 1\\ncount = int(S_mn / S_p)\\nprint(count)\\n\",\n \"__author__ = 'runekri3'\\n(m, n) = map(int, input().split(' '))\\nres = m // 2 * n\\nif m % 2:\\n\\tres += n // 2\\nprint(res)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m >= 1 and m <= 16 and (n >= 1) and (n <= 16):\\n\\tarea = m * n\\n\\tsize = 2\\n\\tcount = area // size\\nelse:\\n\\tquit()\\nprint(count)\\n\",\n \"(a, b) = map(int, input().split())\\nprint(a * b >> 1)\\n\",\n \"entrada = input().split(' ')\\nm = int(entrada[0])\\nn = int(entrada[1])\\nprint(m * n // 2)\\n\",\n \"(n, k) = map(int, input().split())\\ns = n * k // 2\\nprint(s)\\n\",\n \"(m, n) = map(int, input().strip().split())\\nmul = m * n\\nif mul == 1:\\n\\tprint(0)\\nelif mul % 2 == 0:\\n\\tprint(int(mul / 2))\\nelse:\\n\\tprint(int((mul - 1) / 2))\\n\",\n \"import sys\\nline = sys.stdin\\nline2 = line.readline()\\nline3 = line2.split()\\na = int(line3[0])\\nb = int(line3[1])\\narea = int(a * b)\\noutput = int(area / 2)\\nprint(output)\\n\",\n \"(m, n) = input().strip().split(' ')\\n(m, n) = [int(m), int(n)]\\nans = m * n // 2\\nprint(ans)\\n\",\n \"t = list(map(int, input().split(' ')))\\na = t[0]\\nb = t[1]\\nprint(a * b // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nArea = M * N\\nRes = Area / 2\\nprint(int(Res))\\n\",\n \"(n, m) = input().split()\\n\\ndef domino(n, m):\\n\\tif n % 2 == 0 and m % 2 == 0:\\n\\t\\treturn n * m // 2\\n\\telif n % 2 != 0 and m % 2 == 0:\\n\\t\\treturn m // 2 * n\\n\\telif m % 2 != 0 and n % 2 == 0:\\n\\t\\treturn n // 2 * m\\n\\telif n % 2 != 0 and m % 2 != 0:\\n\\t\\treturn n * m // 2\\nprint(domino(int(n), int(m)))\\n\",\n \"import sys\\nlines = sys.stdin.readlines()\\ninput1 = list(map(int, lines[0].split()))\\n\\ndef size(n, m):\\n\\tprint(int(n * m / 2))\\nsize(input1[0], input1[1])\\n\",\n \"import math\\nv = [int(x) for x in input().split(' ')]\\nm = v[0]\\nn = v[1]\\na = max(m, n)\\nb = min(m, n)\\nc = int(a / 2)\\nd = int(b / 2)\\nif a % 2 == 0:\\n\\te = c * b\\nelse:\\n\\te = d + c * b\\nprint(e)\\n\",\n \"TN = 1\\n\\ndef solution():\\n\\t(m, n) = map(int, input().split())\\n\\t(m, n) = (min(m, n), max(m, n))\\n\\tprint(m * n // 2)\\nwhile TN != 0:\\n\\tsolution()\\n\\tTN -= 1\\n\",\n \"def main():\\n\\t(n, m) = [int(i) for i in input().split()]\\n\\tprint(n * m // 2)\\nmain()\\n\",\n \"import math\\n(n, m) = input().split()\\nm = int(m)\\nn = int(n)\\nm = n * m\\nprint('{}'.format(math.floor(m / 2)))\\n\",\n \"from math import floor\\n[a, b] = map(int, input().split())\\nprint(floor(a * b * (1 / 2)))\\n\",\n \"(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nif x % 2 == 1 and y % 2 == 1:\\n\\tans = int((x * y - 1) / 2)\\nelse:\\n\\tans = int(x * y / 2)\\nprint(ans)\\n\",\n \"n = input().split()\\n(m, n, domino) = (int(n[0]), int(n[1]), 2)\\nprint(m * n // domino)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m % 2 == 1 and n % 2 == 1:\\n\\tresult = int((m * n - 1) / 2)\\nelse:\\n\\tresult = int(m * n / 2)\\nprint(result)\\n\",\n \"import sys\\nimport math as mt\\ninput = sys.stdin.buffer.readline\\nt = 1\\nfor __ in range(t):\\n\\t(m, n) = map(int, input().split())\\n\\tif m % 2 == 0:\\n\\t\\tprint(m // 2 * n)\\n\\telse:\\n\\t\\tprint((m - 1) // 2 * n + n // 2)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\ni = 0\\ns = m * n\\nwhile s >= 2:\\n\\ts -= 2\\n\\ti += 1\\nprint(i)\\n\",\n \"import os\\nimport sys\\nfrom atexit import register\\nfrom io import BytesIO\\ninput = lambda : sys.stdin.readline().rstrip('\\\\r\\\\n')\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef insr():\\n\\ts = input()\\n\\treturn list(s[:len(s) - 1])\\n\\ndef invr():\\n\\treturn map(int, input().split())\\n(m, n) = invr()\\nprint(m // 2 * n + m % 2 * n // 2)\\n\",\n \"[m, n] = [int(i) for i in input().split()]\\np = m * n\\ncount = 0\\nwhile p - 2 >= 0:\\n\\tcount += 1\\n\\tp -= 2\\nprint(count)\\n\",\n \"line = input()\\nline = line.split()\\na = int(line[0])\\nb = int(line[1])\\nif a % 2 == 0 or b % 2 == 0:\\n\\tprint(int(a * b / 2))\\nelif a % 2 != 0 and b % 2 != 0:\\n\\tprint(int((a * b - 1) / 2))\\n\",\n \"(x, y) = map(int, input().split())\\nvolume = x * y\\nmaks = volume // 2\\nprint(maks)\\n\",\n \"(x, y) = map(int, input().split())\\nmul = x * y\\nprint(mul // 2)\\n\",\n \"def solve(mn):\\n\\tmn = mn.split(' ')\\n\\tarr = []\\n\\tfor i in mn:\\n\\t\\tarr.append(i)\\n\\tm = int(arr[0])\\n\\tn = int(arr[1])\\n\\tprint(m * n // 2)\\nmn = str(input())\\nsolve(mn)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\tmnum = m / 2\\n\\tans = mnum * n\\nelif n % 2 == 0:\\n\\tnnum = n / 2\\n\\tans = nnum * m\\nelse:\\n\\tmnum = math.floor(m / 2)\\n\\tnnum = math.floor(n / 2)\\n\\tans = mnum * n + nnum\\nprint(int(ans))\\n\",\n \"s = input()\\nS2 = 2\\ns1 = s.split()\\nl1 = list(s1)\\nl2 = list(map(int, l1))\\nS1 = l2[0] * l2[1]\\nres = S1 // S2\\nprint(res)\\n\",\n \"ip = input().strip().split()\\n(M, N) = (int(ip[0]), int(ip[1]))\\nprint(M * N // 2)\\n\",\n \"(m, n) = input().split()\\nres = int(m) * int(n)\\nresult = res // 2\\nprint(result)\\n\",\n \"import shlex\\na = str(input())\\nl = shlex.split(a)\\nb = int(l[0]) * int(l[1])\\nif b == 1:\\n\\tprint(0)\\nelse:\\n\\tprint(int(b / 2))\\n\",\n \"(n, k) = map(int, input().split())\\nt = n * k // 2\\nprint(t)\\n\",\n \"import math\\n(n, m) = map(int, input().split())\\narea = n * m\\nprint(math.floor(area / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nc = 0\\np = 0\\nwhile p < m * n:\\n\\tp = p + 2\\n\\tc = c + 1\\nif m * n % 2 == 0:\\n\\tprint(c)\\nelse:\\n\\tprint(c - 1)\\n\",\n \"(a, b) = list(map(int, input().split()))\\narea = a * b\\nprint(int(area / 2))\\n\",\n \"import math\\n(x, y) = map(int, input().split(' '))\\nprint(math.floor(x * y / 2))\\n\",\n \"(m, n) = [int(j) for j in input().split()]\\nprint(m * n // 2)\\n\",\n \"(m, n) = input().split()\\n(m, n) = (int(m), int(n))\\nif m % 2 == 0 and n % 2 == 0:\\n\\ts = m // 2 * n\\nelif m % 2 == 1 and n % 2 == 1:\\n\\ts = m // 2 * n\\n\\ts += n // 2\\nelif m % 2 == 1 and n % 2 == 0:\\n\\ts = m // 2 * n\\n\\ts += n // 2\\nelse:\\n\\ta = m\\n\\tm = n\\n\\tn = a\\n\\ts = m // 2 * n\\n\\ts += n // 2\\nprint(s)\\n\",\n \"string = input()\\nstring = string.split(' ')\\nm = int(string[0])\\nn = int(string[1])\\nprint(int(m * n / 2))\\n\",\n \"import math\\na = [int(i) for i in input().split(' ')]\\nn = a[0]\\nm = a[1]\\nprint(math.floor(n * m / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nhe_so = 0\\nso_gach = 0\\nif n % 2 == 0:\\n\\the_so = int(n / 2)\\n\\tso_gach = m * he_so\\nelse:\\n\\the_so = n // 2\\n\\tso_gach_tam_1 = m * he_so\\n\\tso_gach_tam_2 = m // 2\\n\\tso_gach = so_gach_tam_1 + so_gach_tam_2\\nprint(so_gach)\\n\",\n \"(rsk, ksk) = [int(i) for i in input().split()]\\nprint(int(rsk * ksk / 2))\\n\",\n \"(m, n) = input().split()\\narea = int(m) * int(n)\\nif area < 2:\\n\\tprint(0)\\nelif area % 2 == 0:\\n\\tprint(int(area / 2))\\nelif area % 2 == 1:\\n\\tarea -= 1\\n\\tprint(int(area / 2))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nar = M * N\\nif ar < 2:\\n\\tprint(0)\\nelse:\\n\\tprint(int(ar / 2))\\n\",\n \"import math\\nimport sys\\nimport re\\n(m, n) = map(int, input().rstrip().split())\\na = m * n\\nprint(int(a // 2))\\n\",\n \"while True:\\n\\ttry:\\n\\t\\tline = input()\\n\\t\\tline = line.split()\\n\\t\\t(m, n) = [int(n) for n in line]\\n\\t\\tprint(m * n // 2)\\n\\texcept EOFError:\\n\\t\\tbreak\\n\",\n \"(m, n) = [int(j) for j in input().split()]\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"l1 = input().split(' ')\\nprint(int(int(l1[0]) * int(l1[1]) / 2))\\n\",\n \"line = input()\\n(m1, n1) = line.split()\\nm = int(m1)\\nn = int(n1)\\nif m * n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(m * n // 2))\\n\",\n \"import math\\nl = list(map(int, input().split()))\\n(m, n) = (l[0], l[1])\\nprint(math.floor(m * n / 2))\\n\",\n \"def main():\\n\\t(n, m) = map(int, input().split(' '))\\n\\ttemp = n * m\\n\\tprint(temp // 2)\\nmain()\\n\",\n \"try:\\n\\tmn = input()\\n\\tmn = mn.split()\\n\\tprint(int(mn[0]) * int(mn[1]) // 2)\\nexcept Exception as e:\\n\\tprint(e)\\n\",\n \"(x, y) = input().split()\\nhorizPerRow = int(int(x) / 2)\\ntotalHoriz = int(int(y) * horizPerRow)\\ntotalVert = 0\\nif int(x) % 2 == 1:\\n\\ttotalVert = int(int(y) / 2)\\ntotal = totalHoriz + totalVert\\nprint(int(total))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(m * n // 2)\\nelse:\\n\\tprint(max(m * (n // 2) + m // 2, n * (m // 2) + n // 2))\\n\",\n \"a = list(map(int, input().split()))\\nn = a[0]\\nm = a[1]\\nboard = m * n\\nsol = board / 2\\nsol = int(sol)\\nprint(sol)\\n\",\n \"import math as mt\\n(m, n) = [int(x) for x in input().split(' ')]\\nprod = m * n\\noutput = mt.floor(prod / 2)\\nprint(output)\\n\",\n \"import math\\n(n, m) = map(int, input().split())\\nmax_dominos = m * n / 2\\nprint(math.floor(max_dominos))\\n\",\n \"(m, n) = input().split()\\n(m, n) = (int(m), int(n))\\nk = 0\\nif m % 2 != 0 and n % 2 != 0:\\n\\tk = m - 1\\n\\tprint(int(k * n / 2 + (n - 1) / 2))\\nelse:\\n\\tprint(int(m * n / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nb = int(m * n)\\nd = 2\\nmax = int(b / d)\\nprint(round(max))\\n\",\n \"lst = [int(x) for x in input().split()]\\n(m, n) = lst\\n\\ndef func(m, n):\\n\\tif n % 2 == 0 or m % 2 == 0:\\n\\t\\tres = m * n / 2\\n\\telse:\\n\\t\\tres = (m * n - 1) / 2\\n\\treturn int(res)\\nprint(func(m, n))\\n\",\n \"import sys\\n(n, m) = map(int, input().split(' '))\\nif n == 1 and m % 2 == 0:\\n\\ty = m // 2\\n\\tx = int(n // 2 * m)\\n\\tpass\\nelse:\\n\\tif n % 2 == 0:\\n\\t\\tk = 0\\n\\t\\tpass\\n\\telse:\\n\\t\\tk = 1\\n\\tx = int(n // 2 * m)\\n\\ty = int(m // 2 * k)\\nans = int(x + y)\\nprint(ans)\\n\",\n \"m = list(map(int, input().split()))\\ntotal_area = m[0] * m[1]\\nprint(total_area // 2)\\n\",\n \"from sys import stdin\\n\\ndef main():\\n\\t(n, k) = map(int, stdin.readline().rstrip().split())\\n\\tprint(n * k // 2)\\nmain()\\n\",\n \"inp = input().split()\\nm = int(inp[0])\\nn = int(inp[1])\\nres = m * n // 2\\nprint(res)\\n\",\n \"a = input()\\nfor i in range(0, len(a)):\\n\\twhile a[i] == ' ':\\n\\t\\tfirst = int(a[0:i])\\n\\t\\tsecond = int(a[i + 1:])\\n\\t\\tbreak\\ntotal = 0\\nif first >= 2 and second >= 1:\\n\\tif first % 2 == 0:\\n\\t\\ttotal = first / 2 * second\\n\\telse:\\n\\t\\ttotal = (first - 1) / 2 * second + second / 2 * 1\\nif first == 1:\\n\\ttotal = second / 2 * 1\\nprint(int(total))\\n\",\n \"(M, N) = map(int, input().split())\\na = 2 * 1\\nresult = M * N // a\\nprint(result)\\n\",\n \"l = [int(i) for i in input().split()]\\nn = l[0]\\nm = l[1]\\nprint(n * m // 2)\\n\",\n \"import math\\n(n, m) = map(float, input().split())\\nsBoard = n * m\\nnumDomino = math.floor(sBoard / 2)\\nprint(numDomino)\\n\",\n \"import math\\n(x, y) = input().split()\\nm = int(x)\\nn = int(y)\\no = 0\\nif m * n % 2 == 0:\\n\\to = math.floor(m * n / 2)\\nelif m * n % 2 != 0:\\n\\to = math.floor((m * n - 1) / 2)\\nprint(o)\\n\",\n \"try:\\n\\tl = [int(x) for x in input().split()]\\n\\tprint(l[0] * l[1] // 2)\\nexcept:\\n\\tpass\\n\",\n \"(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nprint(x * y // 2)\\n\",\n \"inputs = input()\\ninputs = inputs.split()\\ns = int(inputs[0]) * int(inputs[1])\\nprint(s // 2)\\n\",\n \"import math\\nno = input()\\n(m, n) = no.split()\\nm = int(m)\\nn = int(n)\\narea = m * n\\nans = area / 2\\nprint(math.floor(ans))\\n\",\n \"ch = input()\\nL = ch.strip().split(' ')\\nM = int(L[0])\\nN = int(L[1])\\nprint(int(N * M / 2))\\n\",\n \"(m, n) = map(int, input().split(' '))\\narr = []\\nfor i in range(m):\\n\\tnew = []\\n\\tfor j in range(n):\\n\\t\\tnew.append(0)\\n\\tarr.append(new)\\nplace_holder = (1, 1)\\nfor i in range(len(arr)):\\n\\tfor j in range(0, len(arr[0]) - 1, 2):\\n\\t\\t(arr[i][j], arr[i][j + 1]) = place_holder\\nfor j in range(len(arr[0])):\\n\\tfor i in range(0, len(arr) - 1, 2):\\n\\t\\tif arr[i][j] == 1:\\n\\t\\t\\tcontinue\\n\\t\\telse:\\n\\t\\t\\t(arr[i][j], arr[i + 1][j]) = place_holder\\ncount = 0\\nfor i in range(len(arr)):\\n\\tfor j in range(len(arr[0])):\\n\\t\\tif arr[i][j] == 1:\\n\\t\\t\\tcount += 1\\nprint(round(count / 2))\\n\",\n \"lst = input().strip().split(' ')\\nn = int(lst[0])\\nm = int(lst[1])\\nx = n * m\\nif x % 2 == 0:\\n\\tz = x / 2\\nelse:\\n\\tz = (x - 1) / 2\\nprint(int(z))\\n\",\n \"import queue\\n__read_tokens = queue.Queue()\\n\\ndef next_string():\\n\\twhile __read_tokens.empty():\\n\\t\\tfor i in input().split():\\n\\t\\t\\t__read_tokens.put(i)\\n\\treturn __read_tokens.get()\\n\\ndef next_int():\\n\\treturn int(next_string())\\n\\ndef next_float():\\n\\treturn float(next_string())\\n\\ndef next_line():\\n\\tif not __read_tokens.empty():\\n\\t\\traise Exception('Unclean token cache')\\n\\treturn input()\\nn = next_int()\\nm = next_int()\\nx = (n * m - n * m % 2) // 2\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\ntotal = m * n\\ntotal1 = total // 2\\nprint(total1)\\n\",\n \"def solution(m, n):\\n\\tprint(m * n // 2)\\nli = [int(x) for x in input().split()]\\nm = li[0]\\nn = li[-1]\\nsolution(m, n)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nh = 0\\nh = b // 2 * a\\nif b % 2 == 1 or b == 1:\\n\\th += a // 2\\nprint(h)\\n\",\n \"k = input()\\nt = k.split(' ')\\n(n, m) = (int(t[0]), int(t[1]))\\nif n % 2 == 0 or m % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(((m - 1) * (n - 1) + m + n - 2) / 2))\\n\",\n \"(m, n) = input().split()\\nwhile True:\\n\\ttry:\\n\\t\\tm = int(m)\\n\\t\\tn = int(n)\\n\\t\\tif n <= 16 and m <= n:\\n\\t\\t\\tbreak\\n\\t\\telse:\\n\\t\\t\\tprint()\\n\\t\\t\\t(m, n) = input().split()\\n\\texcept ValueError:\\n\\t\\tprint: ()\\n\\t\\t(m, n) = input().split()\\nmax = m * n / 2\\nimport math\\nrddownmax = math.floor(max)\\nprint(rddownmax)\\n\",\n \"(n, m) = map(int, input().split())\\nx = m * n\\nif n < 1:\\n\\tprint(0)\\nelif n == 1:\\n\\tif m <= 1:\\n\\t\\tprint(0)\\n\\telse:\\n\\t\\tprint(int(x / 2))\\nelif m < 1:\\n\\tprint(0)\\nelse:\\n\\tprint(int(x / 2))\\n\",\n \"(x, y) = map(int, input().split())\\nif x * y % 2 == 0:\\n\\tprint(int(x * y / 2))\\nelse:\\n\\tprint(int((x * y - 1) / 2))\\n\",\n \"(M, N) = map(int, input().split())\\n(m, n) = (max(M, N), min(M, N))\\nif m % 2 == 1 and n % 2 == 1:\\n\\tnumber = (m * n - 1) / 2\\nelse:\\n\\tnumber = m * n / 2\\nprint(int(number))\\n\",\n \"def sol(m, n):\\n\\tres = m * n // 2\\n\\treturn res\\n(m, n) = map(int, input().split(' '))\\nprint(sol(m, n))\\n\",\n \"domino_area = 2\\n\\ndef domino():\\n\\tnums = [int(elem) for elem in input().split()]\\n\\tprint(nums[0] * nums[1] // domino_area)\\ndomino()\\n\",\n \"numbers = input()\\ns = numbers.split(' ')\\na = int(s[0])\\nb = int(s[1])\\nprint(int((a * b - a * b % 2) / 2))\\n\",\n \"(n, m) = map(int, input().split())\\np = m / 2\\nq = n / 1\\nprint(int(p * q))\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nA = M * N\\nK = A // 2\\nprint(K)\\n\",\n \"a = input().split()\\n(m, n) = a\\nm = int(m)\\nn = int(n)\\ndominos = m * n // 2\\nprint(dominos)\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n(short_side, long_side) = input().split()\\nshort_side = int(short_side)\\nlong_side = int(long_side)\\nif short_side < 2:\\n\\tprint(long_side // 2)\\n\\texit()\\nnum_parallels = long_side\\nnum_rows = short_side // 2\\nextra_blocks = 0\\nif short_side % 2 != 0:\\n\\textra_blocks = long_side // 2\\ntotal_blocks = num_parallels * num_rows + extra_blocks\\nprint(total_blocks)\\n\",\n \"M_and_N = list(map(int, input().split()))\\nS = M_and_N[0] * M_and_N[1]\\nnum = S // 2\\nprint(num)\\n\",\n \"def domino(m, n):\\n\\tresult = 0\\n\\tresult = m * n\\n\\tif result > 1:\\n\\t\\tif result % 2 == 0:\\n\\t\\t\\tresult //= 2\\n\\t\\t\\tprint(result)\\n\\t\\telif result % 2 != 0:\\n\\t\\t\\tresult = (result - 1) // 2\\n\\t\\t\\tprint(result)\\n\\telse:\\n\\t\\tprint('0')\\n(m, n) = (a for a in input().split(' '))\\nm = int(m)\\nn = int(n)\\ndomino(m, n)\\n\",\n \"def board(input):\\n\\tm = int(input.split(' ')[0])\\n\\tn = int(input.split(' ')[1])\\n\\tif m >= 1 and m <= 16 and (n >= 1) and (n <= 16):\\n\\t\\tprint(int(m * n / 2))\\n\\telse:\\n\\t\\treturn\\nboard(input())\\n\",\n \"i = input().split()\\nm = int(i[0])\\nn = int(i[1])\\nprint(m * n // 2)\\n\",\n \"temp = input()\\ntemp = temp.split()\\nm = int(temp[0])\\nn = int(temp[1])\\nresult = int(m * n / 2)\\nprint(str(result))\\n\",\n \"from math import ceil\\n(m, n) = map(int, input().split())\\nprint(ceil(m * n) // 2)\\n\",\n \"from math import floor\\n(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nz = x * y\\nv = floor(z / 2)\\nprint(v)\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\ne = []\\nfor i in list_we_use:\\n\\te.append(int(i))\\nprint(e[0] * e[1] // 2)\\n\",\n \"(v, t) = [int(x) for x in input().split()]\\nif v * t % 2 == 0:\\n\\tprint(int(v * t / 2))\\nelse:\\n\\tprint(int((v * t - 1) / 2))\\n\",\n \"from sys import stdin\\n\\ndef main():\\n\\ta = stdin.readline().strip()\\n\\twhile a != '':\\n\\t\\t(b, c) = a.split()\\n\\t\\t(b, c) = (int(b), int(c))\\n\\t\\td = b * c\\n\\t\\tcont = 0\\n\\t\\twhile d > 1:\\n\\t\\t\\tcont += 1\\n\\t\\t\\td = d - 2\\n\\t\\tprint(cont)\\n\\t\\ta = stdin.readline().strip()\\nmain()\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\na = max(n, m)\\nb = min(m, n)\\nsums = a * (b // 2)\\nif b % 2 != 0:\\n\\tsums = sums + a // 2\\nprint(sums)\\n\",\n \"(a, b) = map(int, input().split())\\nc = int(a * b)\\nd = 2\\nmaximum1 = int(c / d)\\nprint(round(maximum1))\\n\",\n \"text = input()\\nx = text.split(' ')\\nresult = int(x[0]) * int(x[1]) / 2\\nprint(int(result))\\n\",\n \"(a, b) = list(map(int, input().strip().split(' ')))\\nm = max(a, b)\\nn = min(a, b)\\nres = n // 2\\nres1 = m // 2\\nif n % 2 != 0 and m % 2 == 0:\\n\\tans = res * m + res1\\nelif n % 2 != 0 and m % 2 != 0:\\n\\tans = res * m + res1\\nelse:\\n\\tans = res * m\\nprint(ans)\\n\",\n \"(m, n) = input().split()\\nn = int(n)\\nm = int(m)\\nz = m * n / 2\\nz = int(z)\\nprint(z)\\n\",\n \"import math\\npieces = input().split()\\nm = max(int(pieces[0]), int(pieces[1]))\\nn = min(int(pieces[0]), int(pieces[1]))\\nif m % 2 == 0:\\n\\tx = int(m / 2)\\n\\ty = n\\n\\ts = x * y\\n\\tprint(s)\\nelif m == 1:\\n\\tprint(0)\\nelse:\\n\\tx = math.floor(m / 2)\\n\\ty = math.floor(n / 2)\\n\\ts = x * n + y\\n\\tprint(s)\\n\",\n \"k = list(map(int, input().strip().split(' ')))\\nprint(k[1] * k[0] // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nif a % 2 == 0 or b % 2 == 0:\\n\\ts = a * b / 2\\nelse:\\n\\ts = (a * b - 1) / 2\\ns = int(s)\\nprint(s)\\n\",\n \"def rex():\\n\\ts = input().split(' ')\\n\\tm = int(s[0])\\n\\tn = int(s[1])\\n\\tif m % 2 == 0:\\n\\t\\treturn m * n\\n\\tif n % 2 == 0:\\n\\t\\treturn m * n\\n\\treturn m * n - 1\\n\\treturn max(val1, val2)\\nprint(int(rex() / 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ny = m * n // 2\\nprint(y)\\n\",\n \"def test_case(m, n):\\n\\tnum_tiles = m * n\\n\\tresult = num_tiles // 2\\n\\tprint(result)\\n(m, n) = [int(x) for x in input().split(' ')]\\ntest_case(m, n)\\n\",\n \"(m, n) = map(int, input().split())\\nprint(m * n >> 1)\\n\",\n \"x = input()\\nparts = x.split(' ')\\nx = int(parts[0])\\ny = int(parts[1])\\npieces = 0\\nif y >= 2:\\n\\twhile not y <= 1:\\n\\t\\twhile not x <= 0:\\n\\t\\t\\tx -= 1\\n\\t\\t\\tpieces += 1\\n\\t\\ty -= 2\\n\\t\\tx = int(parts[0])\\nelif x >= 2:\\n\\twhile not x <= 1:\\n\\t\\tx -= 2\\n\\t\\tpieces += 1\\nx = int(parts[0])\\nif y == 1:\\n\\twhile not x <= 1:\\n\\t\\tx -= 2\\n\\t\\tpieces += 1\\nprint(pieces)\\n\",\n \"inp = list(map(int, input().split()))\\nn = inp[0]\\nk = inp[1]\\nprint(n * k // 2)\\n\",\n \"import math\\nm = input()\\nm_n = list(map(int, (x for x in m.split() if x.isdigit())))\\nbrd_sz = m_n[0] * m_n[1]\\nnum = math.floor(brd_sz / 2)\\nprint(num)\\n\",\n \"line = input()\\n(m, n) = [int(i) for i in line.split()]\\nprint(m * n // 2)\\n\",\n \"(n, m) = list(map(int, input().strip().split()))\\nboard_size = n * m\\ncheck = 0\\nif board_size % 2 == 0:\\n\\tcheck = board_size * 0.5\\nelse:\\n\\tcheck = board_size * 0.5 - 0.5\\nprint(int(check))\\n\",\n \"(a, b) = input().split()\\narea = int(a) * int(b)\\nnum = area // 2\\nprint(num)\\n\",\n \"factors = input()\\nfactor_list = factors.split()\\narea = int(factor_list[0]) * int(factor_list[1])\\nnumber_dominoes = area // 2\\nprint(number_dominoes)\\n\",\n \"import math\\n(m, n) = [int(x) for x in input().split()]\\nif not m % 2:\\n\\tans = m / 2 * n\\nelse:\\n\\tans = (m - 1) / 2 * n + math.floor(n / 2)\\nprint(int(ans))\\n\",\n \"mn = input().split()\\narea = int(mn[0]) * int(mn[1])\\nprint(area // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nmax_count = 0\\nmax_count = M * N // 2\\nprint(max_count)\\n\",\n \"(a, b) = map(int, input().split())\\nc = 0\\nif a % 2 == 0:\\n\\tc = b * (a // 2)\\nelse:\\n\\tc = b * (a // 2) + b // 2\\nprint(c)\\n\",\n \"a = input()\\n(m, n) = a.split()\\nm = int(m)\\nn = int(n)\\nval = 0\\nif m * n % 2 == 0:\\n\\tval = m * n / 2\\nelse:\\n\\tval = (m * n - 1) / 2\\nprint(int(val))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ntemp = m\\nwhile True:\\n\\tif temp % 2 == 0:\\n\\t\\tbreak\\n\\ttemp -= 1\\nrows_left = m - temp\\ndom = temp // 2 * n\\nif rows_left > 0:\\n\\tif n % 2 == 0:\\n\\t\\tdom += n // 2\\n\\telse:\\n\\t\\ttemp1 = n\\n\\t\\twhile True:\\n\\t\\t\\tif temp1 % 2 == 0:\\n\\t\\t\\t\\tbreak\\n\\t\\t\\ttemp1 -= 1\\n\\t\\tdom += temp1 // 2\\nprint(dom)\\n\",\n \"(M, N) = map(int, input().strip().split())\\nif M >= 1 and M <= 16 and (N >= 1) and (N <= 16):\\n\\tdominoPieces = int(M / 2) * N + M % 2 * int(N / 2)\\n\\tprint(dominoPieces)\\nelse:\\n\\tquit()\\n\",\n \"(a, b) = list(map(int, input().strip().split(' ')))\\nprint(a * b // 2)\\n\",\n \"table = [int(w) for w in input().split()]\\nprint(table[0] * table[1] // 2)\\n\",\n \"constraints = list(map(int, input().split()))\\nans = int(constraints[1] * constraints[0] * 0.5)\\nprint(ans)\\n\",\n \"def main():\\n\\t(m, n) = [int(x) for x in input().split()]\\n\\tif n == 1 and m == 1:\\n\\t\\tprint(0)\\n\\t\\treturn\\n\\tif n % 2 == 0:\\n\\t\\tprint(n // 2 * m)\\n\\t\\treturn\\n\\tif m % 2 == 0:\\n\\t\\tprint(m // 2 * n)\\n\\t\\treturn\\n\\tif m < n:\\n\\t\\tt = m\\n\\t\\tm = n\\n\\t\\tn = t\\n\\tprint(m // 2 * n + n // 2)\\n\\treturn\\nmain()\\n\",\n \"inp = [x for x in input().strip().split(' ')]\\n(m, n) = (int(inp[0]), int(inp[1]))\\nmult = m * n\\nprint((mult - 1) // 2 if mult % 2 == 1 else mult // 2)\\n\",\n \"import math\\n[m, n] = input().split()\\nM = int(m)\\nN = int(n)\\nprint(math.floor(M * N / 2))\\n\",\n \"(m, n) = list(map(int, input().split()))\\nif m >= 1 and n >= m and (n <= 16):\\n\\tk = m * n\\n\\tprint(k // 2)\\n\",\n \"mn1 = str(input())\\nmn = mn1.split()\\nm = int(mn[0])\\nn = int(mn[1])\\na = m * n\\nprint(a // 2)\\n\",\n \"M = list(map(lambda x: int(x), input().split()))\\nprint(M[0] * M[1] // 2)\\n\",\n \"(M, N) = input().split()\\nN = int(N)\\nM = int(M)\\nsquare = N * M\\nif 1 <= M <= N <= 16:\\n\\tprint(square // 2)\\n\",\n \"L = input().split(' ')\\nm = int(L[0])\\nn = int(L[1])\\nif n % 2 == 0:\\n\\tprint(m * (n // 2))\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"piece = input().split()\\nm = int(piece[0])\\nn = int(piece[1])\\nanswer = m * n // 2\\nprint(answer)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nresult = int(a / 2)\\nprint(result)\\n\",\n \"mn = list(map(int, input().rstrip().split()))\\nm = mn[0]\\nn = mn[1]\\ncount = m // 2\\nif m % 2 == 0:\\n\\tprint(count * n)\\nelse:\\n\\tprint(count * n + n // 2)\\n\",\n \"(n, m) = [int(value) for value in input().split(' ')]\\nprint(int(n * m // 2))\\n\",\n \"(a, b) = input().split(' ')\\na = int(a)\\nb = int(b)\\nx = a * b\\ny = x // 2\\nprint(y)\\n\",\n \"x = input()\\nx = x.split(' ')\\nM = int(x[0])\\nN = int(x[1])\\nprint(int(M * N / 2))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\np = m // 2\\nq = n // 2\\nif m % 2 == 0:\\n\\tprint(p * n)\\nelif m == 1:\\n\\tprint(q)\\nelif n == 1:\\n\\tprint(p)\\nelse:\\n\\tprint(p * n + q)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nba = m * n\\nif 1 <= m <= 16 and 1 <= n <= 16:\\n\\tif ba % 2 == 0:\\n\\t\\tprint(int(ba / 2))\\n\\telif (ba - 1) % 2 == 0:\\n\\t\\tprint(int((ba - 1) / 2))\\n\",\n \"(m, n) = map(int, input().strip().split())\\nmul = m * n\\nprint(mul // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nb = False\\nif m % 2 != 0:\\n\\tb = True\\nprint((n * int(m / 2) + int(n / 2) * b, int(n / 2))[m < 2])\\n\",\n \"a = input()\\nb = a.split()\\ns = int(b[0]) * int(b[1])\\nn = s // 2\\nprint(n)\\n\",\n \"l = list(map(int, input().split()))\\nd = int(l[0] * l[1] / 2)\\nprint(d)\\n\",\n \"(q, w) = list(map(int, input().split()))\\nprint(q * w // 2)\\n\",\n \"s = input()\\nline = list(s.split())\\ns1 = int(line[0])\\ns2 = int(line[1])\\nprint(s1 * s2 // 2)\\n\",\n \"(n, m) = (int(x) for x in input().split())\\na = n * m\\nprint(a // 2)\\n\",\n \"def main():\\n\\t(m, n) = input().split()\\n\\tm = int(m)\\n\\tn = int(n)\\n\\tthe_area = m * n\\n\\tprint(int(the_area / 2))\\nmain()\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nnum = m * n / 2\\nprint(int(num))\\n\",\n \"import sys\\n(length, breadth) = map(int, sys.stdin.readline().split())\\nnumbers = 0\\nif length >= 2:\\n\\tnumbers = breadth * (length // 2)\\n\\tif length % 2 == 1:\\n\\t\\tnumbers = numbers + breadth // 2\\nelif breadth >= 2:\\n\\tnumbers = length * (breadth // 2)\\n\\tif breadth % 2 == 1:\\n\\t\\tnumbers = numbers + length // 2\\nprint(numbers)\\n\",\n \"(l, b) = list(map(int, input().split()))\\na = l * b\\ndomino = a // 2\\nprint(domino)\\n\",\n \"r = input()\\nni = r.split()\\nm = int(ni[0])\\nn = int(ni[1])\\nx = int(m * n / (2 * 1))\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0 or n % 2 == 0:\\n\\tans = m * n / 2\\nelse:\\n\\tans = (m * n - 1) / 2\\nprint(int(ans))\\n\",\n \"n_m = input()\\nlist = n_m.split()\\nn = int(list[0])\\nm = int(list[1])\\nprint(int(n * m / 2))\\n\",\n \"from math import floor\\nl = input().split(' ')\\nl = [int(i) for i in l]\\na = l[0] * l[1]\\nprint(floor(a / 2))\\n\",\n \"L = 2\\n(M, N) = map(int, input().split())\\nluas = M * N\\nprint(luas // L)\\n\",\n \"(M, N) = map(int, input().split())\\nresult = M * N // 2\\nprint(result)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nareaofboard = m * n\\nreminder = areaofboard % 2\\nif reminder == 1:\\n\\tprint(int((areaofboard - 1) / 2))\\nelse:\\n\\tprint(int(areaofboard / 2))\\n\",\n \"(m, n) = [int(c) for c in input().split()]\\nsquare = 2\\ncount = m * n // square\\nprint(count)\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\nprint(a * b // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nk = m * n\\nl = k // 2\\nprint(l)\\n\",\n \"data = input()\\ndataList = data.split(' ')\\nm = int(dataList[0])\\nn = int(dataList[1])\\nnumber = m * n\\nanswer = m * n // 2\\nif number % 2 > 0:\\n\\tanswer = (number - 1) // 2\\nprint(answer)\\n\",\n \"from math import floor\\nar = input()\\nmn = list(map(int, ar.split(' ')))\\nprint(int(floor(mn[0] * mn[1] / 2)))\\n\",\n \"[M, N] = [int(i) for i in input().split()]\\nt = 0\\nt = M * N // 2\\nprint(t)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m > 0 and n > 0:\\n\\tt = m * n // 2\\nprint(t)\\n\",\n \"m = input().split()\\na = int(m[0])\\nb = int(m[1])\\nprint(int(a * b / 2))\\n\",\n \"def count_rectagular_square(m, n):\\n\\treturn m * n\\n\\ndef count_maximum_dominoes(m, n):\\n\\trec_square = count_rectagular_square(m, n)\\n\\tnum = rec_square / 2\\n\\treturn int(num)\\ntry_time = input().strip().split(' ')\\ntry_time = [int(i) for i in try_time]\\nresult = count_maximum_dominoes(try_time[0], try_time[1])\\nprint(result)\\n\",\n \"(n, k) = map(int, input().split())\\nyo = n * k\\nct = 0\\nwhile yo >= 2:\\n\\tct += 1\\n\\tyo = yo - 2\\nprint(ct)\\n\",\n \"(a, b) = map(int, input().split())\\nd = 0\\nif a % 2 == 0 or b % 2 == 0:\\n\\td = a * b / 2\\nelse:\\n\\td = a * b // 2\\nprint(round(d))\\n\",\n \"from sys import stdin, stdout\\nimport math, sys\\nfrom itertools import permutations, combinations\\nfrom collections import defaultdict, deque, OrderedDict\\nfrom os import path\\nimport bisect as bi\\nimport heapq\\n\\ndef yes():\\n\\tprint('YES')\\n\\ndef no():\\n\\tprint('NO')\\nif path.exists('input.txt'):\\n\\tsys.stdin = open('input.txt', 'r')\\n\\tsys.stdout = open('output.txt', 'w')\\n\\n\\tdef I():\\n\\t\\treturn int(input())\\n\\n\\tdef In():\\n\\t\\treturn map(int, input().split())\\nelse:\\n\\n\\tdef I():\\n\\t\\treturn int(stdin.readline())\\n\\n\\tdef In():\\n\\t\\treturn map(int, stdin.readline().split())\\n\\ndef main():\\n\\ttry:\\n\\t\\t(n, m) = In()\\n\\t\\tt = n * m // 2\\n\\t\\tprint(t)\\n\\texcept:\\n\\t\\tpass\\nM = 998244353\\nP = 1000000007\\nfor _ in range(1):\\n\\tmain()\\n\",\n \"size = input().split()\\nM = int(size[0])\\nN = int(size[1])\\nprint(M * N // 2)\\n\",\n \"def ras(m, n):\\n\\ta = 1\\n\\tb = 2\\n\\tif m % 2 == 0 and n % 2 == 0:\\n\\t\\tx = m * n / 2\\n\\t\\treturn int(x)\\n\\tif m % 2 != 0 and n % 2 != 0:\\n\\t\\tx = n // 2 * (m / 1) + m // 2\\n\\t\\treturn int(x)\\n\\tif m % 2 != 0 and n % 2 == 0:\\n\\t\\tx = n / 2 * m\\n\\t\\treturn int(x)\\n\\tif m % 2 == 0 and n % 2 != 0:\\n\\t\\tx = m / 2 * n\\n\\t\\treturn int(x)\\n(m, n) = map(int, input().split())\\nr = ras(m, n)\\nprint(r)\\n\",\n \"x = list(map(int, input().split()))\\na = x[0]\\nb = x[1]\\nans = 0\\nif a % 2 == 0:\\n\\tans = a * b // 2\\nelif b % 2 == 0:\\n\\tans = a * b // 2\\nelse:\\n\\tans = (a * b - 1) // 2\\nprint(ans)\\n\",\n \"(M, N) = [int(a) for a in input().split()]\\nprint(M * N // 2)\\n\",\n \"x = [int(y) for y in input().split()]\\nprint(x[0] * x[1] // 2)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nsolution = a / 2\\nsolution = int(solution)\\nprint(solution)\\n\",\n \"def domino(n, m):\\n\\tdomino = 0\\n\\tfor i in range(n):\\n\\t\\tfor j in range(m):\\n\\t\\t\\tdomino += 1\\n\\tprint(domino // 2)\\nn = input()\\nn = n.split()\\n(n, m) = (int(n[0]), int(n[1]))\\ndomino(n, m)\\n\",\n \"from operator import mul\\nprint(int(mul(*map(int, input().split())) / 2))\\n\",\n \"(a, b) = map(int, input().split())\\nif 1 <= a <= b <= 16:\\n\\tc = a * b // 2\\n\\tprint(c)\\n\",\n \"from sys import stdin\\nboard = stdin.readline().split()\\nboard = list(map(int, board))\\nprint(board[0] * board[1] // 2)\\n\",\n \"m_n = list(map(int, input().split()))\\nmxn = m_n[0] * m_n[1]\\nif mxn % 2 == 0:\\n\\tprint(int(mxn / 2))\\nelse:\\n\\tprint(int((mxn - 1) / 2))\\n\",\n \"import sys\\nimport math\\nimport os\\nimport itertools\\nimport string\\nimport heapq\\nimport _collections\\nfrom collections import Counter\\nfrom collections import defaultdict\\nfrom functools import lru_cache\\nimport bisect\\nimport re\\nimport queue\\nfrom decimal import *\\n\\nclass Scanner:\\n\\n\\t@staticmethod\\n\\tdef int():\\n\\t\\treturn int(sys.stdin.readline().rstrip())\\n\\n\\t@staticmethod\\n\\tdef string():\\n\\t\\treturn sys.stdin.readline().rstrip()\\n\\n\\t@staticmethod\\n\\tdef map_int():\\n\\t\\treturn [int(x) for x in Scanner.string().split()]\\n\\n\\t@staticmethod\\n\\tdef string_list(n):\\n\\t\\treturn [input() for i in range(n)]\\n\\n\\t@staticmethod\\n\\tdef int_list_list(n):\\n\\t\\treturn [Scanner.map_int() for i in range(n)]\\n\\n\\t@staticmethod\\n\\tdef int_cols_list(n):\\n\\t\\treturn [int(input()) for i in range(n)]\\n\\nclass Math:\\n\\n\\t@staticmethod\\n\\tdef gcd(a, b):\\n\\t\\tif b == 0:\\n\\t\\t\\treturn a\\n\\t\\treturn Math.gcd(b, a % b)\\n\\n\\t@staticmethod\\n\\tdef lcm(a, b):\\n\\t\\treturn a * b // Math.gcd(a, b)\\n\\n\\t@staticmethod\\n\\tdef divisor(n):\\n\\t\\tres = []\\n\\t\\ti = 1\\n\\t\\tfor i in range(1, int(n ** 0.5) + 1):\\n\\t\\t\\tif n % i == 0:\\n\\t\\t\\t\\tres.append(i)\\n\\t\\t\\t\\tif i != n // i:\\n\\t\\t\\t\\t\\tres.append(n // i)\\n\\t\\treturn res\\n\\n\\t@staticmethod\\n\\tdef round_up(a, b):\\n\\t\\treturn -(-a // b)\\n\\n\\t@staticmethod\\n\\tdef is_prime(n):\\n\\t\\tif n < 2:\\n\\t\\t\\treturn False\\n\\t\\tif n == 2:\\n\\t\\t\\treturn True\\n\\t\\tif n % 2 == 0:\\n\\t\\t\\treturn False\\n\\t\\td = int(n ** 0.5) + 1\\n\\t\\tfor i in range(3, d + 1, 2):\\n\\t\\t\\tif n % i == 0:\\n\\t\\t\\t\\treturn False\\n\\t\\treturn True\\n\\ndef pop_count(x):\\n\\tx = x - (x >> 1 & 6148914691236517205)\\n\\tx = (x & 3689348814741910323) + (x >> 2 & 3689348814741910323)\\n\\tx = x + (x >> 4) & 1085102592571150095\\n\\tx = x + (x >> 8)\\n\\tx = x + (x >> 16)\\n\\tx = x + (x >> 32)\\n\\treturn x & 127\\nMOD = int(1000000000.0) + 7\\nINF = int(1000000000000000.0)\\n\\ndef solve():\\n\\t(M, N) = Scanner.map_int()\\n\\tprint(M * N // 2)\\n\\ndef main():\\n\\tsolve()\\nmain()\\n\",\n \"a = input().split()\\nn = int(a[0])\\nk = int(a[1])\\nc = k * n // 2\\nprint(c)\\n\",\n \"import math\\n(n, m) = [int(i) for i in input().split()]\\nif 0 <= m * n <= 16 ** 16:\\n\\tprint(math.floor(m * n / 2))\\n\",\n \"x = input()\\n(m, n) = x.split(' ')\\ny = int(m) * int(n)\\nprint(y // 2)\\n\",\n \"x = [int(n) for n in input().split(' ')]\\nnum = x[0] * x[1]\\nprint(int(num / 2))\\n\",\n \"__author__ = 'myduomilia'\\nimport math\\n(a, b) = list(map(int, input().split()))\\nprint(math.floor(a * b * 0.5))\\n\",\n \"k = input()\\ne = k.split(' ')\\nj = []\\nfor i in e:\\n\\tj.append(int(i))\\nm = j[0] * j[1]\\nprint(m // 2)\\n\",\n \"__author__ = 'acer1'\\nshuru = input()\\npieces = shuru.split()\\nchang = int(pieces[0])\\nkuan = int(pieces[1])\\nif chang // 2 != chang // 2 and kuan // 2 != kuan / 2:\\n\\tjieguo = (chang * kuan + 1) / 2\\nelse:\\n\\tjieguo = chang * kuan / 2\\nprint(int(jieguo))\\n\",\n \"import re\\nl = input()\\ns = re.split('\\\\\\\\s+', l)\\nm = int(s[0])\\nn = int(s[1])\\na = m * n\\nsum = a // 2\\nprint(sum)\\n\",\n \"w = list(map(int, input().split()))\\na = w[0]\\nb = w[1]\\nc = a * b\\nif c % 2 > 0:\\n\\tc = c - 1\\nprint(int(c / 2))\\n\",\n \"x = input()\\nz = x.split()\\ntable = int(z[0]) * int(z[1])\\nresult = int(table / 2)\\nprint(result)\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\nx = n * m\\ny = 2\\nz = x // y\\nif x >= y:\\n\\tprint(z)\\nelse:\\n\\tprint(0)\\n\",\n \"(a, b) = map(int, input().split())\\nif a % 2 == 0 and b % 2 != 0:\\n\\tN = a / 2 * b\\nelif a % 2 != 0 and b % 2 == 0:\\n\\tN = b / 2 * a\\nelif a % 2 == 0 and b % 2 == 0:\\n\\tN = a * b / 2\\nelse:\\n\\tN = (a * b - 1) / 2\\nprint(str(int(N)))\\n\",\n \"(m, n) = list(map(int, input().split()))\\nprint(max(m // 2 * n + m % 2 * n // 2, n // 2 * m + n % 2 * m // 2))\\n\",\n \"m = ['0', '0']\\nm = input().split()\\nm[0] = int(m[0])\\nm[1] = int(m[1])\\nif m[0] > 0 and m[1] > 0 and (m[0] < 17) and (m[0] <= m[1]):\\n\\tprint(m[0] * m[1] // 2)\\n\",\n \"a = input()\\na = a.split()\\na1 = int(a[0])\\na2 = int(a[1])\\na3 = a1 * a2\\nrespuesta = a3 // 2\\nprint(respuesta)\\n\",\n \"(m, n) = map(int, input().split())\\nc = m * n\\nd = c // 2\\nprint(d)\\n\",\n \"import math\\ninp = input()\\nm = int(inp[0:inp.find(' ')])\\nn = int(inp[inp.find(' '):len(inp)])\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(n * (m - 1) / 2 + int(n / 2)))\\n\",\n \"[m, n] = list(map(int, input().split()))\\nprint(int(0.5 * m * n))\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\nn = M * (N // 2)\\nif N % 2 != 0:\\n\\tn += M // 2\\nprint(n)\\n\",\n \"while True:\\n\\t(m, n) = input().split(' ')\\n\\tif int(m) >= 1 and int(m) <= int(n) and (int(n) <= 16):\\n\\t\\tbreak\\nprint(int(m) * int(n) // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nsq_user = M * N\\nsq_dom = 1 * 2\\nprint(int(sq_user // sq_dom))\\n\",\n \"(rows, columns) = map(int, input().split())\\ntotal_squares = rows * columns\\nmax_dominoes = 0\\nwhile total_squares > 1:\\n\\tmax_dominoes += 1\\n\\ttotal_squares -= 2\\nprint(max_dominoes)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ntiles = m * n // 2\\nprint(tiles)\\n\",\n \"userinput = input()\\n(v1, v2) = userinput.split(' ')\\nv1 = int(v1)\\nv2 = int(v2)\\nvalue = 0\\nif v1 % 2 == 0 or v2 % 2 == 0:\\n\\tvalue = v1 * v2 / 2\\nelse:\\n\\tvalue = (v1 - 1) * v2 / 2\\n\\twhile v1 != 0 and v2 > 2:\\n\\t\\tv2 -= 2\\n\\t\\tvalue = value + 1\\nprint(int(value))\\n\",\n \"(M, N) = input().split()\\n(M, N) = [int(M), int(N)]\\nB = int(M * N / 2)\\nprint(B)\\n\",\n \"import sys\\n(M, N) = map(int, sys.stdin.readline().split())\\nmax_dom = M * N // 2\\nsys.stdout.write(str(max_dom))\\n\",\n \"A = input().split()\\nM = int(A[0])\\nN = int(A[1])\\nprint(M * N // 2)\\n\",\n \"import sys\\nimport math\\nimport array\\n(n, m) = map(int, input().split())\\nif n % 2 == 0:\\n\\tprint(int(n * m / 2))\\nelif m % 2 == 0:\\n\\tprint(int(n * m / 2))\\nelse:\\n\\tprint(int((n * m - 1) / 2))\\n\",\n \"k = input()\\nb = k.split(' ')\\na = []\\nfor i in b:\\n\\ta.append(int(i))\\nt = a[0] * a[1]\\nprint(t // 2)\\n\",\n \"inpt = list(map(int, input().split()))\\nprint(int(inpt[0] * inpt[1] / 2))\\n\",\n \"def main():\\n\\t(m, n) = list(map(int, input().split()))\\n\\tdomino = int(2)\\n\\tboard_size = m * n\\n\\tboard_size = int(board_size)\\n\\tif board_size % 2 == 0:\\n\\t\\tprint(int(board_size / domino))\\n\\telse:\\n\\t\\tboard_size -= 1\\n\\t\\tif board_size == 0:\\n\\t\\t\\tprint(0)\\n\\t\\telse:\\n\\t\\t\\tprint(int(board_size / domino))\\nmain()\\n\",\n \"w = input()\\nlista = w.split()\\nm = int(lista[0])\\nn = int(lista[1])\\nif n % 2 == 0:\\n\\tN = int(n * m / 2)\\nelse:\\n\\tN = int((n - 1) * m / 2 + m / 2)\\nprint(N, end='')\\n\",\n \"x = input('')\\nx = x.split()\\nlenth = int(x[0])\\nwidth = int(x[1])\\nprint(lenth * width // 2)\\n\",\n \"def count(m, n):\\n\\tc = 0\\n\\tc = m // 2 * n\\n\\tif int(m % 2) == 1:\\n\\t\\tc += n // 2\\n\\tprint(c)\\nmn = input().split()\\nm = int(mn[0])\\nn = int(mn[1])\\ncount(m, n)\\n\",\n \"(M, N) = map(int, input().split())\\nif M * N % 2 == 0:\\n\\tprint('{0:.0f}'.format(M * N / 2))\\nelse:\\n\\tprint(M * N // 2)\\n\",\n \"num = input()\\n(m, n) = num.split()\\nm = int(m)\\nn = int(n)\\na = m * n\\nd = a // 2\\nprint(d)\\n\",\n \"(n, m) = [int(info) for info in input().split(' ')]\\nprint(n * m // 2)\\n\",\n \"(n, m) = list(map(int, input().split()))\\nr = 0\\nif n == 1 or m == 1:\\n\\tprint(n * m // 2)\\nelse:\\n\\tif n % 2 != 0:\\n\\t\\tn -= 1\\n\\t\\tr = m // 2\\n\\telif m % 2 != 0:\\n\\t\\tm -= 1\\n\\t\\tr = n // 2\\n\\tprint(n * m // 2 + r)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ns = 2 * 1\\np = m * n // 2\\nprint(p)\\n\",\n \"import math\\n(m, n) = map(int, input('').split())\\nboard_area = m * n\\nnum_of_tiles = math.floor(board_area / 2)\\nprint(num_of_tiles)\\n\",\n \"(M, N) = map(int, input().split())\\nx = M * N // 2\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\nmt = m * n\\nl = mt // 2\\nprint(l)\\n\",\n \"x = str(input())\\nn = str(x[-2:])\\nm = str(x[:2])\\nn = int(n)\\nm = int(m)\\nw = n * m\\nd = int(w / 2)\\nprint(d)\\n\",\n \"def main(n, m):\\n\\ti = 1\\n\\twhile True:\\n\\t\\tif i * 2 <= n * m:\\n\\t\\t\\ti += 1\\n\\t\\telse:\\n\\t\\t\\tbreak\\n\\treturn i - 1\\nstr = input()\\n(n, m) = map(int, str.split(' '))\\nans = main(n, m)\\nprint(ans)\\n\",\n \"(num1, num2) = map(int, input().split())\\nprint(num1 * num2 // 2)\\n\",\n \"(n, k) = map(int, input().split())\\na = n * k\\nprint(int(a / 2))\\n\",\n \"import math\\n(x, y) = map(int, input().split())\\nc = math.floor(x / 2)\\nr = math.floor(y / 1)\\ncount = c * r\\nleft = 0\\nif x % 2 == 1:\\n\\tleft = math.floor(y / 2)\\nprint(count + left)\\n\",\n \"(m, n) = input().split()\\nmul = int(m) * int(n)\\nprint(mul // 2)\\n\",\n \"board = list(map(int, input().split()))\\nl = board[0]\\nw = board[1]\\nif l == 1 or w == 1:\\n\\tans = l * w // 2\\nelif l % 2 == 0 and w % 2 == 0:\\n\\tans = l * w // 2\\nelif l * w % 2 == 0:\\n\\tif l % 2 != 0:\\n\\t\\tans = (l - 1) // 2 * w + w // 2\\n\\telse:\\n\\t\\tans = (w - 1) // 2 * l + l // 2\\nelse:\\n\\tans = (l - 1) // 2 * (w - 1) + (w - 1) // 2 + (l - 1) // 2\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split())\\nx = m * n\\nif x % 2 == 0:\\n\\tprint(int(x / 2))\\nelse:\\n\\tprint(int(x / 2 - 0.5))\\n\",\n \"integers = input().split()\\nm = int(integers[0])\\nn = int(integers[1])\\nans = int(m * n / 2)\\nprint(ans)\\n\",\n \"import math\\n(a, b) = input().split()\\na = int(a)\\nb = int(b)\\narea = a * b\\nappro = math.floor(area / 2)\\nprint(int(appro))\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nt = a\\nc = 0\\nwhile t >= 2:\\n\\tt = t - 2\\n\\tc += 1\\nprint(c)\\n\",\n \"m_n = str(input()).split(' ')\\nm = int(m_n[0])\\nn = int(m_n[1])\\nmxn = m * n\\nif mxn % 2 == 0:\\n\\tprint(int(mxn / 2))\\nelse:\\n\\tprint(int((mxn - 1) / 2))\\n\",\n \"line = str(input())\\nM = int(line.split()[0])\\nN = int(line.split()[1])\\nnumber = 0\\nif M % 2 == 0:\\n\\tnumber = N * (M / 2)\\nelse:\\n\\tnumber = N * (M // 2) + N // 2\\nprint(int(number))\\n\",\n \"boardSize = []\\ntotal = 0\\nboardSize = input().split(' ')\\nboardSize[0] = int(boardSize[0])\\nboardSize[1] = int(boardSize[1])\\nunalteredBoard = boardSize[0]\\nnewBoard = [1, boardSize[1]]\\nif boardSize[0] % 2 == 1:\\n\\tboardSize[0] -= 1\\n\\tnewBoard = [1, boardSize[1]]\\n\\tunalteredBoard = boardSize[0] + 1\\n\\ttotal += newBoard[1] // 2\\nif boardSize[1] % 2 == 1:\\n\\tboardSize[1] -= 1\\n\\tnextBoard = [1, unalteredBoard]\\n\\tif newBoard[1] % 2 == 0:\\n\\t\\tnextBoard = [1, unalteredBoard - 1]\\n\\ttotal += nextBoard[1] // 2\\nsizeOne = boardSize[1] / 2 * boardSize[0]\\nsizeTwo = boardSize[0] / 2 * boardSize[1]\\ntotal += max([sizeOne, sizeTwo])\\nprint(int(total))\\n\",\n \"(m, n) = map(int, input().split())\\narea = n * m\\no = area / 2\\nif area % 2 == 0:\\n\\tprint(int(o))\\nelse:\\n\\to = area // 2\\n\\tprint(o)\\n\",\n \"(m, n) = input().split(' ')\\nmax = int(m) * int(n) // 2\\nprint(max)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nprint(int(m * n / 2) if (m % 2 and n % 2) == 0 else int((m * n - 1) / 2))\\n\",\n \"(m, n) = input().split()\\nsquares = int(m) * int(n)\\nif squares % 2 == 0:\\n\\tprint(int(squares / 2))\\nelse:\\n\\tprint(int((squares - 1) / 2))\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n(m, n) = map(int, input().split())\\nprint(m * n // 2)\\n\",\n \"dim = [int(a) for a in input().split()]\\nans = 0\\nif dim[0] % 2 != 0 and dim[1] % 2 != 0:\\n\\tans = int(((dim[0] - 1) * dim[1] + (dim[1] - 1)) / 2)\\nelse:\\n\\tans = int(dim[0] * dim[1] / 2)\\nprint(ans)\\n\",\n \"input1 = input().split()\\nm = int(input1[0])\\nn = int(input1[1])\\narea = m * n\\namount = area // 2\\nprint(amount)\\n\",\n \"(a, b) = map(int, input().split())\\nd = 0\\nd = a * b / 2\\nprint(int(d))\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\ta = m * n // 2\\nelif n % 2 == 0:\\n\\ta = m * n // 2\\nelse:\\n\\ta = max(n // 2 * m + m // 2, m // 2 * n + n // 2)\\nprint(a)\\n\",\n \"import os\\nimport sys\\n\\ndef get_int():\\n\\treturn int(input())\\n\\ndef get_ints():\\n\\treturn map(int, input().split())\\n\\ndef get_strs():\\n\\treturn input().split()\\n\\ndef get_float():\\n\\treturn float(input())\\n\\ndef get_floats():\\n\\treturn map(float, input().split())\\n\\ndef list_strs():\\n\\treturn list(input().split())\\n\\ndef list_ints():\\n\\treturn list(map(int, input().split()))\\n\\ndef list_floats():\\n\\treturn list(map(float, input.split()))\\n\\ndef post(x):\\n\\tprint(x, end=' ')\\n(n, m) = get_ints()\\nprint(n * m // 2)\\n\",\n \"inp = list(map(int, input().split()))\\nM = inp[0]\\nN = inp[1]\\nprint(M * N // 2)\\n\",\n \"def main():\\n\\t(m, n) = map(int, input().split(' '))\\n\\tat = m * n\\n\\tprint(at // 2)\\nmain()\\n\",\n \"(m, n) = map(int, input().split())\\nstandard_area = 2 * 1\\narea = m * n\\nprint(area // standard_area)\\n\",\n \"(M, N) = map(int, input().split())\\nA = M * N\\na = 2\\nprint(A // a)\\n\",\n \"num_list = input().split()\\narea = 1\\nfor num in num_list:\\n\\tarea *= int(num)\\nprint(area // 2)\\n\",\n \"(n, m) = map(int, input().split())\\na1 = m // 2 * n + m % 2 * (n // 2)\\na2 = n // 2 * m + n % 2 * (m // 2)\\nans = max(a1, a2)\\nprint(ans)\\n\",\n \"def isolate(string):\\n\\tnumlist = []\\n\\tu = len(string)\\n\\tj = 0\\n\\tfor i in range(0, u):\\n\\t\\tcharacter = string[i]\\n\\t\\tif character == ' ':\\n\\t\\t\\tpick = int(string[j:i])\\n\\t\\t\\tnumlist.append(pick)\\n\\t\\t\\tj = i + 1\\n\\t\\telif i == u - 1:\\n\\t\\t\\tpick = int(string[j:i + 1])\\n\\t\\t\\tnumlist.append(pick)\\n\\t\\t\\tj = i + 1\\n\\treturn numlist\\nfr1 = str(input(''))\\np = isolate(fr1)\\nM = int(p[0])\\nN = int(p[1])\\nprint(M * N // 2)\\n\",\n \"st = input()\\nst = st.split()\\nm = st[0]\\nn = st[1]\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0:\\n\\ta = int(n * m / 2)\\nelse:\\n\\tx = (m - 1) / 2\\n\\ta = int(x * n + n // 2)\\nprint(a)\\n\",\n \"(m, n) = map(int, input().split(' '))\\np = m * n\\ndiv = p // 2\\nprint(div)\\n\",\n \"(m, n) = map(int, input().split())\\ntot = m * n\\nif tot % 2 == 0:\\n\\tprint(tot // 2)\\nelif tot % 2 != 0:\\n\\tprint(tot // 2)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\nd = 2 * 1\\na = s // d\\nprint(a)\\n\",\n \"inputs = input().split(' ')\\nnb_case = int(inputs[0]) * int(inputs[1])\\noutputs = nb_case / 2\\nprint(int(outputs))\\n\",\n \"(M, N) = [int(i) for i in input().strip().split()]\\nprint(M * N // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nl = 0\\nif n % 2 == 0:\\n\\tl = n // 2 * m\\nelse:\\n\\tl = n // 2 * m + m // 2\\nprint(l)\\n\",\n \"(a, b) = map(int, input().split())\\nc = max(a, b)\\nd = min(a, b)\\nif c % 2 == 0:\\n\\tprint(int(c / 2 * d))\\nelse:\\n\\tprint(int((c - 1) / 2 * d + d // 2))\\n\",\n \"def domino(n, m):\\n\\tnumber = 0\\n\\tif n % 2 == 1 and m % 2 == 1:\\n\\t\\tif n == m == 1:\\n\\t\\t\\tnumber = 0\\n\\t\\telse:\\n\\t\\t\\tnumber = n * (m // 2) + n // 2\\n\\telse:\\n\\t\\tnumber = n * m // 2\\n\\tprint(number)\\n(n, m) = map(int, input().split())\\ndomino(n, m)\\n\",\n \"himpunan_angka = []\\nfor i in range(1, 17):\\n\\thimpunan_angka.append(i)\\nwhile True:\\n\\tm_dan_n = input().split(' ')\\n\\tm = int(m_dan_n[0])\\n\\tn = int(m_dan_n[1])\\n\\tif m not in himpunan_angka or n not in himpunan_angka or (m <= n) == False:\\n\\t\\tcontinue\\n\\tbreak\\nmn = m * n\\nmaks_domino = mn // 2\\nprint(maks_domino)\\n\",\n \"sizeInput = input()\\nlistInput = sizeInput.split()\\nboardSize = int(listInput[0]) * int(listInput[1])\\nmaxpossibleDomino = boardSize // 2\\nprint(maxpossibleDomino)\\n\",\n \"a = list(map(int, input().split(' ')))\\n\\ndef intmin(a, b):\\n\\tprint(a if a < b else b)\\nintmin(a[0] // 2 * a[1] + (a[1] // 2 if a[0] % 2 == 1 else 0), a[1] // 2 * a[0] + (a[0] // 2 if a[1] % 2 == 1 else 0))\\n\",\n \"x = input().split()\\na = int(x[0])\\nb = int(x[1])\\nc = a * b\\nn = int(c / 2)\\nprint(n)\\n\",\n \"in_str = input().split(' ')\\nM = int(in_str[0])\\nN = int(in_str[1])\\nprint(int(M * N / 2))\\n\",\n \"first = input()\\nF = [int(x) for x in first.split()]\\nprint(F[0] * F[1] // 2)\\n\",\n \"x0 = input()\\nx1 = x0.split(' ')\\nnew_list = list()\\nfor i in x1:\\n\\tnew_list.append(int(i))\\na = int(new_list[0])\\nb = int(new_list[1])\\nif not a > b:\\n\\tif a >= 1 and b >= 1 and (a <= 16) and (b <= 16):\\n\\t\\tc = a * b // 2\\n\\t\\tprint(c)\\n\",\n \"(n, m) = map(int, input().split())\\nx = m // 1\\ny = n // 2\\nx1 = m // 1 * n // 2\\nx2 = m // 2 * n // 1\\nnumber = x1\\nif x2 > number:\\n\\tnumber = x2\\nprint(number)\\n\",\n \"(n, m) = map(int, input().split())\\nres = n * m\\nans = res // 2\\nprint(ans)\\n\",\n \"(a, b) = map(int, input().split())\\nprint(int((a * b - 1) / 2)) if a % 2 and b % 2 else print(int(a * b / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nc = int(m) * int(n)\\nr = int(c) / 2\\nprint(int(r))\\n\",\n \"N = input()\\nn = int(N.split()[0]) * int(N.split()[1])\\nif n % 2 == 0:\\n\\tprint(int(n / 2))\\nelse:\\n\\tprint(int((n - 1) / 2))\\n\",\n \"(a, b) = map(int, input().split())\\nif a % 2 == 0:\\n\\tres = a / 2 * b\\nelif b % 2 == 0:\\n\\tres = b / 2 * a\\nelse:\\n\\tres = int(a / 2) * b + int(b / 2)\\nres = int(res)\\nprint(res)\\n\",\n \"def domino(m, n):\\n\\tif m % 2 == 0 or n % 2 == 0:\\n\\t\\treturn n * m / 2\\n\\telse:\\n\\t\\treturn (m - 1) * (n - 1) / 2 + n // 2 + m // 2\\nargs = input().split()\\nm = int(args[0])\\nn = int(args[1])\\nprint(int(domino(m, n)))\\n\",\n \"(lambda y: print(y[0] * y[1] // 2))(list(map(int, input().split())))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nif 1 <= M <= N <= 16:\\n\\tK = M * N\\nprint(int(K / 2))\\n\",\n \"first_str = input().split(' ')\\nm = int(first_str[0])\\nn = int(first_str[1])\\nboard_area = n * m\\ndomino_area = 2\\ndomino_num = 0\\nif board_area % domino_area != 0:\\n\\tboard_area -= 1\\n\\tdomino_num = board_area / domino_area\\nelse:\\n\\tdomino_num = board_area / domino_area\\nprint(int(domino_num))\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nO = M * N / 2\\nP = math.floor(O)\\nprint(int(P))\\n\",\n \"input_value = input().split()\\nm = int(input_value[0])\\nn = int(input_value[1])\\ndominos = 0\\npom = [[0 for x in range(n)] for y in range(m)]\\nif n <= 1 and m <= 1:\\n\\tdominos = 0\\nelse:\\n\\tif n > 1:\\n\\t\\tfor i in range(m):\\n\\t\\t\\tfor o in range(n - 1):\\n\\t\\t\\t\\tif pom[i][o] == 0 and pom[i][o + 1] == 0:\\n\\t\\t\\t\\t\\tpom[i][o] = 1\\n\\t\\t\\t\\t\\tpom[i][o + 1] = 1\\n\\t\\t\\t\\t\\tdominos += 1\\n\\tif m > 1:\\n\\t\\tfor i in range(m - 1):\\n\\t\\t\\tfor o in range(n):\\n\\t\\t\\t\\tif pom[i][o] == 0 and pom[i + 1][o] == 0:\\n\\t\\t\\t\\t\\tpom[i][o] = 1\\n\\t\\t\\t\\t\\tpom[i + 1][o] = 1\\n\\t\\t\\t\\t\\tdominos += 1\\nprint(dominos)\\n\",\n \"(a, b) = (int(s) for s in input().split())\\ns = a * b\\nprint(s // 2)\\n\",\n \"(d, m) = input().split()\\nprint(int(d) * int(m) // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nresult = a * b / 2\\nprint(int(result))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nresult = m * n / 2\\nprint(int(result))\\n\",\n \"coords = list(map(int, input().split()))\\n(x, y) = (coords[0], coords[1])\\nrezult = 0\\nrezult += x // 2 * y\\nif x % 2 == 1:\\n\\trezult += y // 2\\nprint(rezult)\\n\",\n \"x = input()\\ntab = x.split(' ')\\nt = int(tab[0]) * int(tab[1])\\nres = t / 2\\nprint(int(res))\\n\",\n \"(M, N) = map(eval, input().split())\\nif M % 2 == 0 or N % 2 == 0:\\n\\tprint(int(M * N / 2))\\nelse:\\n\\tprint(int(M * N / 2 - 1 / 2))\\n\",\n \"import math\\n(M, N) = [int(n) for n in input().split()]\\nprint(M * N // 2)\\n\",\n \"i = input().split()\\nM = int(i[0])\\nN = int(i[1])\\narea = M * N\\nprint(area // 2)\\n\",\n \"array = input().split()\\nlength = int(array[0])\\nwidth = int(array[1])\\narea = length * width\\nanswer = area // 2\\nprint(answer)\\n\",\n \"size = input().split(' ')\\n(m, n) = (int(size[0]), int(size[1]))\\nTwoSide = m // 2\\nOneSide = n // 2\\nTotalDominos = TwoSide * n\\nif m % 2 != 0:\\n\\tTotalDominos += OneSide\\nprint(TotalDominos)\\n\",\n \"m = input()\\ns = m.split()\\nM = int(s[0])\\nN = int(s[1])\\nif M * N % 2 == 0:\\n\\ta = int(M * N / 2)\\nelse:\\n\\ta = int((M * N - 1) / 2)\\nprint(a)\\n\",\n \"z = input().split(' ')\\nm = int(z[0])\\nn = int(z[1])\\nprint(m * n // 2)\\n\",\n \"def fun():\\n\\t(n, m) = map(int, input().split())\\n\\tprint(n * m // 2)\\nfun()\\n\",\n \"def dominos():\\n\\tm_n = [int(x) for x in input().split()]\\n\\tsize = m_n[0] * m_n[1]\\n\\tprint(size // 2)\\ndominos()\\n\",\n \"(M, N) = str.split(input())\\nM = int(M)\\nN = int(N)\\nif M % 2 == 0 or N % 2 == 0:\\n\\tt = M * N / 2\\nelse:\\n\\tt = (M * N - 1) / 2\\nprint(int(t))\\n\",\n \"from functools import reduce\\nprint(reduce(lambda x, y: x * y, map(int, input().split())) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nx = n / 2\\ny = n // 2\\nz1 = m * n\\nz2 = m * y\\nif x == y:\\n\\tprint(z2)\\nelif m < 2:\\n\\tprint(y)\\nelif z1 % 2 == 0:\\n\\tprint(z1 // 2)\\nelse:\\n\\tw = z1 // 2\\n\\tprint(w)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m * n % 2 == 0 and 1 <= m <= n <= 16:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(m * n / 2))\\n\",\n \"(w1, w2) = map(int, input().split())\\nprint(int(w1 * w2 / 2))\\n\",\n \"do = list(map(int, input().rstrip().split()))\\nm = do[0]\\nn = do[1]\\nans = 0\\nprint(int(n * m / 2))\\n\",\n \"ar1 = input().split()\\nprint(int(ar1[0]) * int(ar1[1]) // 2)\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\nc = a * (b // 2) + b % 2 * (a // 2)\\nd = a // 2 * b + a % 2 * (b // 2)\\nif c > d:\\n\\tprint(c)\\nelse:\\n\\tprint(d)\\n\",\n \"x = input().split(' ')\\ny = int(x[0]) * int(x[1])\\nif y % 2 != 0:\\n\\ty -= 1\\n\\tans = y / 2\\nelse:\\n\\tans = y / 2\\nprint(int(ans))\\n\",\n \"(length, breadth) = map(int, input().split())\\nprint(int(length * breadth / 2))\\n\",\n \"(M, N) = map(int, input().split())\\nif M % 2 == 0:\\n\\ts = M // 2 * N\\nelif N % 2 == 0:\\n\\ts = N // 2 * M\\nelse:\\n\\ts = N // 2 * M + M // 2\\nprint(s)\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nk = M * N\\nnum = k // 2\\nprint(num)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\nd = 0\\nif s % 2 == 0:\\n\\td = s / 2\\nelse:\\n\\td = (s - 1) / 2\\nprint(int(d))\\n\",\n \"s = input()\\ns = s.split()\\nn = int(s[0]) * int(s[1])\\nresult = n // 2\\nprint(result)\\n\",\n \"from sys import stdin, stdout\\n(M, N) = map(int, stdin.readline().rstrip().split())\\narea = M * N\\namount_of_dominos = area // 2\\nstdout.write(str(amount_of_dominos))\\n\",\n \"import math\\ns = input()\\ns = s.split(' ')\\n(a, b) = (int(s[0]), int(s[1]))\\na = a * b\\nprint(math.floor(a / 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m * n % 2 == 0:\\n\\tprint('{0:.0f}'.format(m * n / 2))\\nelse:\\n\\tprint('{0:.0f}'.format((m * n - 1) / 2))\\n\",\n \"def main():\\n\\t_ = input().split(' ')\\n\\t(n, m) = [int(i) for i in _]\\n\\tif n < 1 or m < 1:\\n\\t\\treturn 0\\n\\tif n == 1 and m == 1:\\n\\t\\treturn 0\\n\\tif n == 1:\\n\\t\\treturn m // 2\\n\\tif m == 1:\\n\\t\\treturn n // 2\\n\\tif n % 2 == 0 or m % 2 == 0:\\n\\t\\treturn n * m // 2\\n\\telse:\\n\\t\\tresult = (n - 1) * (m - 1) // 2\\n\\t\\tif n > 1 and m > 1:\\n\\t\\t\\tresult += (n + m - 1) // 2\\n\\t\\treturn result\\n\\treturn None\\nprint(main())\\n\",\n \"def convert(arr):\\n\\tarr = arr.split(' ')\\n\\tfor i in range(len(arr)):\\n\\t\\tarr[i] = int(arr[i])\\n\\treturn arr\\narea = input()\\ndim = convert(area)\\nprint(int(dim[0] * dim[1] / 2))\\n\",\n \"numbers = [int(x) for x in input().split()]\\nsquares = numbers[0] * numbers[1]\\nif squares % 2 == 0:\\n\\tprint(int(squares / 2))\\nelse:\\n\\tprint(int((squares - 1) / 2))\\n\",\n \"from sys import stdin, stdout\\nimport bisect\\nfrom bisect import bisect_left as bl\\nfrom bisect import bisect_right as br\\nimport itertools\\nfrom collections import Counter\\nimport collections\\nimport math\\nimport heapq\\nimport re\\n\\ndef modinv(n, p):\\n\\treturn pow(n, p - 2, p)\\n\\ndef cin():\\n\\treturn map(int, sin().split())\\n\\ndef ain():\\n\\treturn list(map(int, sin().split()))\\n\\ndef sin():\\n\\treturn input()\\n\\ndef inin():\\n\\treturn int(input())\\n\\ndef Divisors(n):\\n\\tl = []\\n\\tfor i in range(1, int(math.sqrt(n) + 1)):\\n\\t\\tif n % i == 0:\\n\\t\\t\\tif n // i == i:\\n\\t\\t\\t\\tl.append(i)\\n\\t\\t\\telse:\\n\\t\\t\\t\\tl.append(i)\\n\\t\\t\\t\\tl.append(n // i)\\n\\treturn l\\n\\ndef most_frequent(list):\\n\\treturn max(set(list), key=list.count)\\n\\ndef GCD(x, y):\\n\\twhile y:\\n\\t\\t(x, y) = (y, x % y)\\n\\treturn x\\n\\ndef ncr(n, r, p):\\n\\tt = fact[n] * (ifact[r] * ifact[n - r] % p) % p\\n\\treturn t\\n\\ndef Convert(string):\\n\\tli = list(string.split(''))\\n\\treturn li\\n\\ndef SieveOfEratosthenes(n):\\n\\tglobal prime\\n\\tprime = [True for i in range(n + 1)]\\n\\tp = 2\\n\\twhile p * p <= n:\\n\\t\\tif prime[p] == True:\\n\\t\\t\\tfor i in range(p * p, n + 1, p):\\n\\t\\t\\t\\tprime[i] = False\\n\\t\\tp += 1\\n\\tf = []\\n\\tfor p in range(2, n):\\n\\t\\tif prime[p]:\\n\\t\\t\\tf.append(p)\\n\\treturn f\\nprime = []\\nq = []\\n\\ndef dfs(n, d, v, c):\\n\\tglobal q\\n\\tv[n] = 1\\n\\tx = d[n]\\n\\tq.append(n)\\n\\tj = c\\n\\tfor i in x:\\n\\t\\tif i not in v:\\n\\t\\t\\tf = dfs(i, d, v, c + 1)\\n\\t\\t\\tj = max(j, f)\\n\\treturn j\\n\\ndef main():\\n\\t(n, m) = map(int, input().split())\\n\\tif n > m:\\n\\t\\t(n, m) = (m, n)\\n\\tif n == 1:\\n\\t\\tif m == 1:\\n\\t\\t\\tprint(0)\\n\\t\\telse:\\n\\t\\t\\tprint(m // 2)\\n\\telif m % 2 == 0:\\n\\t\\tprint(m // 2 * n)\\n\\telse:\\n\\t\\tprint(m // 2 * n + n // 2)\\npy2 = round(0.5)\\nif py2:\\n\\tfrom future_builtins import ascii, filter, hex, map, oct, zip\\n\\trange = xrange\\nimport os, sys\\nfrom io import IOBase, BytesIO\\nBUFSIZE = 8192\\n\\nclass FastIO(BytesIO):\\n\\tnewlines = 0\\n\\n\\tdef __init__(self, file):\\n\\t\\tself._file = file\\n\\t\\tself._fd = file.fileno()\\n\\t\\tself.writable = 'x' in file.mode or 'w' in file.mode\\n\\t\\tself.write = super(FastIO, self).write if self.writable else None\\n\\n\\tdef _fill(self):\\n\\t\\ts = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))\\n\\t\\tself.seek((self.tell(), self.seek(0, 2), super(FastIO, self).write(s))[0])\\n\\t\\treturn s\\n\\n\\tdef read(self):\\n\\t\\twhile self._fill():\\n\\t\\t\\tpass\\n\\t\\treturn super(FastIO, self).read()\\n\\n\\tdef readline(self):\\n\\t\\twhile self.newlines == 0:\\n\\t\\t\\ts = self._fill()\\n\\t\\t\\tself.newlines = s.count(b'\\\\n') + (not s)\\n\\t\\tself.newlines -= 1\\n\\t\\treturn super(FastIO, self).readline()\\n\\n\\tdef flush(self):\\n\\t\\tif self.writable:\\n\\t\\t\\tos.write(self._fd, self.getvalue())\\n\\t\\t\\t(self.truncate(0), self.seek(0))\\n\\nclass IOWrapper(IOBase):\\n\\n\\tdef __init__(self, file):\\n\\t\\tself.buffer = FastIO(file)\\n\\t\\tself.flush = self.buffer.flush\\n\\t\\tself.writable = self.buffer.writable\\n\\t\\tif py2:\\n\\t\\t\\tself.write = self.buffer.write\\n\\t\\t\\tself.read = self.buffer.read\\n\\t\\t\\tself.readline = self.buffer.readline\\n\\t\\telse:\\n\\t\\t\\tself.write = lambda s: self.buffer.write(s.encode('ascii'))\\n\\t\\t\\tself.read = lambda : self.buffer.read().decode('ascii')\\n\\t\\t\\tself.readline = lambda : self.buffer.readline().decode('ascii')\\n(sys.stdin, sys.stdout) = (IOWrapper(sys.stdin), IOWrapper(sys.stdout))\\ninput = lambda : sys.stdin.readline().rstrip('\\\\r\\\\n')\\nmain()\\n\",\n \"square = input()\\nsquarelist = square.split()\\nrest = int(squarelist[0]) * int(squarelist[1]) % 2\\nif int(rest) > 0:\\n\\toutput = (int(squarelist[0]) * int(squarelist[1]) - 1) / 2\\n\\tprint(int(output))\\nelse:\\n\\toutput = int(squarelist[0]) * int(squarelist[1]) / 2\\n\\tprint(int(output))\\n\",\n \"count = 0\\nrazmery = input()\\nmassiv = razmery.split()\\nm = int(massiv[0])\\nn = int(massiv[1])\\ni = 2 * 1\\ns = m * n\\nwhile i <= s:\\n\\tif i <= s:\\n\\t\\tcount += 1\\n\\t\\ti = i + 2\\nprint(count)\\n\",\n \"def main():\\n\\ta = input().split(' ')\\n\\tm = int(a[0])\\n\\tn = int(a[1])\\n\\tprint(m * n // 2)\\nmain()\\n\",\n \"L = list(map(int, input().split()))\\na = L[0]\\nb = int(L[1] / 2)\\nif L[1] % 2 == 0:\\n\\tc = 0\\nelse:\\n\\tc = int(L[0] / 2)\\nnum = a * b + c\\nprint(int(num))\\n\",\n \"board = input().split()\\nboard[0] = int(board[0])\\nboard[1] = int(board[1])\\ns = board[0] * board[1]\\nif s % 2 == 0:\\n\\tans = s / 2\\nelse:\\n\\tans = (s - 1) / 2\\nprint(round(ans))\\n\",\n \"def number_dominoes(M, N):\\n\\tarea = M * N\\n\\tif area % 2 == 0:\\n\\t\\treturn area / 2\\n\\telse:\\n\\t\\treturn (area - 1) / 2\\n\\ndef main():\\n\\t(M, N) = input().split()\\n\\tM = int(M)\\n\\tN = int(N)\\n\\tn_d = number_dominoes(M, N)\\n\\tn_d = int(n_d)\\n\\tprint(n_d)\\nmain()\\n\",\n \"def operation(a, b):\\n\\tprint(int(a * b / 2))\\n(a, b) = map(int, input().split())\\noperation(a, b)\\n\",\n \"a = input().split(sep=' ')\\nprint(int(a[0]) * int(a[1]) // 2)\\n\",\n \"(p, q) = map(int, input().split())\\nprint(p * q // 2)\\n\",\n \"(K, N) = map(int, input().split())\\n_M = K * N\\n_res = _M // 2\\nprint(_res)\\n\",\n \"(m, n) = map(int, input().split())\\ntotal = 0\\nwhile m > 1 or n > 1:\\n\\ta = max(m, n)\\n\\tb = min(m, n)\\n\\ttotal = total + b\\n\\tm = a - 2\\n\\tn = b\\nprint(total)\\n\",\n \"(M, N) = list(map(int, input().split()))\\nif M % 2 == 0 and N % 2 == 0:\\n\\tprint(M * N // 2)\\nelif M % 2 == 0 and N % 2 != 0 or (M % 2 != 0 and N % 2 == 0):\\n\\tprint(M * N // 2)\\nelif M % 2 != 0 and N % 2 != 0:\\n\\tif M > N:\\n\\t\\tprint(M * (N - 1) // 2 + (M - 1) // 2)\\n\\telse:\\n\\t\\tprint(N * (M - 1) // 2 + (N - 1) // 2)\\n\",\n \"ans = 0\\n(n, m) = input().split()\\nx = int(n) / 2\\ny = int(m) / 2\\nans = x * int(m)\\nif x * 2 < int(n):\\n\\tans += y\\nprint(int(ans))\\n\",\n \"a = [int(i) for i in input().split(' ')]\\narea = a[0] * a[1]\\nprint(area // 2)\\n\",\n \"(n, m) = tuple(input().split())\\nprint(int(n) * int(m) // 2)\\n\",\n \"wer = input()\\nlist_we_use = wer.split(' ')\\nr = []\\nfor i in list_we_use:\\n\\tr.append(int(i))\\nt = r[0] * r[1]\\nprint(t // 2)\\n\",\n \"(s, b) = [int(x) for x in input().split()]\\nd = max(s, b)\\nk = min(s, b)\\nl = 0\\nif k >= 2:\\n\\tif k >= 2 and k % 2 == 1:\\n\\t\\tl = d * (k // 2) + d // 2\\n\\telse:\\n\\t\\tl = d * (k // 2)\\nelse:\\n\\tl = d // 2\\nprint(l)\\n\",\n \"numbers = input().split()\\na = int(numbers[0])\\nb = int(numbers[1])\\nm = min(a, b)\\nn = max(a, b)\\nif m == 0:\\n\\tprint(0)\\nelif m == 1:\\n\\tprint(n // 2)\\nelse:\\n\\tprint(n * (m // 2) + m % 2 * (n // 2))\\n\",\n \"(m, n) = map(float, input().split())\\nan = int(m * n // 2.0)\\nprint(an)\\n\",\n \"(x, y) = map(int, input().split())\\nif x == 1:\\n\\tprint(int(y / 2))\\nif x % 2 == 0:\\n\\tprint(int(x / 2 * y))\\nelif y == 1 and x != 1:\\n\\tprint(int((x - 1) / 2 * y))\\nelif x != 1:\\n\\tprint(int((x - 1) / 2 * y + int(y / 2)))\\n\",\n \"(M, N) = map(int, input().split())\\nif M * N % 2 == 0:\\n\\ta = M * N // 2\\nelse:\\n\\ta = M * N // 2\\nprint(a)\\n\",\n \"(M, N) = list(map(int, input().split()))\\nif 1 <= M <= N <= 16:\\n\\tArea = M * N\\n\\tdominoes = int(Area / 2)\\n\\tprint(dominoes)\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\nresult = n * m // 2\\nprint(result)\\n\",\n \"(n, m) = tuple((int(x) for x in input().split()))\\n(ns, nr) = divmod(n, 2)\\n(ms, mr) = divmod(m, 2)\\nprint(ms * n + mr * ns)\\n\",\n \"inc = 0\\ndomino = 2\\n(num1, num2) = map(int, input().split())\\narea = num1 * num2\\nif num1 >= 1 or num2 >= 1 or num1 <= 16 or (num2 <= 16):\\n\\tfor x in range(area):\\n\\t\\tif area >= 2:\\n\\t\\t\\tarea = area - domino\\n\\t\\t\\tinc += 1\\nprint(inc)\\n\",\n \"totIn = str(input())\\ntotList = totIn.split()\\nm = int(totList[0])\\nn = int(totList[1])\\ntotSquare = m * n\\nplacedDominos = 0\\nfor i in range(0, totSquare):\\n\\twhile totSquare >= 2:\\n\\t\\ttotSquare -= 2\\n\\t\\tplacedDominos += 1\\nprint(placedDominos)\\n\",\n \"(m, n) = input().split()\\nm1 = int(m)\\nm2 = int(n)\\np = m1 * m2\\nt = int(p / 2)\\nprint(t)\\n\",\n \"(x, y) = [int(x) for x in input().split()]\\narea_of_rectangle = x * y\\nCan_fit = 2\\nnum_of_dominoes = area_of_rectangle // Can_fit\\nprint(num_of_dominoes)\\n\",\n \"N = input().split()\\nfor i in range(len(N)):\\n\\tN[i] = int(N[i])\\nx = N[0] * N[1]\\nk = x // 2\\nprint(k)\\n\",\n \"(m, n) = input().split()\\n(m, n) = (int(m), int(n))\\ns = 0\\nr = n * m\\nwhile r - 2 >= 0:\\n\\tr = r - 2\\n\\ts += 1\\nprint(s)\\n\",\n \"(a, b) = [int(i) for i in input().split()]\\nif a * b % 2 == 0:\\n\\tprint(a * b // 2)\\nelse:\\n\\tprint((a * b - 1) // 2)\\n\",\n \"l1 = [int(x) for x in input().split()]\\narea = l1[0] * l1[1]\\nif area % 2 == 0:\\n\\tprint(int(area / 2))\\nelse:\\n\\tprint(int((area - 1) / 2))\\n\",\n \"(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nx_x = x % 2\\ny_y = y % 2\\nif x_x + y_y == 2:\\n\\tz = (x * y - 1) / 2\\nelse:\\n\\tz = x * y / 2\\nprint(int(z))\\n\",\n \"(m, n) = list(map(int, input().split()))\\ncount = 0\\nfor raw in range(n):\\n\\tcount += m / 2\\nprint(int(count))\\n\",\n \"(M, N) = map(int, input().split())\\nasd = M * N // 2\\nprint(asd)\\n\",\n \"(m, n) = map(int, input().split())\\nc = 0\\nr = n % 2\\nq = (n - r) // 2\\nc = q * m\\nif r == 1:\\n\\tc += m // 2\\nprint(c)\\n\",\n \"aux = input()\\naux = aux.split()\\nn = int(aux[0])\\nm = int(aux[1])\\nans = n * m // 2\\nprint(ans)\\n\",\n \"number = input().split()\\nnum1 = int(number[0])\\nnum2 = int(number[1])\\nr = num1 * num2\\nprint(r // 2)\\n\",\n \"str_0 = input()\\nlist_0 = str_0.split(' ')\\nm = int(list_0[0])\\nn = int(list_0[1])\\nn_1 = n // 2\\nif n % 2 == 0:\\n\\tprint(n_1 * m)\\nelse:\\n\\tprint(n_1 * m + m // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\narea_left = m * n\\ntotal = 0\\nwhile area_left >= 2:\\n\\tarea_left -= 2\\n\\ttotal += 1\\nprint(total)\\n\",\n \"import math\\n(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nprint(math.floor(a * b / 2))\\n\",\n \"from math import floor\\n\\ndef cin(func):\\n\\treturn [func(x) for x in input().split()]\\n(m, n) = cin(int)\\nprint(floor(m * n / 2))\\n\",\n \"string = input()\\nstring1 = string.split(' ')\\nresult = int(string1[0]) * int(string1[1]) // 2\\nprint(result)\\n\",\n \"(M, N) = input('').split()\\nM = int(M)\\nN = int(N)\\narea = M * N\\na = 2\\nb = 1\\ncount = area // 2\\nprint(count)\\n\",\n \"inp = input().split(' ')\\nm = int(inp[0])\\nn = int(inp[1])\\nif m % 2 == 0:\\n\\tprint(m // 2 * n)\\nelif n % 2 == 0:\\n\\tprint(n // 2 * m)\\nelse:\\n\\tprint((m - 1) // 2 * n + (n - 1) // 2)\\n\",\n \"(a, b) = input().split(' ')\\n(a, b) = (int(a), int(b))\\nsol = int(a * b / 2)\\nprint(sol)\\n\",\n \"M_N = input().split()\\nM = int(M_N[0])\\nN = int(M_N[1])\\nvivod = M * N // 2\\nprint(vivod)\\n\",\n \"from math import floor\\n\\ndef fun():\\n\\tstr = input().strip().split()\\n\\t(n, m) = (int(str[0]), int(str[1]))\\n\\ta = n * m\\n\\treturn int(floor(a / 2))\\nprint(fun())\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nsquares = m * n\\nminVal = math.floor(m * n / 2)\\nprint(minVal)\\n\",\n \"bord = input()\\ndomino = 2\\nb = bord.split(' ')\\n(M, N) = (int(b[0]), int(b[1]))\\nif M * N % 2 == 0:\\n\\tans1 = M * N / domino\\nelse:\\n\\tans1 = (M * N - 1) / domino\\nprint(int(ans1))\\n\",\n \"inp = input().split(' ')\\nM = int(inp[0])\\nN = int(inp[1])\\n\\ndef calculate_result(M, N):\\n\\tif M % 2 == 0:\\n\\t\\treturn M / 2 * N\\n\\tif N % 2 == 0:\\n\\t\\treturn N / 2 * M\\n\\telse:\\n\\t\\treturn (M * N - 1) / 2\\nres = calculate_result(M, N)\\nprint(int(res))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m * n % 2 == 0:\\n\\tx = int(m * n / 2)\\n\\tprint(x)\\nelse:\\n\\tx = int(m * n // 2)\\n\\tprint(x)\\n\",\n \"import math\\n(m, n) = map(lambda x: int(x), input().split())\\nk = m * n\\nc = k / 2\\nif k % 2 > 0:\\n\\tprint(math.floor(c))\\nelse:\\n\\tprint(int(c))\\n\",\n \"(x, y) = map(int, input().strip().split())\\nboard_size = x * y\\nresult = 0\\nif board_size % 2 == 0:\\n\\tresult = board_size // 2\\nelse:\\n\\tresult = (board_size - 1) // 2\\nprint(result)\\n\",\n \"n = input().split(' ')\\np = int(n[0]) * int(n[1])\\nif p % 2 == 0:\\n\\tprint(int(p / 2))\\nelse:\\n\\tprint(int(p / 2 - 0.5))\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nans = 0\\nif n % 2 == 0:\\n\\tans = n / 2 * m\\nelif m % 2 == 0:\\n\\tans = m / 2 * n\\nelse:\\n\\tans = n // 2 * m\\n\\tans += m // 2\\nprint(int(ans))\\n\",\n \"board_dimensions = input().split(' ')\\nnum_dominos = int(board_dimensions[0]) * int(board_dimensions[1]) // 2\\nprint(num_dominos)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nx = m * n\\nans = x // 2\\nprint(ans)\\n\",\n \"import math\\nx = input()\\n(m, n) = (int(x.split()[0]), int(x.split()[1]))\\nif m % 2 != 0 and n % 2 != 0:\\n\\ta = math.floor(m / 2)\\n\\tb = math.floor(n / 2)\\n\\tc = b * m + a\\n\\tprint(int(c))\\nelif m % 2 == 0 and n % 2 != 0:\\n\\ta = m / 2\\n\\tb = math.floor(n / 2)\\n\\tc = m * b + a\\n\\tprint(int(c))\\nelif m % 2 != 0 and n % 2 == 0:\\n\\ta = n / 2\\n\\tc = m * a\\n\\tprint(int(c))\\nelse:\\n\\ta = m / 2\\n\\tc = a * n\\n\\tprint(int(c))\\n\",\n \"m_n = [int(x) for x in input().split()]\\nprint(m_n[0] * m_n[1] // 2)\\n\",\n \"a = input()\\na = a.split(' ')\\nf = int(a[0]) * int(a[1])\\nprint(f // 2)\\n\",\n \"a = input().split()\\nb = int(a[0]) * int(a[1])\\nc = 0\\nz = 0\\nwhile b > 1:\\n\\tif b % 2 == 0:\\n\\t\\tb = b - 2\\n\\t\\tc += 1\\n\\telse:\\n\\t\\tb = b - 2\\n\\t\\tz += 1\\nprint(c + z)\\n\",\n \"n = input().split()\\n(m, n) = (int(n[0]), int(n[1]))\\nif m == n == 1:\\n\\tprint('0')\\nif m % 2 == 0 and (m != 1 or n != 1):\\n\\tx = m / 2 * n\\n\\tprint(int(x))\\nif m % 2 != 0 and (m != 1 or n != 1):\\n\\tx = m // 2 * n + n // 2\\n\\tprint(int(x))\\n\",\n \"from sys import stdin, stdout\\n(a, b) = stdin.read().split()\\n(a, b) = (int(a), int(b))\\nif a % 2 != 0 and b % 2 != 0:\\n\\tc = (a * b - 1) // 2\\nelse:\\n\\tc = a * b // 2\\nstdout.write(str(c))\\n\",\n \"a = input().split()\\nif int(a[0]) % 2 == 0 or int(a[1]) % 2 == 0:\\n\\tprint(int(int(a[0]) * int(a[1]) / 2))\\nelse:\\n\\tprint(int((int(a[0]) * int(a[1]) - 1) / 2))\\n\",\n \"import sys\\nnums = sys.stdin.readline().split(' ')\\nm = int(nums[0])\\nn = int(nums[1])\\nprint(m * n // 2)\\n\",\n \"def check(m, n):\\n\\tcounter = 0\\n\\twhile m >= 2:\\n\\t\\tcounter += n\\n\\t\\tm -= 2\\n\\tif m == 1:\\n\\t\\twhile n > 1:\\n\\t\\t\\tcounter += 1\\n\\t\\t\\tn -= 2\\n\\treturn counter\\n(m, n) = [int(elem) for elem in input().split()]\\nprint(check(m, n))\\n\",\n \"(m, n) = map(lambda x: int(x), input().split())\\nif m < n:\\n\\t(m, n) = (n, m)\\ntotal = 0\\ntotal += m // 2 * n\\nif m % 2 == 1:\\n\\t(m, n) = (n, m % 2)\\n\\ttotal += m // 2\\nprint(total)\\n\",\n \"data = input()\\ndataList = data.split(' ')\\nm = int(dataList[0])\\nn = int(dataList[1])\\narea = m * n\\nmax_domino = area // 2\\nprint(max_domino)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\ndies_size = 2 * 1\\ndies_needed = m * n / dies_size\\nprint(math.floor(dies_needed))\\n\",\n \"r = 2\\nc = 1\\nx = input().split()\\nm = int(x[0])\\nn = int(x[1])\\nj = int(m / r)\\nk = int(n / c)\\nl = m - r * j\\nh = n - c * k\\nresult = k * j\\nif l > 0 and l >= c and (r <= n):\\n\\ttemp_m = l\\n\\ttemp_n = n\\n\\ttemp_c = r\\n\\ttemp_r = c\\n\\ttemp_j = int(temp_m / temp_r)\\n\\ttemp_k = int(temp_n / temp_c)\\n\\tresult += temp_j * temp_k\\nelif h > 0 and h >= r and (c <= m):\\n\\ttemp_m = m\\n\\ttemp_n = h\\n\\ttemp_c = r\\n\\ttemp_r = c\\n\\ttemp_j = int(temp_m / temp_r)\\n\\ttemp_k = int(temp_n / temp_c)\\n\\tresult += temp_j * temp_k\\nprint(int(result))\\n\",\n \"import sys\\nm_and_n = input()\\nm_and_n = m_and_n.split()\\nm = int(m_and_n[0])\\nn = int(m_and_n[1])\\nproduct = int(m) * int(n)\\nwhile True:\\n\\tif product % 2 == 0:\\n\\t\\tprint(int(product / 2))\\n\\t\\tbreak\\n\\tproduct -= 1\\n\\tif product == 0:\\n\\t\\tprint(0)\\n\\t\\tbreak\\n\",\n \"input = input().split()\\nsize = int(input[0]) * int(input[1])\\nwhile True:\\n\\tif size % 2 == 0:\\n\\t\\tbreak\\n\\telse:\\n\\t\\tsize -= 1\\nprint(size // 2)\\n\",\n \"nk = input().split()\\nn = int(nk[0])\\nk = int(nk[1])\\nprint(n * k // 2)\\n\",\n \"n = input()\\nb = n.split()\\nc = int(b[0]) * int(b[1])\\nf = c // 2\\nprint(f)\\n\",\n \"line = input()\\narr = line.split()\\nsum = 0\\na = int(arr[0])\\nb = int(arr[1])\\ntemp1 = a // 2\\nsum = temp1 * b\\ntemp2 = a % 2\\nif temp2 == 1:\\n\\tsum += b // 2\\nprint(int(sum))\\n\",\n \"(M, N) = map(int, input().split())\\nprint(M * N // (2 * 1))\\n\",\n \"while True:\\n\\ttry:\\n\\t\\tl = input().split()\\n\\t\\tM = int(l[0])\\n\\t\\tN = int(l[1])\\n\\t\\ts = M * N\\n\\t\\ta = s // 2\\n\\t\\tprint(a)\\n\\texcept EOFError:\\n\\t\\tbreak\\n\",\n \"(M, N) = input().split()\\nsquare = int(M) * int(N)\\ntemp = int(square / 2)\\nprint(temp)\\n\",\n \"import math\\n(m, n) = [int(x) for x in input().split()]\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nc = int(n / 2)\\nd = int(m / 2)\\nif n % 2 == 0:\\n\\tprint(c * m)\\nelse:\\n\\tprint(c * m + d)\\n\",\n \"content = input().split()\\nm = int(content[0])\\nn = int(content[1])\\nif m % 2 == 0:\\n\\tx = int(m / 2) * n\\nelse:\\n\\tx = int(m / 2) * n + int(n / 2)\\nprint(x)\\n\",\n \"a = input().split(' ')\\nploshad = int(a[0]) * int(a[1])\\ncheck = ploshad // 2\\nprint(str(check))\\n\",\n \"a = input().split()\\nM = int(max(a))\\nN = int(min(a))\\nnum = int(M / 2) * N + int(N / 2) * (M % 2)\\nprint(num)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nproduct = n * m\\nprint(product // 2)\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nno = math.floor(m * n / 2)\\nprint(no)\\n\",\n \"a = input()\\nb = a.split(' ')\\nc = []\\nfor i in b:\\n\\tc.append(int(i))\\nz = c[0] * c[1] // 2\\nprint(z)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nar = a * b\\nbr = 2\\nc = 0\\nwhile br <= ar:\\n\\tc += 1\\n\\tbr = br + 2\\nprint(c)\\n\",\n \"a = list(input().split(' '))\\nm = int(a[0])\\nn = int(a[1])\\nk = m * n\\nz = k // 2\\nprint(z)\\n\",\n \"(m, n) = (int(v) for v in input().split())\\nprint(m * n // 2)\\n\",\n \"nums = input()\\nnums = nums.strip().split()\\nm = int(nums[0])\\nn = int(nums[1])\\ntotal = m * n\\nprint(total // 2)\\n\",\n \"ip = input().split()\\n(m, n) = (int(ip[0]), int(ip[1]))\\nif m == 1:\\n\\tprint(n // 2)\\nelif n == 1:\\n\\tprint(m // 2)\\nelif m % 2 == 0 and n % 2 == 0:\\n\\tprint(m * n // 2)\\nelif n % 2 == 0:\\n\\tprint(m * n // 2)\\nelse:\\n\\tprint(m * (n - 1) // 2 + m // 2)\\n\",\n \"p = input().split()\\nprint(int(p[0]) * int(p[1]) // 2)\\n\",\n \"from sys import stdin, stdout\\n(m, n) = map(int, stdin.readline().split())\\nstdout.write(f'{m * n // 2}\\\\n')\\n\",\n \"import math\\nar = str.split(input())\\nM = int(ar[0])\\nN = int(ar[1])\\nif 1 <= M <= N <= 16:\\n\\tif M % 2 == 1:\\n\\t\\tx = math.floor(M / 2) * N\\n\\t\\ty = math.floor(N / 2)\\n\\t\\tprint(x + y)\\n\\tif M % 2 == 0:\\n\\t\\tx = M / 2 * N\\n\\t\\tprint(int(x))\\n\",\n \"(x, y) = map(int, input().split())\\na = x * y\\nprint(int(a / 2))\\n\",\n \"(M, N) = input().split()\\nout = int(M) * int(N) // 2\\nprint(out)\\n\",\n \"import sys\\nimport collections\\nimport math\\nimport functools\\nimport itertools\\nimport bisect\\nimport operator\\nimport heapq\\nimport random\\ntrue = True\\nfalse = False\\nnull = None\\ntcid = 0\\n\\ndef ceil(a, b):\\n\\tans = a // b\\n\\tif a % b != 0:\\n\\t\\tans += 1\\n\\treturn ans\\n\\ndef perr(*args, **kwargs):\\n\\tprint(*args, file=sys.stderr, **kwargs)\\n\\ndef line():\\n\\tln = sys.stdin.readline().strip()\\n\\tif ln == '':\\n\\t\\tsys.exit()\\n\\treturn ln\\n\\ndef lines(n):\\n\\treturn [line() for i in range(n)]\\n\\ndef split(ln=None):\\n\\treturn (ln or line()).split()\\n\\ndef parse(*parsers):\\n\\treturn list(map(lambda p, w: p(w), parsers, split()))\\n\\ndef nums(o=None):\\n\\tif o is not None:\\n\\t\\tif isinstance(o, int):\\n\\t\\t\\to = lines(o)\\n\\t\\telif isinstance(o, str):\\n\\t\\t\\to = split(o)\\n\\treturn list(map(int, o or split()))\\n\\ndef num():\\n\\treturn int(line())\\n\\ndef solve(tcid=1):\\n\\t(m, n) = nums()\\n\\tprint(m * n // 2)\\nwhile true:\\n\\ttcid += 1\\n\\tsolve(tcid)\\n\",\n \"line = [int(x) for x in input('').strip().split(' ')]\\nm = line[0]\\nn = line[1]\\nprint(m * n // 2)\\n\",\n \"print(eval('*'.join(input().split())) // 2)\\n\",\n \"a = input().split(' ')\\nb = int(a[0])\\nc = int(a[1])\\nf = b * c / 2\\nprint(int(f))\\n\",\n \"lst = list(map(int, input().split()))\\n(n, m) = (lst[0], lst[1])\\nprod = n * m\\nprint(prod // 2)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nif n == 1 or m == 1:\\n\\tif n == 1:\\n\\t\\tprint(m // 2)\\n\\telif m == 1:\\n\\t\\tprint(n // 2)\\nelif m % 2 != 0 and n % 2 != 0:\\n\\tif m > n:\\n\\t\\te = m\\n\\t\\tr = n\\n\\telse:\\n\\t\\te = n\\n\\t\\tr = m\\n\\tu = e - 1\\n\\tb = u * r // 2\\n\\tv = r // 2\\n\\tprint(b + v)\\nelse:\\n\\tfuck = m * n // 2\\n\\tprint(fuck)\\n\",\n \"(board_width, board_height) = map(int, input().split())\\nif board_width % 2 == 0:\\n\\tno_domino = board_width / 2 * board_height\\nelse:\\n\\tno_domino1 = board_width // 2 * board_height\\n\\tremaining_places = board_width % 2 * board_height\\n\\tno_domino2 = remaining_places // 2\\n\\tno_domino = no_domino1 + no_domino2\\nprint(int(no_domino))\\n\",\n \"ln = [int(i) for i in input().split(' ')]\\nprint(max([ln[0] // 2 * ln[1] + ln[0] % 2 * (ln[1] // 2), ln[1] // 2 * ln[0] + ln[1] % 2 * (ln[0] // 2)]))\\n\",\n \"import sys\\ndbg = False\\nif dbg:\\n\\tsys.stdin = open('input.txt')\\ndin = lambda : map(int, input().split())\\n(M, N) = din()\\nif M * N % 2 == 0:\\n\\tprint(M * N // 2)\\nelse:\\n\\tprint((M * N - 1) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nboard = m * n\\nfit = board // 2\\nprint(fit)\\n\",\n \"import sys\\nf = sys.stdin\\n(n, m) = map(int, f.readline().split())\\nres = n * m // 2\\nprint(res)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\ntot = m * n\\np = 2 * 1\\nprint(tot // p)\\n\",\n \"import math\\n(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nprint(math.floor(m * n * 0.5))\\n\",\n \"R = lambda : map(int, input().split())\\n(n, m) = R()\\nans = int(n * m / 2)\\nprint(ans)\\n\",\n \"(M, N) = list(map(int, input().rstrip().split()))\\ndom = M * N // 2\\nprint(dom)\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\nn = M * N // 2\\nprint(n)\\n\",\n \"(m, n) = map(int, input().split())\\nk = m * n\\nd = k // 2\\nd = int(d)\\nprint(d)\\n\",\n \"a = map(int, input().split())\\na = list(a)\\n(n, m) = (a[0], a[1])\\nc = n * m\\nprint(int(c / 2))\\n\",\n \"def input_int():\\n\\treturn int(input())\\n\\ndef input_int_list():\\n\\treturn list(map(int, input().split()))\\n\\ndef input_input_map():\\n\\treturn map(int, input().split())\\n\\ndef run():\\n\\t(m, n) = input_input_map()\\n\\tprint(m * n // 2)\\nrun()\\n\",\n \"val = input()\\nval = val.split()\\nx = int(val[0])\\ny = int(val[1])\\nn = 0\\nnew = 0\\nif y % 2 == 0:\\n\\tif x % 2 == 0:\\n\\t\\tx = int(x / 2)\\n\\t\\tn = y * x\\n\\telse:\\n\\t\\tx = (x - 1) / 2\\n\\t\\tn = y * int(x)\\n\\t\\tn = n + int(y / 2)\\nelif x % 2 == 0:\\n\\tx = int(x / 2)\\n\\tn = y * x\\nelse:\\n\\tnew = int((x - 1) / 2)\\n\\tn = (y - 1) * new\\n\\tn = n + int(y / 2) + int(x / 2)\\nprint(n)\\n\",\n \"import sys\\n\\ndef domino_square(n, m):\\n\\tc = n * m\\n\\td = 0\\n\\tif c % 2 == 0:\\n\\t\\td = c // 2\\n\\telse:\\n\\t\\td = (c - 1) // 2\\n\\tprint(d)\\nfor line in sys.stdin:\\n\\tparts = line.split(' ')\\n\\tdomino_square(int(parts[0]), int(parts[1]))\\n\",\n \"tmp = input().split(' ')\\nm = int(tmp[0])\\nn = int(tmp[1])\\nprint(m * n // 2)\\n\",\n \"(x, y) = list(map(int, input().split()))\\nprint(x * y // 2)\\n\",\n \"inp = input()\\nsize = list(map(int, inp.split()))\\nwidth = size[0]\\nheight = size[1]\\nprint(int(width * height / 2))\\n\",\n \"(m, n) = input().split()\\nx = 0\\nx = int(m) // 2 * int(n)\\ny = 0\\nif int(m) % 2 == 1:\\n\\ty = int(n) // 2\\nprint(x + y)\\n\",\n \"def crear_archivo():\\n\\tarchivo = open('archivo_de_práctica', 'w')\\n\\tarchivo.close\\n\\ndef escribir_archivo():\\n\\tarchivo = open('agenda.nro1', 'a')\\n\\tcadena = input('introducir nombre de archivo')\\n\\tarchivo.write(cadena)\\n\\tarchivo.close\\nentrada = input()\\nlista = list()\\nancho = int(entrada[:entrada.find(' ')])\\nlargo = int(entrada[entrada.find(' ') + 1:])\\narea = ancho * largo\\nprint(area // 2)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ntotal_number = m * n / 2\\nprint(int(total_number))\\n\",\n \"y = input().split()\\na = int(y[0])\\nb = int(y[1])\\nc = a * b\\nx = 0\\nfor i in range(2, c + 1, 2):\\n\\tx = x + 1\\nprint(x)\\n\",\n \"inputs = list(map(int, input().rstrip().split()))\\nsize = int(inputs[0] * inputs[1])\\nnumberoftiles = 0\\nif size >= 2:\\n\\tnumberoftiles = int(size / 2)\\nprint(numberoftiles)\\n\",\n \"p = list(map(int, input().split()))\\nprint(int(p[0] * p[1] / 2))\\n\",\n \"import sys\\nimport math\\nimport bisect\\nimport re\\n\\ndef main():\\n\\t(n, m) = map(int, input().split())\\n\\tprint(n * m // 2)\\nmain()\\n\",\n \"inpt = [int(x) for x in input().split()]\\nans = int(inpt[0] * inpt[1] / 2)\\nprint(ans)\\n\",\n \"nums = input()\\nnums = nums.split()\\n(m, n) = (int(nums[0]), int(nums[1]))\\ncount = m * n / 2\\nprint(int(count))\\n\",\n \"m = input()\\nn = m.split(' ')\\nprint(str(int(n[0]) * int(n[1]) // 2))\\n\",\n \"(x, y) = map(int, input().split())\\np = min(x, y) // 1\\nq = max(x, y) // 2\\nz = p * q\\ns = abs(p * q * 2 - x * y) // 2\\nprint(s + z)\\n\",\n \"inp = input().split(' ')\\nM = int(inp[0])\\nN = int(inp[1])\\nM1 = M - M % 2\\nN1 = N - N % 2\\nC = M1 * N1 / 2\\nresult = 0\\nif M % 2 == 1 or N % 2 == 1:\\n\\tif M % 2 == 1 and N % 2 == 1:\\n\\t\\tresult = C + M1 / 2 + N1 / 2\\n\\telif M % 2 == 1 and N % 2 == 0:\\n\\t\\tresult = C + N / 2\\n\\telse:\\n\\t\\tresult = C + M / 2\\nelse:\\n\\tresult = C\\nprint(str(int(result)))\\n\",\n \"(a, b) = map(int, input().split())\\nar = 2\\nc = 0\\nt = 0\\nwhile t < a * b - 1:\\n\\tc += 1\\n\\tt = c * ar\\nprint(c)\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nmsr1 = int(m / 2)\\nmsr = msr1 * n\\nrem = m % 2\\nnsr = rem * n\\nnsr1 = int(nsr / 2)\\nr = msr + nsr1\\nprint(r)\\n\",\n \"a = [int(x) for x in input().split()]\\nprint(a[0] * a[1] // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nlist = [m, n]\\na = max(list)\\nb = min(list)\\nif a % 2 == 0:\\n\\tnum = b * (a // 2)\\nelse:\\n\\tnum = b * (a // 2) + b // 2\\nprint(num)\\n\",\n \"t = input()\\na = t.split(' ')\\nm = int(a[0])\\nn = int(a[1])\\nif 1 <= m <= n <= 16:\\n\\tp = int(m * n / 2)\\n\\tprint(p)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\narea = m * n\\nif area % 2 != 0:\\n\\tprint(area // 2)\\nelse:\\n\\tprint(area // 2)\\n\",\n \"(n, k) = map(int, input().split())\\nv = n * k // 2\\nprint(v)\\n\",\n \"(l, b) = list(map(int, input().split()))\\nprint(l * b // 2)\\n\",\n \"vals = input()\\nm = int(vals.split()[0])\\nn = int(vals.split()[1])\\nprint(int(m * n / 2))\\n\",\n \"_boardSize = [int(x) for x in input().split(' ')]\\nboardSize = _boardSize[0] * _boardSize[1]\\nif boardSize % 2 == 1:\\n\\tprint((boardSize - 1) // 2)\\nelse:\\n\\tprint(boardSize // 2)\\n\",\n \"(n, m) = [int(i) for i in input().split()]\\nans = int(n * m / 2)\\nprint(ans)\\n\",\n \"def main():\\n\\t(m, n) = [int(x) for x in input().strip().split()]\\n\\tif m % 2 == 0 and n % 2 == 0:\\n\\t\\tprint(int(m * n / 2))\\n\\telif m % 2 == 0 and n % 2 != 0:\\n\\t\\tprint(int(m * n / 2))\\n\\telif n % 2 == 0 and m % 2 != 0:\\n\\t\\tprint(int(m * n / 2))\\n\\telse:\\n\\t\\tprint(int((m - 1) / 2 + m * (n - 1) / 2))\\nmain()\\n\",\n \"l = []\\n(a, b) = map(int, input().split())\\nl.append(a)\\nl.append(b)\\nm = a * b\\nn = 2 * 1\\ne = m // n\\nprint(e)\\n\",\n \"def f(a, b):\\n\\tr = a // 2 * b\\n\\tif a % 2 == 1:\\n\\t\\tr += b // 2\\n\\treturn r\\ns = input().split(' ')\\n(m, n) = [int(s[i]) for i in range(0, 2)]\\nprint(max(f(m, n), f(n, m)))\\n\",\n \"user = input().split()\\nprod = int(user[0]) * int(user[1])\\nrem = prod // 2\\nprint(rem)\\n\",\n \"import math\\n\\ndef DominoPilling(m, n):\\n\\treturn math.floor(m * n / 2)\\n(m, n) = input().split()\\nprint(DominoPilling(int(m), int(n)))\\n\",\n \"n = list(map(int, input().strip().split(' ')))\\nif n[1] * n[0] % 2 == 0:\\n\\tprint(n[1] * n[0] // 2)\\nelse:\\n\\tprint((n[0] * n[1] - 1) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nz = m * n\\nd = z // 2\\nprint(d)\\n\",\n \"(m, n) = map(int, input().split(' '))\\ntotal = m // 2 * n\\nif m % 2 == 1:\\n\\ttotal += n // 2\\nprint(total)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nif 1 <= a <= b <= 16:\\n\\td = a * b\\n\\te = int(d / 2)\\n\\tprint(e)\\n\",\n \"(a, b) = map(int, input().strip().split())\\nc = a * b\\nprint(c // 2)\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nif M % 2 == 0 or N % 2 == 0:\\n\\tm = M * N / 2\\nelse:\\n\\tm = (M * N - 1) / 2\\nf = int(m)\\nprint(f)\\n\",\n \"(n, d) = map(int, input().split())\\nprint(n * d // 2)\\n\",\n \"while True:\\n\\ttry:\\n\\t\\ta = []\\n\\t\\ta = input().split(' ')\\n\\t\\tfor i in range(len(a)):\\n\\t\\t\\ta[i] = int(a[i])\\n\\t\\tif a[0] * a[1] & 1:\\n\\t\\t\\tcon = (a[0] * a[1] - 1) / 2\\n\\t\\telse:\\n\\t\\t\\tcon = a[0] * a[1] / 2\\n\\t\\tprint(int(con))\\n\\texcept:\\n\\t\\tbreak\\n\",\n \"import math\\ns = input().split()\\nprint(math.floor(int(s[0]) * int(s[1]) / 2))\\n\",\n \"def DominoPiling():\\n\\tinputs = input().split()\\n\\tmn = int(inputs[0]) * int(inputs[1])\\n\\treturn int(mn / 2)\\nprint(DominoPiling())\\n\",\n \"(m, n) = [int(_) for _ in input().split()]\\nprint(m // 2 * n + m % 2 * n // 2)\\n\",\n \"(n, m) = map(int, input().split())\\nans = 0\\nrandint = 0\\nif m >= 1 and m <= 16 and (n <= 16) and (n >= 1):\\n\\tif n % 2 == 1 and m % 2 == 1:\\n\\t\\trandint = n * m\\n\\t\\tans = randint / 2 - 0.5\\n\\t\\tprint(int(ans))\\n\\telse:\\n\\t\\trandint = n * m\\n\\t\\tans = randint / 2\\n\\t\\tprint(int(ans))\\n\",\n \"(m, n) = [int(i) for i in input().split(' ')]\\nr = m * n // 2\\nprint(r)\\n\",\n \"count = 0\\n(n, k) = map(int, input().split())\\nt = n * k\\nif t % 2 == 0:\\n\\tcount = t // 2\\nelse:\\n\\tt -= 1\\n\\tcount = t // 2\\nprint(count)\\n\",\n \"my_input = input()\\n(a, b) = my_input.split()\\na = int(a)\\nb = int(b)\\n\\ndef dominos(m, n):\\n\\treturn print(m * n // 2)\\ndominos(a, b)\\n\",\n \"from sys import stdin\\ninput_list = [int(i) for i in stdin.readline().split(' ')]\\n(m, n) = input_list\\nprint(int(m * n / 2))\\n\",\n \"size = input().split(' ')\\nlimit = int(size[0]) * int(size[1])\\nanswer = int(limit / 2)\\nprint(answer)\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\nh = []\\nfor i in list_we_use:\\n\\th.append(int(i))\\nn = h[0] * h[1]\\nprint(n // 2)\\n\",\n \"import sys\\ndata = sys.stdin.readlines()\\nm = int(data[0].split()[0])\\nn = int(data[0].split()[1])\\na = m // 2 * n\\nif m % 2 != 0:\\n\\ta += n // 2\\nprint(a)\\n\",\n \"n = input().split()\\na = int(n[0])\\nb = int(n[1])\\nanswer = int(a * b / 2)\\nprint(answer)\\n\",\n \"(m, n) = list(map(int, input().strip().split()))\\nans = m * n // 2\\nprint(ans)\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nif N == 1 and M == 1:\\n\\tprint(0)\\nelse:\\n\\tprint(N * M // 2)\\n\",\n \"def domino(n, m):\\n\\tarea = n * m\\n\\tcount = area // 2\\n\\treturn count\\n(n, m) = map(int, input().split())\\nprint(domino(n, m))\\n\",\n \"from sys import stdin\\n\\ndef main():\\n\\t(a, b) = [int(c) for c in stdin.readline().strip().split()]\\n\\tprint(a * b // 2)\\nmain()\\n\",\n \"digit = input().split()\\nfor i in range(2):\\n\\tdigit[i] = int(digit[i])\\ndiv = digit[0] * digit[1] / 2\\nprint(int(div))\\n\",\n \"mn = input().split()\\nm = int(mn[0])\\nn = int(mn[1])\\nif n * m % 2 == 0:\\n\\tprint(n * m // 2)\\nelse:\\n\\tprint((n * m - 1) // 2)\\n\",\n \"i = lambda : map(int, input().split())\\n(m, n) = i()\\nprint(int(m * n / 2))\\n\",\n \"def getdcount(m, n):\\n\\tc = m // 2 * n\\n\\tif m % 2:\\n\\t\\tc += n // 2\\n\\treturn c\\n(m, n) = tuple(map(int, input().split()))\\nprint(getdcount(m, n))\\n\",\n \"f = list(map(int, input().split()))\\nprint(int(f[0] * f[1] / 2))\\n\",\n \"nums = list((int(i) for i in input().split()))\\nresult = 0\\nm2 = nums[0]\\nwhile nums[1] > 1:\\n\\tm1 = nums[0]\\n\\twhile m1 > 0:\\n\\t\\tresult += 1\\n\\t\\tm1 -= 1\\n\\tnums[1] -= 2\\nif nums[1] == 1:\\n\\twhile m2 > 1:\\n\\t\\tresult += 1\\n\\t\\tm2 -= 2\\nprint(result)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nt = 2 * 1\\na = m * n\\nprint(a // t)\\n\",\n \"import math\\nx = input()\\nwymiar = []\\nfor i in x.split(' '):\\n\\twymiar.append(int(i))\\npole = wymiar[0] * wymiar[-1]\\ny = pole / 2\\nif pole % 2 == 0:\\n\\tprint(int(y))\\nelse:\\n\\tprint(int(math.floor(y)))\\n\",\n \"a = input()\\na = a.split()\\nz = int(a[0])\\nt = int(a[1])\\np = z * t\\nif p % 2 == 0:\\n\\tm = int(p / 2)\\nelse:\\n\\tm = int((p - 1) / 2)\\nprint(m)\\n\",\n \"def dominoshka():\\n\\tinput_ = [int(i) for i in input().split()]\\n\\tarea = input_[0] * input_[1]\\n\\tprint(area // 2)\\ndominoshka()\\n\",\n \"inp = input()\\ndata = inp.split()\\narea = int(data[0]) * int(data[1])\\nprint(area // 2)\\n\",\n \"(a, b) = map(int, input().split())\\ns = a * b\\npiece = s // 2\\nprint(piece)\\n\",\n \"l = input()\\nl = l.split()\\nm = int(l[0])\\nn = int(l[1])\\nr = m * n // 2\\nprint(r)\\n\",\n \"class domino:\\n\\n\\tdef __init__(self, m, n):\\n\\t\\tself.m = m\\n\\t\\tself.n = n\\n\\t\\tself.count = 0\\n\\n\\tdef compute(self):\\n\\t\\tarea = self.m * self.n\\n\\t\\trem = area % 2\\n\\t\\tif rem == 0:\\n\\t\\t\\tself.count = int(area / 2)\\n\\t\\telse:\\n\\t\\t\\tself.count = int(area / 2)\\n\\n\\tdef output(self):\\n\\t\\tprint(self.count)\\n\\n\\tdef execute(self):\\n\\t\\tself.compute()\\n\\t\\tself.output()\\n\\ndef main():\\n\\tstr1 = input()\\n\\tlist1 = str1.split()\\n\\ta = int(list1[0])\\n\\tb = int(list1[1])\\n\\td1 = domino(a, b)\\n\\td1.execute()\\nmain()\\n\",\n \"(n, m) = map(int, input().split())\\nprint(max(n, m) * min(n, m) // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\narea = m * n\\ncount = area // 2\\nprint(count)\\n\",\n \"def ans() -> int:\\n\\t(x, y) = [int(x) for x in input().split()]\\n\\tarea = x * y\\n\\tif area == 1:\\n\\t\\treturn 0\\n\\tif area % 2 == 0:\\n\\t\\treturn area / 2\\n\\telse:\\n\\t\\treturn (area - 1) / 2\\nprint(int(ans()))\\n\",\n \"(m, n) = list(map(lambda x: int(x), input().split(' ')))\\nif m * n > 1:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(0)\\n\",\n \"m = list(map(int, input().split()))\\narea = m[0] * m[1]\\nrequired = int(area / 2)\\nprint(required)\\n\",\n \"inputList = input().split()\\nfor i in range(len(inputList)):\\n\\tinputList[i] = int(inputList[i])\\nn = inputList[0]\\nm = inputList[1]\\nans = n * (m // 2)\\nif m % 2 != 0:\\n\\tans += n // 2\\nprint(str(ans))\\n\",\n \"w = input().split()\\n(m, n) = (int(w[0]), int(w[1]))\\nprint(int(m * n / 2))\\n\",\n \"def domino(m, n):\\n\\tdom_len = 2\\n\\tdom_width = 1\\n\\tarea = m * n\\n\\tnumber_need = area // (dom_len * dom_width)\\n\\tprint(number_need)\\ndomino(*map(int, input().split()))\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nx_dom = 2\\ny_dom = 1\\nprint(int(int(m * n) / (x_dom * y_dom)))\\n\",\n \"try:\\n\\t(n, m) = map(int, input().split())\\n\\tcnt = 0\\n\\tif n % 2 != 0 and m % 2 != 0:\\n\\t\\tcnt = (n - 1) * m / 2 + (m - 1) / 2\\n\\telse:\\n\\t\\tcnt = n * m / 2\\n\\tprint(int(cnt))\\nexcept ValueError:\\n\\tprint('Unexpected value')\\n\",\n \"m = input().split()\\nif 1 <= int(m[0]) <= int(m[1]) <= 16:\\n\\tres = int(m[0]) * int(m[1]) * 0.5\\n\\tprint(int(res))\\n\",\n \"from sys import stdin\\n(M, N) = map(int, stdin.readline().split())\\nprint(M * N // 2)\\n\",\n \"s = input().strip()\\nls = s.split(' ')\\nwidth = int(ls[0])\\nheight = int(ls[1])\\nmax_num_of_dominos = 0\\nif 1 <= width <= height <= 16:\\n\\tboard_size = width * height\\n\\tmax_num_of_dominos = int(board_size / 2)\\nprint(max_num_of_dominos)\\n\",\n \"l = list(map(int, input().split(' ')))\\nn = int(l[0])\\nm = int(l[1])\\na = n\\nb = m\\nt = 0\\nwhile b > 0:\\n\\tsum = a * b\\n\\tif sum % 2 == 0:\\n\\t\\tt = int(sum / 2)\\n\\t\\tt = t + int((m - b) * a / 2)\\n\\t\\tbreak\\n\\telse:\\n\\t\\tb -= 1\\nprint(t)\\n\",\n \"x = input().split()\\nm = int(x[0])\\nn = int(x[1])\\nif m * n % 2 == 0:\\n\\tk = m * n / 2\\n\\tprint(int(k))\\nelif m * n % 2 == 1:\\n\\tl = m * n / 2 - 0.5\\n\\tprint(int(l))\\n\",\n \"import math\\n(n, k) = (input().split(), 1)\\nfor i in n:\\n\\tk = k * int(i)\\nprint(math.floor(k / 2))\\n\",\n \"mn = list(map(int, input().split()))\\nm = mn[0]\\nn = mn[1]\\ntileArea = 2 * 1\\nboardArea = m * n\\nprint(boardArea // tileArea)\\n\",\n \"(n, k) = input('').split()\\nx = int(n) * int(k)\\nz = int(x / 2)\\nprint(z)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nk = M * N / 2\\nprint(math.floor(k))\\n\",\n \"q = input().split()\\nif int(q[0]) * int(q[1]) % 2 > 0:\\n\\tprint((int(q[0]) * int(q[1]) - 1) // 2)\\nelse:\\n\\tprint(int(q[0]) * int(q[1]) // 2)\\n\",\n \"import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, copy, functools\\n\\ndef I():\\n\\treturn int(sys.stdin.readline())\\n\\ndef LI():\\n\\treturn [int(x) for x in sys.stdin.readline().split()]\\n\\ndef main():\\n\\t(n, m) = map(int, input().split())\\n\\treturn n * m // 2\\nprint(main())\\n\",\n \"print([int(n * m / 2) for (n, m) in [map(int, input().rstrip().split())]][0])\\n\",\n \"def count(char1, char2):\\n\\treturn char1 // 2 * char2\\n(M, N) = map(int, input().split())\\nif M % 2 == 0:\\n\\tprint(int(count(M, N)))\\nelif N % 2 == 0:\\n\\tprint(int(count(N, M)))\\nelse:\\n\\tprint(int(count(M - 1, N) + N / 2))\\n\",\n \"import math\\nnumbers = [int(i) for i in input().split()]\\nif numbers[0] % 2 == 1 or numbers[1] % 2 == 1:\\n\\ts = math.floor(numbers[0] * numbers[1] / 2)\\nelse:\\n\\ts = int(numbers[0] * numbers[1] / 2)\\nprint(s)\\n\",\n \"import math\\ni = lambda : map(int, input().split())\\n(n, k) = i()\\nprint(math.floor(n * k / 2))\\n\",\n \"def validate_data(m, n):\\n\\tif m <= 0 or n <= 0:\\n\\t\\treturn False\\n\\telif m > n:\\n\\t\\treturn False\\n\\telif m > 16 or n > 16:\\n\\t\\treturn False\\n\\treturn True\\n\\ndef op(m, n):\\n\\tmatrix = [[0] * n for _ in range(m)]\\n\\tcont = 0\\n\\tfor i in range(m):\\n\\t\\tfor j in range(n):\\n\\t\\t\\tif matrix[i][j] == 0:\\n\\t\\t\\t\\tif j + 1 < n and matrix[i][j + 1] == 0:\\n\\t\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\t\\tmatrix[i][j + 1] = 1\\n\\t\\t\\t\\t\\tcont += 1\\n\\t\\t\\t\\telif i + 1 < m and matrix[i + 1][j] == 0:\\n\\t\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\t\\tmatrix[i + 1][j] = 1\\n\\t\\t\\t\\t\\tcont += 1\\n\\tprint(cont)\\n(m, n) = map(int, input().split())\\nif validate_data(m, n) == True:\\n\\top(m, n)\\n\",\n \"(a, b) = list(map(int, input().split()))\\nc = a * b\\nprint(c // 2)\\n\",\n \"(n, k) = map(int, input().split())\\nj = int(n * k / 2)\\nprint(j)\\n\",\n \"import sys\\n(n, k) = input().split()\\nm = int(min(n, k))\\nm1 = int(max(n, k))\\nprint(m // 2 * m1 + m % 2 * (m1 // 2))\\n\",\n \"(a, b) = map(int, input('').split())\\nans = int(a * b / 2)\\nprint(ans)\\n\",\n \"a = [int(i) for i in input().split()]\\nif 1 <= a[0] <= a[1] <= 16:\\n\\tprint(a[0] * a[1] // 2)\\n\",\n \"__author__ = 'Utena'\\nn = list(map(int, input().split()))\\nprint(int(n[0] * n[1] / 2))\\n\",\n \"(M, N) = map(int, input().split())\\nm = M % 2\\nn = N % 2\\nif m * n == 0:\\n\\tnumber = M * N / 2\\nelse:\\n\\tnumber = M * N / 2 - 1 / 2\\nprint(int(number))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nm1 = int(m / 2)\\nm2 = m - m1 * 2\\nn1 = int(n / 2)\\nnum = m1 * n + m2 * n1\\nprint(num)\\n\",\n \"(n, m) = map(int, input().split())\\na = max(n, m)\\nb = min(n, m)\\ncount = 0\\ncount = a * (b // 2)\\ntemp = b % 2\\nif temp == 1:\\n\\tcount += a // 2\\nprint(count)\\n\",\n \"import sys\\n(m, n) = sys.stdin.readline().split()\\n(m, n) = (int(m), int(n))\\nc = m * n // 2\\nsys.stdout.write(str(c) + '\\\\n')\\n\",\n \"tmp = input().split(' ')\\nM = int(tmp[0])\\nN = int(tmp[1])\\nprint(int(M * N / 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m // 2 >= n // 2:\\n\\tprint(m // 2 * n + m % 2 * (n // 2))\\nelse:\\n\\tprint(n // 2 * m + n % 2 * (m // 2))\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nx = math.floor(M / 2)\\nrestM = M - x * 2\\ny = math.floor(N / 2)\\nnumber = x * N + restM * y\\nprint(number)\\n\",\n \"a = input()\\nb = a.split(' ')\\nm = int(b[0])\\nn = int(b[1])\\narea = m * n\\nk = area // 2\\nprint(k)\\n\",\n \"number = input()\\nsplit_number = number.split()\\n(length, width) = (int(split_number[0]), int(split_number[1]))\\ntimes = length * width\\nif times % 2 == 0:\\n\\tprint(int(times / 2))\\nelse:\\n\\tprint(int((times - 1) / 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ni = m * n\\nj = 2 * 1\\ncount = 0\\nwhile j <= i:\\n\\tj += 2 * 1\\n\\tcount += 1\\nprint(count)\\n\",\n \"(i, j) = map(int, input().split())\\nprint(int(i * j / 2))\\n\",\n \"x = input()\\nx = x.split()\\nfirst = int(x[0])\\nsecond = int(x[1])\\nintnum = first * second / 2\\nprint(int(intnum))\\n\",\n \"(a, b) = map(int, input().split())\\nprint(round(a * b // 2))\\n\",\n \"k = input().split(' ')\\nn = int(k[0])\\nm = int(k[1])\\nprint(n * m // 2)\\n\",\n \"string = input()\\ni = 0\\nwhile True:\\n\\tif string[i] == ' ':\\n\\t\\tbreak\\n\\ti += 1\\na = int(string[0:i + 1])\\nb = int(string[i + 1:i + 4])\\nprint(int(a * b // 2))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nimport math\\nnum = math.floor(n * m / 2)\\nprint(num)\\n\",\n \"import math\\ninputs = list(map(int, input().split()))\\nm = int(inputs[0])\\nn = int(inputs[1])\\nDominoPiece = 2 * 1\\nBoard = m * n\\nnum = int(Board / DominoPiece)\\nif num % 2 == 0:\\n\\tprint(num)\\nelse:\\n\\tprint(math.floor(num))\\n\",\n \"l = list(map(int, input().split()))\\nx1 = int(l[0])\\ny1 = int(l[1])\\ntot = x1 * y1\\nans = tot // 2\\nprint(ans)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0 or n % 2 == 0:\\n\\tnum1 = m * n / 2\\n\\tnum1 = int(num1)\\nelse:\\n\\timport math\\n\\tnum1 = math.floor(m * n / 2)\\n\\tnum1 = int(num1)\\nprint(num1)\\n\",\n \"(M, N) = input().split(' ')\\nM = int(M)\\nN = int(N)\\nif M % 2 == 1 and N % 2 == 1:\\n\\tprint(int((M * N - 1) / 2))\\nelse:\\n\\tprint(int(M * N / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nprint(m * n // 2)\\n\",\n \"desk = list(map(int, input().split()))\\no = desk[0] * desk[1] // 2\\nprint(o)\\n\",\n \"n = input()\\n(a, b) = map(int, n.split())\\ntotal = a * b\\nres = total // 2\\nprint(res)\\n\",\n \"import math\\ninp = input()\\ninp = inp.split(' ')\\nM = int(inp[0])\\nN = int(inp[1])\\narea = M * N\\nnumber = area / 2\\nprint(math.floor(number))\\n\",\n \"import sys\\nimport math\\n(n, m) = map(int, input().split(' '))\\nprint(math.floor(m * n / 2))\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\nc = []\\nfor i in list_we_use:\\n\\tc.append(int(i))\\nz = c[0] * c[1] / 2\\nprint(int(z))\\n\",\n \"a = input()\\nb = int(a[:a.find(' ')])\\nc = int(a[a.find(' ') + 1:])\\nif b * c % 2 == 0:\\n\\tprint(int(b * c / 2))\\nelse:\\n\\tprint(int((b * c - 1) / 2))\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nans = 0\\nanss = 0\\nans = m * n\\nanss = ans // 2\\nprint(anss)\\n\",\n \"(m, n) = (int(x) for x in input().split(' '))\\nif m % 2 != 0 and n % 2 != 0:\\n\\ta = (m - 1) * n\\n\\tb = a / 2\\n\\tc = n / 2\\n\\ts = b + c\\n\\ts = int(s)\\n\\tprint(s)\\nelse:\\n\\ta = m * n / 2\\n\\ta = int(a)\\n\\tprint(a)\\n\",\n \"l = [int(n) for n in input().split()]\\nprint(l[0] * l[1] // 2)\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\nd = []\\nfor i in list_we_use:\\n\\td.append(int(i))\\ns = d[0] * d[1] / 2\\nprint(int(s))\\n\",\n \"dom = input().split()\\nN = int(dom[0])\\nM = int(dom[1])\\nprint(int(N * M / 2))\\n\",\n \"rect_board_size = input()\\nsquare_board = rect_board_size.split(' ')\\nno_of_squares = int(square_board[0]) * int(square_board[1])\\nprint(no_of_squares // 2)\\n\",\n \"import sys\\n(n, m) = input().split()\\nspaces = int(n) * int(m)\\nprint(int(spaces / 2))\\n\",\n \"(M, N) = map(int, input().split())\\nS = M * N\\nif S % 2 == 0:\\n\\tn = int(S * 0.5)\\nelse:\\n\\tn = int((S - 1) * 0.5)\\nprint(n)\\n\",\n \"import sys\\ninputs = sys.stdin.readline().split()\\nm = int(inputs[0])\\nn = int(inputs[1])\\np = m * n\\nr = p // 2\\nprint(r)\\n\",\n \"def s():\\n\\t(m, n) = [int(x) for x in input().split(' ')]\\n\\tprint(int(m * n / 2))\\ns()\\n\",\n \"line = input().split(' ')\\nn1 = int(line[0])\\nn2 = int(line[1])\\nprint(n1 * n2 // 2)\\n\",\n \"i = input(str())\\nh = list(map(int, i.split(' ')))\\nsize = h[0] * h[1]\\nmaxNo = size // 2\\nprint(maxNo)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ntotal_squares = m * n\\nmax_dominoes = total_squares // 2\\nprint(max_dominoes)\\n\",\n \"from math import floor\\ndoska = input()\\n(dl, shir) = doska.split()\\ndl = int(dl)\\nshir = int(shir)\\ndominoshka = 2 * 1\\ndoska = dl * shir\\notvet = floor(doska / dominoshka)\\nprint(otvet)\\n\",\n \"l = input()\\na = l.split()\\nm = int(a[0])\\nn = int(a[1])\\nq = int(m / 2)\\nr = m - q * 2\\nif r == 0:\\n\\tans = q * n\\nelse:\\n\\tans = q * n + int(n / 2)\\nprint(ans)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\na = m * n // 2\\nprint(a)\\n\",\n \"i = [int(x) for x in input().split()]\\nM = i[0]\\nN = i[1]\\nif M % 2 == 0:\\n\\tn = M / 2 * N\\nelif N % 2 == 0:\\n\\tn = N / 2 * M\\nelse:\\n\\tn = (M * N - 1) / 2\\nprint(int(n))\\n\",\n \"(a, b) = map(int, input().split())\\ninto = a * b\\ntot = into / 2\\nprint(int(tot))\\n\",\n \"m = list(map(int, input().split()))\\nn = 1\\nfor i in m:\\n\\tn *= i\\nprint(int(n // 2))\\n\",\n \"masukan = [int(item) for item in input().split(' ')]\\nluas = masukan[0] * masukan[1]\\nprint(int(luas / 2))\\n\",\n \"def maxPieces(m, n):\\n\\tresp = 0\\n\\tif m == 1:\\n\\t\\tresp = int(n / 2)\\n\\telse:\\n\\t\\tresp = maxPieces(m - 1, n) + int(n / 2)\\n\\treturn resp\\nmsj = input()\\ninpu = msj.split()\\nans = 0\\nm = int(inpu[0])\\nn = int(inpu[1])\\nif n % 2 == 0:\\n\\tans = maxPieces(m, n)\\nelse:\\n\\tans = maxPieces(m, n) + int(m / 2)\\nprint(ans)\\n\",\n \"a = input()\\na = a.split()\\nM = int(a[0])\\nN = int(a[1])\\nprint(M * N // 2)\\n\",\n \"(a, b) = list(map(int, input().split()))\\nc = a * b\\nd = 2\\nn = int(c / 2)\\nif n * 2 <= c:\\n\\tprint(n)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\na = 2\\nr = range(1, 17)\\nif m in r and n in r:\\n\\tif m * n % a == 0:\\n\\t\\tprint(m * n // a)\\n\\telif m > a and n > a:\\n\\t\\tc = m * math.floor(n / a) + math.floor(m / a)\\n\\t\\tprint(c)\\n\\telif m < a:\\n\\t\\tprint(math.floor(n / a))\\n\\telse:\\n\\t\\tprint(math.floor(m / a))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nsq = m * n\\nres = int(sq / 2)\\nprint(res)\\n\",\n \"splits = input().split()\\nm = int(splits[0])\\nn = int(splits[1])\\nprint(int(m * n / 2))\\n\",\n \"(m, n) = [int(num) for num in input().split()]\\nmatrix = n * m\\nif matrix % 2 == 0:\\n\\tprint(matrix // 2)\\nelse:\\n\\tprint((matrix - 1) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nsq = m * n\\nif sq <= 1:\\n\\tprint(0)\\nelif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(sq / 2))\\nelse:\\n\\tprint(int(sq / 2))\\n\",\n \"import math\\nstring = input()\\n(x, y) = string.split(' ')\\nx = int(x)\\ny = int(y)\\nresult = math.floor(x * y / 2)\\nprint(result)\\n\",\n \"(M, N) = map(int, input().split())\\nif M % 2 == 0:\\n\\tx = int(M / 2 * N)\\nif M % 2 == 1:\\n\\ta = M // 2 * N\\n\\tb = N // 2\\n\\tx = int(a + b)\\nprint(x)\\n\",\n \"def Domino():\\n\\tmn_ = input()\\n\\tmn = mn_.split()\\n\\tm = int(mn[0])\\n\\tn = int(mn[1])\\n\\tprint(int(n * m / 2))\\nDomino()\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\ny = a * b\\nz = y // 2\\nprint(z)\\n\",\n \"s = input()\\np = list(map(int, s.split()))\\nm = p[0]\\nn = p[1]\\nif m * n % 2 == 0:\\n\\tprint(int(n * m / 2))\\nelse:\\n\\tprint(int((m - 1) * n / 2 + n // 2))\\n\",\n \"num = input().split(' ')\\nprint(int(int(num[0]) * int(num[1]) / 2))\\n\",\n \"from math import floor\\nrdl = input().split()\\nprint(floor(int(rdl[0]) * int(rdl[1]) / 2))\\n\",\n \"line1 = input().split()\\n(m, n) = (int(line1[0]), int(line1[1]))\\nmax_side = max(m, n)\\nmin_side = min(m, n)\\ndominoes = max_side // 2 * min_side\\ndominoes += max_side % 2 * (min_side // 2)\\nprint(dominoes)\\n\",\n \"(M, N) = input().split()\\n(M, N) = (int(M), int(N))\\nk = M * N\\nprint(k // 2)\\n\",\n \"import math\\n\\ndef main():\\n\\t(a, b) = map(int, input().split())\\n\\tprint(math.floor(a * b / 2))\\nmain()\\n\",\n \"(n, m) = list(map(int, input().split()))\\nif n % 2 == 0 or m % 2 == 0:\\n\\tprint(n * m // 2)\\nelse:\\n\\ts = max(n, m)\\n\\tl = min(n, m)\\n\\tprint((s - 1) * l // 2 + l // 2)\\n\",\n \"(n, m) = map(int, input().split())\\nrez = int((n - n % 2) * (m - m % 2) / 2)\\nprimalatura = m // 2 if n % 2 == 1 else 0\\nadoualatura = n // 2 if m % 2 == 1 else 0\\nrez = rez + primalatura + adoualatura\\nprint(rez)\\n\",\n \"inp = input()\\nl = int(inp.split(' ')[0])\\nb = int(inp.split(' ')[1])\\narea = l * b\\nprint(area // 2)\\n\",\n \"import math\\nline = input()\\npieces = line.split()\\nm = int(pieces[0])\\nn = int(pieces[1])\\nprint(math.floor(m * n / 2))\\n\",\n \"a = input()\\naint = a.split(' ')\\nfor i in range(2):\\n\\taint[i] = int(aint[i])\\nresult = aint[0] * aint[1] // 2\\nprint(result)\\n\",\n \"n = input().split()\\nsurface = int(n[0]) * int(n[1])\\nnum_of_dominos = surface // 2\\nprint(num_of_dominos)\\n\",\n \"from sys import stdin, stdout\\n(a, b) = stdin.readline().split()\\nc = str(int(int(a) * int(b) / 2))\\nstdout.write(c)\\n\",\n \"(x, y) = map(int, input().split())\\nm = max(x, y)\\nn = min(x, y)\\nif m % 2 == 0:\\n\\tprint(m * n // 2)\\nelse:\\n\\tprint((m - 1) * n // 2 + n // 2)\\n\",\n \"import math\\n(n, m) = map(int, input().split())\\nval = math.floor(n * m * 0.5)\\nprint(val)\\n\",\n \"inp = input()\\nboard = inp.split(' ')\\nsquares = int(board[0]) * int(board[1])\\nprint(squares // 2)\\n\",\n \"(M, N) = [int(s) for s in input().rstrip().split(' ')]\\nprint(M * N // 2)\\n\",\n \"import sys\\nfor line in sys.stdin:\\n\\ts = line.split(' ')\\n\\tm = int(s[0])\\n\\tn = int(s[1])\\n\\tprint(m * n // 2)\\n\\tbreak\\n\",\n \"nXm = list(input().split(' '))\\nn = int(nXm[0])\\nm = int(nXm[1])\\nif n * m % 2 == 0:\\n\\tprint(n * m // 2)\\nelse:\\n\\tprint((n * m - 1) // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nif M >= 1 and N <= 16:\\n\\tprint(int(M * N / 2))\\n\",\n \"l = []\\nbrr = []\\narr = str(input())\\nbrr = arr.split(' ')\\nl = [y for y in brr if y != '']\\nprint(int(l[0]) * int(l[1]) // 2)\\n\",\n \"entrada = list((int(x) for x in input().split()))\\nprint(entrada[0] * entrada[1] // 2)\\n\",\n \"import math\\nboard = input()\\nm = int(board.split(' ')[0])\\nn = int(board.split(' ')[-1])\\narea = m * n\\noutput = math.floor(area / 2)\\nprint(output)\\n\",\n \"arr = input().split()\\nM = int(arr[0])\\nN = int(arr[1])\\nprint(int(M * N / 2))\\n\",\n \"N = input()\\nn = int(N.split()[0])\\nm = int(N.split()[1])\\np = n * m\\nprint(int(p / 2))\\n\",\n \"def Dominopiling():\\n\\t(m, n) = map(int, input().split())\\n\\tif m < 1 or m > 16:\\n\\t\\tprint('OOOOPS' + 'Between 1 and 16 please')\\n\\t\\texit()\\n\\tif n < 1 or n > 16:\\n\\t\\tprint('OOOOPS' + 'Between 1 and 16 please')\\n\\t\\texit()\\n\\tM = m * n\\n\\tdomino = M / 2\\n\\tprint(int(domino))\\nDominopiling()\\n\",\n \"from sys import stdin, stdout\\n(m, n) = map(int, stdin.readline().split())\\nprint(m * n // 2)\\n\",\n \"(len1, len2) = map(int, input().split())\\nprint(int(int(len1 * len2) / 2))\\n\",\n \"while True:\\n\\t(m, n) = [int(x) for x in input('').split()]\\n\\tif m >= 1 and m <= 16 and (n >= 1) and (n <= 16):\\n\\t\\tbreak\\nnum = m * n // 2\\nprint(num)\\n\",\n \"a = input()\\nc = a.split()\\nn_1 = int(c[0]) // 2 * int(c[1])\\nif int(c[0]) % 2 != 0:\\n\\tn_2 = int(c[1]) // 2\\nelse:\\n\\tn_2 = 0\\nprint(n_1 + n_2)\\n\",\n \"args = [int(x) for x in input().split(' ')]\\nM = args[0]\\nN = args[1]\\nprint(str(M * N // 2))\\n\",\n \"inp = input().split()\\nm = int(inp[0])\\nn = int(inp[1])\\nmRest = m % 2\\ncount = 0\\ncount += int(m / 2) * n\\nif mRest == 1:\\n\\tcount += int(n / 2)\\nprint(count)\\n\",\n \"import random\\nstr1 = input()\\n(m, n) = str1.split(' ', 1)\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0 or n % 2 == 0:\\n\\tret = m * n // 2\\nelse:\\n\\tret = (m * n - 1) // 2\\nprint(ret)\\n\",\n \"(n, m) = map(int, input().split(' '))\\narea = n * m\\ndomino_area = 2 * 1\\nprint(area // domino_area)\\n\",\n \"arr = list(map(int, input().split()))\\nk = arr[0] * arr[1]\\nprint(int(k / 2))\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\nresult = int(s / 2)\\nprint(result)\\n\",\n \"(m, n) = map(int, input().split())\\nd = 2\\nans = m * n // d\\nprint(ans)\\n\",\n \"dimensions = input()\\nm_n = dimensions.split()\\nm = int(m_n[0])\\nn = int(m_n[1])\\nif m == 1 and n == 1:\\n\\tcount = 0\\n\\tprint(count)\\nelse:\\n\\tif m == 1:\\n\\t\\ti = 0\\n\\t\\td_count = 0\\n\\t\\tif n % 2 == 0:\\n\\t\\t\\twhile i < n:\\n\\t\\t\\t\\ti += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\telse:\\n\\t\\t\\twhile i <= n:\\n\\t\\t\\t\\ti += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\t\\td_count -= 1\\n\\telif n == 1:\\n\\t\\tj = 0\\n\\t\\td_count = 0\\n\\t\\tif m % 2 == 0:\\n\\t\\t\\twhile j < m:\\n\\t\\t\\t\\tj += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\telse:\\n\\t\\t\\twhile j <= m:\\n\\t\\t\\t\\tj += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\t\\td_count -= 1\\n\\telif m % 2 == 0:\\n\\t\\ti = 0\\n\\t\\td_count = 0\\n\\t\\twhile i < m:\\n\\t\\t\\ti += 2\\n\\t\\t\\td_count += 1\\n\\t\\td_count = d_count * n\\n\\telse:\\n\\t\\tj = 0\\n\\t\\td_count = 0\\n\\t\\tif m % 2 == 0:\\n\\t\\t\\twhile j < m:\\n\\t\\t\\t\\tj += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\telse:\\n\\t\\t\\twhile j <= m:\\n\\t\\t\\t\\tj += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\td_count -= 1\\n\\t\\td_count = d_count * n\\n\\t\\ti = 0\\n\\t\\tif n % 2 == 0:\\n\\t\\t\\twhile i < n:\\n\\t\\t\\t\\ti += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\telse:\\n\\t\\t\\twhile i <= n:\\n\\t\\t\\t\\ti += 2\\n\\t\\t\\t\\td_count += 1\\n\\t\\t\\td_count = d_count - 1\\n\\tprint(d_count)\\n\",\n \"def solve():\\n\\t(M, N) = map(int, input().split())\\n\\tif M < 2 and N < 2:\\n\\t\\tprint(0)\\n\\t\\treturn\\n\\tif M < N:\\n\\t\\t(M, N) = (N, M)\\n\\tres = N * (M // 2) + (N // 2 if M % 2 else 0)\\n\\tprint(res)\\nsolve()\\n\",\n \"import math as mat\\n(m, n) = map(int, input().split())\\nans = m * n\\nif ans % 2 == 0:\\n\\tans = ans / 2\\n\\tprint(int(ans))\\nelse:\\n\\tans = mat.ceil(ans / 2)\\n\\tans = ans - 1\\n\\tprint(ans)\\n\",\n \"(m, n) = str(input()).split(' ')\\nm = int(m)\\nn = int(n)\\nprint(int(m * n / 2))\\n\",\n \"num = input()\\nmylist = num.split(' ')\\nm = mylist[0]\\nn = mylist[1]\\nif int(m) >= 1 and int(m) <= 16 and (int(n) >= 1) and (int(n) <= 16):\\n\\tdominos = int(m) * int(n)\\n\\tava = dominos // 2\\n\\tprint(ava)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nprint(n // 2 * m + m // 2 * (n % 2 != 0))\\n\",\n \"(m, n) = list(map(int, input().split()))\\narea_domino = 2\\narea_sqr = m * n\\nprint(area_sqr // area_domino)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nrect = m * n\\ndom = rect // 2\\nprint(dom)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\ntotalSpace = m * n\\nnumofDominos = totalSpace // 2\\nprint(numofDominos)\\n\",\n \"p = [int(x) for x in input().split(' ')]\\nk = p[0] * p[1]\\na = int(k / 2)\\nprint(a)\\n\",\n \"import math\\nn = input().split(' ')\\nprint(math.floor(int(n[0]) * int(n[1]) / 2))\\n\",\n \"num = input('').split()\\na = int(num[0])\\nb = int(num[1])\\narea = a * b\\nprint(area // 2)\\n\",\n \"def func():\\n\\t(m, n) = (int(i) for i in input().split())\\n\\tif m * n % 2:\\n\\t\\tprint((m * n - 1) // 2)\\n\\telse:\\n\\t\\tprint(m * n // 2)\\nfunc()\\n\",\n \"l = input().split()\\nx = int(l[0]) * int(l[1])\\nprint(x // 2)\\n\",\n \"A = input()\\nA = A.split()\\nprint(int(A[0]) * int(A[1]) // 2)\\n\",\n \"(a, b) = [int(a) for a in input().split()]\\narea = a * b\\nprint(area // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nc = m * n // 2\\nprint(c)\\n\",\n \"import math\\n(n, m) = [int(x) for x in input().split()]\\nl = max(n, m)\\nw = min(n, m)\\nif l / 2 == l // 2:\\n\\tnum = l / 2 * w\\nelse:\\n\\tnum = math.floor(l / 2) * w + math.floor(w / 2)\\nprint(int(num))\\n\",\n \"tile_size = 2\\nfield_size = tuple(map(int, input().split(' ')))\\nresult = field_size[0] // tile_size * field_size[1] if not field_size[0] % tile_size else field_size[0] // tile_size * field_size[1] + field_size[1] // tile_size\\nprint(result)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\ncount = 0\\nwhile m > 1:\\n\\tcount += n\\n\\tm -= 2\\nif m == 1:\\n\\tcount += math.floor(n / 2)\\nprint(count)\\n\",\n \"import math as m\\nx = list(map(int, input().split()))\\ny = x[0] * x[1]\\nt = m.floor(y / 2)\\nprint(t)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nb = a % 2\\nif b == 0:\\n\\ti = a / 2\\nelse:\\n\\tc = a - 1\\n\\ti = c / 2\\np = int(i)\\nprint(p)\\n\",\n \"list_ = [int(x) for x in input().split(' ')]\\nm = list_[0]\\nn = list_[1]\\nprint(int(m * n / 2))\\n\",\n \"inp = input().split()\\n(n, m) = (int(inp[0]), int(inp[1]))\\nif n == 1 and m == 1:\\n\\tprint(0)\\n\\texit(0)\\nans = max(n // 2 * m + (n - n // 2 * 2) * (m // 2), m // 2 * n + (m - m // 2 * 2) * (n // 2))\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\ty = m // 2\\n\\tprint(y * n)\\nelse:\\n\\ty = m // 2\\n\\tt = y * n\\n\\tr = n // 2\\n\\tprint(t + r)\\n\",\n \"from array import *\\nints = input('').split(' ')\\nfor i in range(len(ints)):\\n\\tints[i] = int(ints[i])\\n(m, n) = (ints[0], ints[1])\\nfittable = 0\\nT = [[0 for x in range(m)] for y in range(n)]\\nfor i in range(len(T)):\\n\\tcount = 0\\n\\tfor j in range(len(T[i])):\\n\\t\\tcount += 1\\n\\t\\tif count >= 2:\\n\\t\\t\\tfittable += 1\\n\\t\\t\\tcount = 0\\nif m % 2 != 0:\\n\\tif n % 2 != 0:\\n\\t\\tfittable += (n - 1) / 2\\n\\telse:\\n\\t\\tfittable += n / 2\\nprint(int(fittable))\\n\",\n \"user_input = input()\\nm = int(user_input.split()[0])\\nn = int(user_input.split()[1])\\nrectangles = m * n // 2\\nprint(rectangles)\\n\",\n \"import sys\\n\\ndef max_num_dominoes(m, n):\\n\\tp = m * n\\n\\tif p % 2 == 0:\\n\\t\\treturn p // 2\\n\\telse:\\n\\t\\treturn m * (n - 1) // 2 + (m - 1) // 2\\n\\ndef main(args):\\n\\tlines = sys.stdin.readlines()\\n\\tm_n = map(int, lines[0].split())\\n\\tm = next(m_n)\\n\\tn = next(m_n)\\n\\tprint(max_num_dominoes(m, n))\\nmain(sys.argv)\\n\",\n \"(m, n) = map(int, input().split())\\ncuadrados = m * n\\nfichas = cuadrados // 2\\nprint(fichas)\\n\",\n \"(M, N) = map(int, input().split())\\nans = M * N // 2\\nprint(str(ans))\\n\",\n \"data = input().split(' ')\\nm = int(data[0])\\nn = int(data[1])\\nif m >= 1 and m <= n and (n >= m) and (n <= 16):\\n\\tboard = m * n\\n\\tprint(str(int(board / 2)))\\n\",\n \"import sys, functools, operator\\nprint(functools.reduce(operator.mul, [int(i) for i in sys.stdin.readline().split()]) // 2)\\n\",\n \"def putDomino():\\n\\ttableParams = [int(parameter) for parameter in input().split()]\\n\\tdominoMax = countNumDomino(tableParams)\\n\\tprintToConsole(dominoMax)\\n\\ndef countNumDomino(tableParams):\\n\\ttableLength = tableParams[0]\\n\\ttableWidth = tableParams[1]\\n\\ttableSize = tableLength * tableWidth\\n\\tdominoMax = tableSize // 2\\n\\treturn dominoMax\\n\\ndef printToConsole(dominoMax):\\n\\tprint(dominoMax)\\nputDomino()\\n\",\n \"[n, m] = input().split(' ')\\nsize = int(n) * int(m)\\nprint(int(size / 2))\\n\",\n \"from math import floor\\ns = input()\\na = s.find(' ')\\nm = int(s[:a])\\nn = int(s[a + 1:])\\nprint(floor(m * n / 2))\\n\",\n \"x = [int(i) for i in input().split()]\\nprint(x[0] * x[1] // 2)\\n\",\n \"line = input().split()\\n(M, N) = (int(line[0]), int(line[1]))\\nprint(int(M * N / 2))\\n\",\n \"i = input()\\nnumber = i.split()\\nM = int(number[0])\\nN = int(number[1])\\nif (M > 0 and M < 17) and (N > 0 and N < 17):\\n\\tprint(int(M * N / 2))\\n\",\n \"from sys import stdin\\nnums = [int(x) for x in stdin.readline().strip().split()]\\nprint(nums[0] * nums[1] // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nL = M * N\\nif L % 2 == 0:\\n\\tprint(int(L / 2))\\nif L % 2 == 1:\\n\\tprint(int((L - 1) / 2))\\n\",\n \"sum = 0\\ncount = 0\\n(m, n) = input('').split()\\nfor i in range(int(m)):\\n\\tfor j in range(int(n)):\\n\\t\\tcount += 1\\n\\t\\tif count == 2:\\n\\t\\t\\tsum += 1\\n\\t\\t\\tcount = 0\\nprint(sum)\\n\",\n \"(M, N) = map(int, input().split())\\nI = M * N // 2\\nprint(I)\\n\",\n \"import math\\na = input().split()\\nl = int(a[0])\\nd = int(a[1])\\nif d == 1:\\n\\tprint(int(math.floor(l / 2)))\\nelif d % 2 == 0:\\n\\tprint(int(l * d / 2))\\nelse:\\n\\tprint(int(l * (d - 1) / 2 + math.floor(l / 2)))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nc1 = m * (n // 2) + n % 2 * (m // 2)\\nc2 = n * (m // 2) + m % 2 * (n // 2)\\nprint(int(max(c1, c2)))\\n\",\n \"inp = input().split()\\nM = int(inp[0])\\nN = int(inp[1])\\nif M == 2 or N == 2:\\n\\tdom = M if N == 2 else N\\n\\tprint(dom)\\nelse:\\n\\tM_2 = M if M % 2 == 0 else M - 1\\n\\tN_2 = N if N % 2 == 0 else N - 1\\n\\tx = M_2 if M_2 == N_2 else min(M_2, N_2)\\n\\tdom = int(M_2 / 2) * N_2\\n\\tif M % 2 != 0 and N % 2 == 0:\\n\\t\\tdom = dom + int(N / 2)\\n\\telif M % 2 != 0 and N % 2 != 0:\\n\\t\\tdom = dom + int((M + N - 1) / 2)\\n\\telif N % 2 != 0 and M % 2 == 0:\\n\\t\\tdom = dom + int(M / 2)\\n\\tprint(dom)\\n\",\n \"a = input()\\nlista = [int(i) for i in a.split()]\\ntotal = lista[0] * lista[1]\\ndom = total // 2\\nprint(dom)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\na = math.floor(m / 2)\\nb = math.floor(n / 2)\\nc = math.ceil(m - 2 * a)\\nd = math.ceil(n - 2 * b)\\nt = 2 * a * b + c * b + d * a\\nprint(t)\\n\",\n \"(n, m) = map(int, input().split())\\nc = n // 2\\nk = m\\ne = 0\\nif n % 2 == 1:\\n\\te += m // 2\\nprint(c * k + e)\\n\",\n \"s = input()\\na = s.split(' ')\\nm = int(a[0])\\nn = int(a[1])\\nif n % 2 == 0 or m % 2 == 0:\\n\\tk = m * n // 2\\nelse:\\n\\tp = divmod(m, 2)\\n\\tx = p[0]\\n\\tq = divmod(n, 2)\\n\\ty = q[0]\\n\\tk = n * x + y\\nprint(k)\\n\",\n \"(M, N) = map(int, input().split())\\nif M % 2 == 0:\\n\\tnum = M * N // 2\\nelif N % 2 == 0:\\n\\tnum = M * N // 2\\nelse:\\n\\tnum = M * (N - 1) // 2 + (M - 1) // 2\\nprint(num)\\n\",\n \"rec = input().split()\\nM = int(rec[0])\\nN = int(rec[1])\\nif M < N:\\n\\t(M, N) = (N, M)\\nnum = M // 2 * N + M % 2 * (N // 2)\\nprint(num)\\n\",\n \"b = input().split(' ')\\nb = list(map(int, b))\\nprint(int(b[0] * b[1] / 2))\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\nb = []\\nfor i in list_we_use:\\n\\tb.append(int(i))\\nk = b[0] * b[1] / 2\\nprint(int(k))\\n\",\n \"import math\\n(m, n) = [int(s) for s in input().split()]\\na = 2\\nq = m * n / a\\nq = math.floor(q)\\nprint(q)\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef insr():\\n\\ts = input()\\n\\treturn list(s[:len(s) - 1])\\n\\ndef invr():\\n\\treturn map(int, input().split())\\nboard = inlt()\\nboardSize = board[0] * board[1]\\nprint(int((boardSize - boardSize % 2) / 2))\\n\",\n \"e = list(input() + ' ')\\nc = 0\\nd = ' '\\nn = ''\\nm = ''\\nb = 0\\nwhile b == 0:\\n\\tif e[c] == d:\\n\\t\\tb = 1\\n\\telse:\\n\\t\\tn = n + e[c]\\n\\tc = c + 1\\nwhile b == 1:\\n\\tif e[c] == d:\\n\\t\\tb = 2\\n\\telse:\\n\\t\\tm = m + e[c]\\n\\tc = c + 1\\nn = int(n)\\nm = int(m)\\nprint(n * m // 2)\\n\",\n \"def main():\\n\\t(n, m) = [int(v) for v in input().split()]\\n\\tprint(n * m // 2)\\nmain()\\n\",\n \"domino = 2\\nboard = input().split()\\nfor i in range(len(board)):\\n\\tboard[i] = int(board[i])\\nM = board[0]\\nN = board[1]\\narea = M * N\\nprint(area // 2)\\n\",\n \"from math import ceil\\nq = input().split()\\nprint(int(int(q[0]) * int(q[1]) / 2))\\n\",\n \"(m, n) = [int(i) for i in input().strip().split(' ')]\\nprint(m * n // 2)\\n\",\n \"numbers = input().split()\\nn1 = int(numbers[0])\\nn2 = int(numbers[1])\\nprint(int(n1 * n2 / 2))\\n\",\n \"from math import floor\\n(m, n) = map(int, input().split())\\nx = m * n / 2\\nz = floor(x)\\nprint(z)\\n\",\n \"(n, m) = map(int, input().split())\\nif m % 2 == 0:\\n\\tprint(n * (m // 2))\\nelif n % 2 == 0:\\n\\tprint(m * (n // 2))\\nelse:\\n\\tx = n * (m // 2) + n // 2\\n\\ty = m * (n // 2) + m // 2\\n\\tprint(max(x, y))\\n\",\n \"def maxDominos(m, n):\\n\\tx = m * n\\n\\tif x % 2 == 0:\\n\\t\\tdomino = x / 2\\n\\telse:\\n\\t\\tdomino = (x - 1) / 2\\n\\treturn int(domino)\\n(m, n) = map(int, input().split())\\nprint(maxDominos(m, n))\\n\",\n \"list1 = input().split()\\narea = int(list1[0]) * int(list1[1])\\nprint(int(area / 2))\\n\",\n \"mn = list(map(int, input().split()))\\nm = mn[0]\\nn = mn[1]\\ntot = 0\\nif m >= 2:\\n\\ttot = m // 2\\n\\tif m % 2 == 0:\\n\\t\\tprint(tot * n)\\n\\telse:\\n\\t\\tprint(tot * n + n // 2)\\nelif n >= 2:\\n\\ttot = n // 2\\n\\tif n % 2 == 0:\\n\\t\\tprint(tot * m)\\n\\telse:\\n\\t\\tprint(tot * m + m // 2)\\nelif m < 2 and n < 2:\\n\\tprint('0')\\n\",\n \"import math\\n(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nif m > 1 or n > 1:\\n\\tmx = math.floor(m / 2)\\n\\tm -= mx * 2\\n\\tres = mx * n\\n\\tif m > 0:\\n\\t\\tres += math.floor(n / 2)\\n\\tprint(res)\\nelse:\\n\\tprint('0')\\n\",\n \"(a, b) = list(map(int, input().split()))\\nif a * b % 2 == 0:\\n\\tprint(int(a * b / 2))\\nif a * b % 2 != 0:\\n\\tprint(int((a * b - a * b % 2) / 2))\\n\",\n \"s = input()\\ns = s.split(' ')\\nl = int(s[0])\\nw = int(s[1])\\nif l % 2 == 0:\\n\\ta = l * w // 2\\nelif w % 2 == 0:\\n\\ta = l * w // 2\\nelse:\\n\\ta = l * w // 2\\nprint(a)\\n\",\n \"(m, n) = list(map(int, input().rstrip().split()))\\ndominoes = m * n // 2\\nprint(dominoes)\\n\",\n \"i = input()\\nli = list(i.split(' '))\\na = int(li[0])\\nb = int(li[1])\\nprint(int(a) * int(b) // 2)\\n\",\n \"import random\\nd = input().split(' ')\\nwidth = int(d[0])\\nheight = int(d[1])\\nmatrix = []\\nfor i in range(height):\\n\\tmatrix.append([])\\nfor row in matrix:\\n\\tfor cell in range(width):\\n\\t\\trow.append({'flag': False})\\nconsumed_flags = set()\\nfor i in range(height):\\n\\tfor r in range(width):\\n\\t\\tflag = random.randint(0, 2 ** 32)\\n\\t\\tif not matrix[i][r].get('flag'):\\n\\t\\t\\tmatrix[i][r]['flag'] = flag\\n\\t\\t\\ttry:\\n\\t\\t\\t\\tif flag not in consumed_flags:\\n\\t\\t\\t\\t\\tnext_cell_in_row = r + 1 < width\\n\\t\\t\\t\\t\\tnext_cell_in_col = i + 1 < height\\n\\t\\t\\t\\t\\tif next_cell_in_row and (not matrix[i][r + 1].get('flag', 0)):\\n\\t\\t\\t\\t\\t\\tmatrix[i][r + 1]['flag'] = flag\\n\\t\\t\\t\\t\\t\\tconsumed_flags.add(flag)\\n\\t\\t\\t\\t\\telif next_cell_in_col and (not matrix[i + 1][r].get('flag', 0)):\\n\\t\\t\\t\\t\\t\\tmatrix[i + 1][r]['flag'] = flag\\n\\t\\t\\t\\t\\t\\tconsumed_flags.add(flag)\\n\\t\\t\\texcept IndexError as exc:\\n\\t\\t\\t\\tcontinue\\nprint(len(consumed_flags))\\n\",\n \"def domino():\\n\\t(m, n) = map(int, input().split())\\n\\treturn m * n // 2\\nprint(domino())\\n\",\n \"x = input()\\ntarget = 1\\nm = ''\\nn = ''\\nfor letter in x:\\n\\tif letter == ' ':\\n\\t\\ttarget += 1\\n\\telse:\\n\\t\\tif target == 1:\\n\\t\\t\\tm += letter\\n\\t\\tif target == 2:\\n\\t\\t\\tn += letter\\nm = int(m)\\nn = int(n)\\nmfix = False\\nnfix = False\\nif m / 2 != float(int(m / 2)):\\n\\tmfix = True\\nif n / 2 != float(int(n / 2)):\\n\\tnfix = True\\ntotal = 0\\nm1 = m - 1\\nn1 = n - 1\\nif mfix == True:\\n\\tif nfix == True:\\n\\t\\ttotal += m1 * int(n / 2)\\n\\t\\ttotal += int(m / 2)\\n\\t\\ttotal += int(n / 2)\\n\\telse:\\n\\t\\ttotal += m * int(n / 2)\\nelse:\\n\\ttotal += n * int(m / 2)\\nprint(total)\\n\",\n \"(M, N) = map(int, input().split())\\nbox = M * N\\nprint(box // 2)\\n\",\n \"(n, m) = map(int, input().split())\\ns = n * m\\nx = s // 2\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\nnum = m * n\\nif num % 2 == 1:\\n\\tx = (num - 1) / 2\\nif num % 2 == 0:\\n\\tx = num / 2\\nprint(int(x))\\n\",\n \"(a, b) = map(int, input().strip().split()[:2])\\nr = a * b // 2\\nprint(r)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nres = m * n // 2\\nprint(res)\\n\",\n \"board = [int(num) for num in input().split(' ')]\\n\\ndef calculateSquaresWhenEven(num1, num2):\\n\\treturn num1 * num2 / 2\\nif board[0] % 2 == 0 and board[1] % 2 == 0:\\n\\tprint(int(calculateSquaresWhenEven(board[0], board[1])))\\nelif board[0] % 2 != 0 and board[1] % 2 != 0:\\n\\tSecureSquare = calculateSquaresWhenEven(board[0] - 1, board[1] - 1)\\n\\trestOfBoard = (board[0] - 1) / 2 + (board[1] - 1) / 2\\n\\tprint(int(SecureSquare + restOfBoard))\\nelse:\\n\\tif board[0] % 2 != 0:\\n\\t\\tSecureSquare = calculateSquaresWhenEven(board[0] - 1, board[1])\\n\\t\\trestOfBoard = board[1] / 2\\n\\telse:\\n\\t\\tSecureSquare = calculateSquaresWhenEven(board[0], board[1] - 1)\\n\\t\\trestOfBoard = board[0] / 2\\n\\tprint(int(SecureSquare + restOfBoard))\\n\",\n \"size = list(map(int, input().split()))\\nrows = size[0]\\ncols = size[1]\\ndominos = 0\\nif rows % 2 == 0:\\n\\twhile rows > 1:\\n\\t\\trows -= 2\\n\\t\\tdominos += cols\\nelse:\\n\\twhile rows > 1:\\n\\t\\trows -= 2\\n\\t\\tdominos += cols\\n\\twhile cols > 1:\\n\\t\\tcols -= 2\\n\\t\\tdominos += 1\\nprint(dominos)\\n\",\n \"(m, n) = map(int, input().split())\\nq1 = n // 2 * m\\nif n % 2 == 1:\\n\\tq1 += m // 2\\nprint(q1)\\n\",\n \"from sys import stdin, stdout\\n\\ndef trace(f):\\n\\n\\tdef traced(*args, **kw):\\n\\t\\tprint('calling {} with args {}, {}'.format(f.__name__, args, kw))\\n\\t\\treturn f(*args, **kw)\\n\\treturn traced\\n\\n@trace\\ndef f(x):\\n\\tprint(x)\\n\\ndef read():\\n\\treturn stdin.readline()[:-1]\\n\\ndef readarr(sep=None, maxsplit=-1):\\n\\treturn read().split(sep, maxsplit)\\n\\ndef readint():\\n\\treturn int(read())\\n\\ndef readintarr(sep=None, maxsplit=-1):\\n\\treturn [int(a) for a in readarr(sep, maxsplit)]\\n\\ndef write(*args, **kwargs):\\n\\tsep = kwargs.get('sep', ' ')\\n\\tend = kwargs.get('end', '\\\\n')\\n\\tstdout.write(sep.join((str(a) for a in args)) + end)\\n\\ndef writearr(arr, sep=' ', end='\\\\n'):\\n\\tstdout.write(sep.join((str(a) for a in arr)) + end)\\n(M, N) = readintarr()\\nmx = max(M, N)\\nmn = min(M, N)\\nr = int(mx / 2 * mn)\\nwrite(r)\\n\",\n \"(n, k) = [int(x) for x in input().split()]\\nprint(n * k // 2)\\n\",\n \"x = input()\\nx = [i for i in map(int, x.split(' '))]\\nsc = x[0] * x[1]\\nprint(sc // 2)\\n\",\n \"i = lambda : map(int, input().split())\\n(m, n) = i()\\nif m % 2 == 1:\\n\\tx = (n * (m - 1) + n) / 2\\nelse:\\n\\tx = m * n / 2\\nz = abs(x)\\nif z == x:\\n\\tprint(int(z))\\nelse:\\n\\tprint(int(z + 1))\\n\",\n \"numbers = input()\\nnumber = numbers.split(' ')\\nprint(int(int(number[0]) * int(number[1]) / 2))\\n\",\n \"MN = input().split()\\nM = int(MN[0])\\nN = int(MN[1])\\nif M * N % 2 == 0:\\n\\toutput = int(M * N / 2)\\nelse:\\n\\toutput = int((M * N - 1) / 2)\\nprint(output)\\n\",\n \"(n, m) = map(int, input().split())\\nif n <= m <= 16:\\n\\tprint(m * n // 2)\\n\",\n \"user_input = str(input())\\nif len(user_input) == 3:\\n\\tM = int(user_input[0])\\n\\tN = int(user_input[2])\\nelif len(user_input) == 4:\\n\\tM = int(user_input[0])\\n\\tN = int(user_input[2:4])\\nelse:\\n\\tM = int(user_input[0:2])\\n\\tN = int(user_input[3:5])\\nif M >= 1 and N <= 16 and (N >= M):\\n\\tanswer = M * N // 2\\n\\tprint(answer)\\n\",\n \"import math\\n(a, b) = input().split()\\na = int(a)\\nb = int(b)\\ns = a * b\\nk = math.floor(s / 2)\\nprint(k)\\n\",\n \"input_str = str(input())\\nl = input_str.split(' ')\\nn = int(l[0])\\nm = int(l[1])\\na = 2\\nresult = 0\\nif n * m == a:\\n\\tresult = 1\\nelif n == 1:\\n\\tresult = m // a\\nelif m == 1:\\n\\tresult = n // a\\nelse:\\n\\tresult = n * m // a\\nprint(result)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nif m % 2 == 0 and n % 2 == 0:\\n\\tsum = m * n / 2\\nelif m % 2 != 0 and n % 2 != 0:\\n\\tsum = m * n // 2\\nelse:\\n\\tsum = m * n / 2\\nprint(int(sum))\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nr = m * n\\nprint(r // 2)\\n\",\n \"(M, N) = [int(x) for x in input().split(' ')]\\nif M in range(0, 17) and N in range(0, 17):\\n\\tA = int(M * N / 2)\\n\\tprint(A)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\noutput = area // 2\\nprint(output)\\n\",\n \"def cal(n, m):\\n\\treturn (n * m - n * m % 2) // 2\\na = list(map(int, input().split()))\\nprint(cal(a[0], a[1]))\\n\",\n \"(A, B) = map(int, input().split())\\nprint(A * B // 2)\\n\",\n \"(n, m) = map(int, input().split())\\nb = n * m\\nr = b // 2\\nprint(r)\\n\",\n \"x = input().split()\\nfor a in range(len(x)):\\n\\tx[a] = int(x[a])\\nb = x[0] * x[1]\\nb = int(b / 2)\\nprint(b)\\n\",\n \"(m_height, n_length) = list(map(int, input().split()))\\nif m_height < 1 or m_height > n_length or n_length > 16:\\n\\tprint('Wrong input')\\n\\texit()\\ncount_dominos = 0\\nis_vertical = False\\nfor row in range(m_height):\\n\\ttemp_n = n_length\\n\\twhile True:\\n\\t\\tif temp_n - 2 >= 0:\\n\\t\\t\\ttemp_n -= 2\\n\\t\\t\\tcount_dominos += 1\\n\\t\\telif temp_n - 2 == -1 and m_height - row >= 2 and (not is_vertical):\\n\\t\\t\\ttemp_n -= 2\\n\\t\\t\\tcount_dominos += 1\\n\\t\\t\\tis_vertical = True\\n\\t\\t\\tbreak\\n\\t\\telif temp_n - 2 == -1 and is_vertical:\\n\\t\\t\\ttemp_n -= 2\\n\\t\\t\\tis_vertical = False\\n\\t\\t\\tbreak\\n\\t\\telse:\\n\\t\\t\\tbreak\\nprint(count_dominos)\\n\",\n \"s = [int(n) for n in input().split()]\\nprint(s[0] * s[1] // 2)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nnp = area // 2\\nprint(np)\\n\",\n \"(panjang, lebar) = map(int, input().split())\\nif panjang % 2 == 0:\\n\\tprint(panjang // 2 * lebar)\\nelif lebar % 2 == 0:\\n\\tprint(lebar // 2 * panjang)\\nelse:\\n\\tprint(panjang // 2 * lebar + lebar // 2)\\n\",\n \"sizes = list(map(int, input().split()))\\nm = sizes[0]\\nn = sizes[1]\\nS = m * n\\nres = S // 2\\nprint(res)\\n\",\n \"n = [int(x) for x in input().split()]\\na = n[0]\\nb = n[1]\\nprint(a * b // 2)\\n\",\n \"(n, m) = map(int, input().split())\\nfin = n // 2 * m\\nif n % 2 != 0:\\n\\tfin += m // 2\\nprint(fin)\\n\",\n \"def solver(n, m):\\n\\treturn n * m // 2\\n(n, m) = map(int, input().split())\\nprint(solver(n, m))\\n\",\n \"def foo(x, y):\\n\\tprint(int(x * y / 2))\\n(x, y) = input().split()\\n(x, y) = [int(x), int(y)]\\nfoo(x, y)\\n\",\n \"L = input().split(' ')\\n(M, N) = (int(L[0]), int(L[1]))\\nprint(M * N // 2)\\n\",\n \"desk_size = input().split(' ')\\ndesk_square = int(desk_size[0]) * int(desk_size[1])\\nprint(desk_square // 2)\\n\",\n \"import math\\ns = str.split(input())\\nM = int(s[0])\\nN = int(s[1])\\nif M % 2 == 0 or N % 2 == 0:\\n\\tprint(int(M * N / 2))\\nelif M % 2 == 0:\\n\\tprint(int(M * (N - 1) / 2 + math.floor(M / 2)))\\nelif N % 2 == 0:\\n\\tprint(int(N * (M - 1) / 2 + math.floor(N / 2)))\\nelse:\\n\\tprint(int(M * (N - 1) / 2 + math.floor(M / 2)))\\n\",\n \"e = list(map(int, input().split()))\\na = int(e[0]) * int(e[1])\\nn = a // 2\\nprint(n)\\n\",\n \"a = input().split()\\nx = int(a[0])\\ny = int(a[1])\\nif x % 2 == 0 or y % 2 == 0:\\n\\tn = x * y / 2\\nif x % 2 != 0 and y % 2 != 0:\\n\\tn = x * y // 2\\nprint(int(n))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nt = m * n\\nf = t // 2\\nprint(f)\\n\",\n \"(r, j) = input().split()\\nprint(int(r) * int(j) // 2)\\n\",\n \"(n, m) = map(int, input().split())\\nc = 0\\nif n >= 2:\\n\\tc += n // 2 * m\\n\\tif n % 2 != 0:\\n\\t\\tc += m // 2\\nelif m >= 2:\\n\\tc += m // 2 * n\\n\\tif m % 2 != 0:\\n\\t\\tc += n // 2\\nprint(c)\\n\",\n \"from math import ceil\\nimport re\\nentrada = input()\\nmatch = re.search('(\\\\\\\\d*) (\\\\\\\\d*)', entrada)\\nm = int(match.group(1))\\nn = int(match.group(2))\\nif m % 2 != 0 and n % 2 != 0:\\n\\tresultado = m * n // 2\\nelse:\\n\\tresultado = m * n // 2\\nprint(resultado)\\n\",\n \"n = list(map(int, input().split()))\\na = n[0] * n[1]\\nfor i in range(1, a + 1):\\n\\tm = i * 2\\n\\tif a == 1:\\n\\t\\tprint(0)\\n\\t\\tbreak\\n\\telif a == m:\\n\\t\\tprint(i)\\n\\t\\tbreak\\n\\telif a < m:\\n\\t\\tprint(i - 1)\\n\\t\\tbreak\\n\",\n \"data = input()\\ndims = data.split(' ')\\nm = int(dims[0])\\nn = int(dims[1])\\nprint(int(n * m / 2))\\n\",\n \"Dim = input().split()\\nlmeo = int(Dim[0]) * int(Dim[1])\\nanswer = lmeo // 2\\nprint(int(answer))\\n\",\n \"(x, m) = map(int, input().split())\\nprint(x * m // 2)\\n\",\n \"(x, y) = map(int, input().split())\\nif x == 1 or y == 1:\\n\\tif x >= y:\\n\\t\\tprint(x // 2)\\n\\telse:\\n\\t\\tprint(y // 2)\\nelse:\\n\\tprint(x * y // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\n(a, b) = (2, 1)\\nif m % a != 0:\\n\\tmx = m // a\\n\\tmx = mx * n\\n\\tnx = n // 2\\n\\tx = mx + nx\\nelse:\\n\\tmx = m // a\\n\\tx = mx * n\\nprint(x)\\n\",\n \"(a, b) = map(int, input().split())\\na = int(a * b)\\nm = int(a / 2)\\nprint(m)\\n\",\n \"import sys\\nfirst_line = str(input()).split()\\nm = int(first_line[0])\\nn = int(first_line[1])\\nif m + n < 2:\\n\\tprint(0)\\nelse:\\n\\tprint(int(m * n / 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m <= n:\\n\\tA = m * n\\n\\tT = A // 2\\nprint(T)\\n\",\n \"(M, N) = map(int, input().split())\\nnum = M * N // 2\\nprint(num)\\n\",\n \"(M, N) = input().split(' ')\\nN = int(N)\\nM = int(M)\\n\\ndef counter(m, n):\\n\\tif m == 1 and n == 1:\\n\\t\\treturn 0\\n\\tif m == 1 and n % 2 == 0:\\n\\t\\treturn int(n / 2)\\n\\tif m == 1 and n % 2 == 1:\\n\\t\\treturn int((n - 1) / 2)\\n\\tif m % 2 == 0 and n % 2 == 0:\\n\\t\\treturn int(m * n / 2)\\n\\tif m % 2 == 0 and n % 2 == 1:\\n\\t\\treturn int(m * (n - 1) / 2) + counter(1, m)\\n\\tif m % 2 == 1:\\n\\t\\treturn counter(1, n) + int((m - 1) * n / 2)\\nprint(counter(M, N))\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nmatrix = n * m\\nres = 0\\nif matrix % 2 == 0:\\n\\tres = matrix // 2\\nelse:\\n\\tres = matrix // 2\\nprint(res)\\n\",\n \"import math\\na = [int(x) for x in input().split()]\\nb = a[0] * a[1]\\nprint(math.floor(int(b / 2)))\\n\",\n \"from math import floor\\n\\ndef main(status=int(0)):\\n\\n\\tdef solution():\\n\\t\\t(m, n) = map(int, input().split())\\n\\t\\tprint(max(floor(m / 2 * n), floor(n / 2 * m)))\\n\\tsolution()\\n\\treturn status\\nmain()\\n\",\n \"(m, n) = map(int, input().split())\\nres = 0\\nif m < 2 and n < 1 or (m < 1 and n < 2):\\n\\tprint(0)\\nelif m > n:\\n\\tres = m // 2 * n\\n\\tif m % 2 == 1:\\n\\t\\tres += n // 2\\nelse:\\n\\tres = n // 2 * m\\n\\tif n % 2 == 1:\\n\\t\\tres += m // 2\\nprint(res)\\n\",\n \"(t, k) = [int(i) for i in input().split()]\\ns = t * k\\nif s % 2 == 0:\\n\\tprint(s // 2)\\nelse:\\n\\ts = s - 1\\n\\tprint(s // 2)\\n\",\n \"x = list(map(int, input().split()))\\npro1 = x[0] * x[1]\\nanf = pro1 // 2\\nprint(anf)\\n\",\n \"rint = lambda : int(input())\\nrmint = lambda : map(int, input().split())\\nrlist = lambda : list(rmint())\\n(n, m) = rmint()\\nprint(n * m // 2)\\n\",\n \"import math\\n(m, n) = input().split(' ')\\nsumat = int(m) * int(n)\\nprint(math.floor(sumat / 2))\\n\",\n \"(A, B) = map(int, input().split())\\nif (A and B) >= 1 and (A and B) <= 16:\\n\\tS = A * B\\n\\tif S % 2 == 0:\\n\\t\\tprint(int(S / 2))\\n\\tif S % 2 != 0:\\n\\t\\tprint(S // 2)\\n\",\n \"import math\\nimport os\\nimport random\\nimport re\\nimport sys\\n\\ndef solve():\\n\\t(m, n) = list(map(int, input().split()))\\n\\tarea = m * n\\n\\treturn math.floor(area / 2)\\nresult = solve()\\nprint(result)\\n\",\n \"(n, m) = map(lambda val: int(val), input().split())\\nprint(n * m // 2)\\n\",\n \"n = input().split()\\nn1 = int(n[0])\\nn2 = int(n[1])\\nx = n1 * n2\\nif x % 2 == 0:\\n\\tf = int(x / 2)\\nelse:\\n\\tf = int((x - 1) / 2)\\nprint(f)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nans = 0\\nif m > 1:\\n\\tremaining = m % 2\\n\\tans = n * (m // 2)\\n\\tif remaining == 1:\\n\\t\\tans += n // 2\\nelif n > 1:\\n\\tremaining = n % 2\\n\\tans = m * (n // 2)\\n\\tif remaining == 1:\\n\\t\\tans += m // 2\\nprint(ans)\\n\",\n \"(n, k) = [int(i) for i in input().split()]\\nz = n * k // 2\\nprint(z)\\n\",\n \"(m, n) = (int(i) for i in input().split())\\nif min(m, n) % 2 == 0:\\n\\tresult = m * n // 2\\nelse:\\n\\tresult = max(m, n) * (min(m, n) - 1) // 2 + max(m, n) // 2\\nprint(result)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\na = m // 2\\nr = m % 2\\nif r == 0:\\n\\tnum = a * n\\nelse:\\n\\tnum = a * n + n // 2\\nprint(num)\\n\",\n \"(x, y) = input().split()\\nn = int(x)\\nm = int(y)\\nif n % 2 == 0:\\n\\td = n // 2 * m\\nelse:\\n\\td = n // 2 * m + m // 2\\nprint(d)\\n\",\n \"(m, n) = map(int, input().split())\\nc = 2\\na = m * n\\nprint(int(a // c))\\n\",\n \"s = input()\\ns = s + ' '\\nif s[1] == ' ':\\n\\tM = int(s[0])\\n\\tif s[3] == ' ':\\n\\t\\tN = int(s[2])\\n\\telse:\\n\\t\\tN = int(s[2] + s[3])\\nelse:\\n\\tM = int(s[0] + s[1])\\n\\tif s[4] == ' ':\\n\\t\\tN = int(s[3])\\n\\telse:\\n\\t\\tN = int(s[3] + s[4])\\nif M % 2 == 0 or N % 2 == 0:\\n\\ta = int(M * N / 2)\\nelse:\\n\\ta = int((M * N - 1) / 2)\\nprint(a)\\n\",\n \"(m, n) = map(int, input().split())\\nif m >= 1 and n >= m and (n <= 16):\\n\\tif m >= 2:\\n\\t\\trow = m // 2\\n\\t\\tcol = n // 1\\n\\t\\ttotal = row * col\\n\\t\\tif m % 2 == 1:\\n\\t\\t\\ttotal = total + n // 2\\n\\t\\tprint(total)\\n\\tif m < 2:\\n\\t\\ttotal = n // 2\\n\\t\\tprint(total)\\n\",\n \"list1 = list(map(int, input().split()))\\nfinalval = 1\\nfor x in list1:\\n\\tfinalval *= x\\nprint(int(finalval / 2))\\n\",\n \"import sys\\n\\ndef max_count(n, m):\\n\\tif n % 2 == 0:\\n\\t\\tres = n // 2 * m\\n\\telif m % 2 == 0:\\n\\t\\tres = m // 2 * n\\n\\telse:\\n\\t\\tres = n * (m - 1) // 2 + (n - 1) // 2\\n\\treturn res\\ndata = list(map(int, sys.stdin.read().split()))\\n(n, m) = data[0:2]\\nprint(max_count(n, m))\\n\",\n \"domino_board_sizes = list((int(num) for num in input().split(' ')))\\nprint(int(domino_board_sizes[0] * domino_board_sizes[1] / 2))\\n\",\n \"area = input()\\nareaList = area.split(' ')\\ntotalArea = int(areaList[0]) * int(areaList[1])\\nprint(totalArea // 2)\\n\",\n \"def solve():\\n\\t(width, height) = str(input()).split()\\n\\t(width, height) = (int(width), int(height))\\n\\twide_box = width * height\\n\\twide_dom = 2 * 1\\n\\ttot_dom = int(wide_box / wide_dom)\\n\\tprint(tot_dom)\\nsolve()\\n\",\n \"size = input()\\nsize = size.split()\\nfor i in range(len(size)):\\n\\tsize[i] = int(size[i])\\nif size[0] % 2 == 0 and size[1] % 2 == 0:\\n\\tprint(size[0] // 2 * size[1])\\nelif size[0] % 2 == 0 or size[1] % 2 == 0:\\n\\tif size[0] % 2 == 0:\\n\\t\\tprint(size[0] // 2 * size[1])\\n\\telse:\\n\\t\\tprint(size[1] // 2 * size[0])\\nelse:\\n\\tprint(size[0] * size[1] // 2)\\n\",\n \"import math\\n(n, m) = map(int, input().split())\\nans = math.floor(n / 2) * m\\nif n % 2 != 0:\\n\\tans += math.floor(m / 2)\\nprint(ans)\\n\",\n \"from sys import stdin\\n_input = stdin.readline\\n_int = int\\n\\ndef solution():\\n\\t(n, m) = [_int(i) for i in _input().split()]\\n\\tif n == 1 and m == 1:\\n\\t\\tprint(0)\\n\\telif n % 2 == 0 or m % 2 == 0:\\n\\t\\tprint(n * m // 2)\\n\\telse:\\n\\t\\tprint(((n - 1) * (m - 1) + (n - 1) + (m - 1)) // 2)\\nsolution()\\n\",\n \"def dominos(m, n):\\n\\tif m % 2 == 0:\\n\\t\\treturn n * (m / 2)\\n\\telif n % 2 == 0:\\n\\t\\treturn m * (n / 2)\\n\\telse:\\n\\t\\tif m == 1 and n == 1:\\n\\t\\t\\treturn 0\\n\\t\\tif m == 1:\\n\\t\\t\\treturn n // 2\\n\\t\\tif n == 1:\\n\\t\\t\\treturn m // 2\\n\\t\\telse:\\n\\t\\t\\treturn (m - 1) / 2 * n + n // 2\\nimport sys\\nline = []\\nfor l in sys.stdin:\\n\\tline.append(l.rstrip('\\\\n'))\\n(m, n) = (int(line[0].split(' ')[0]), int(line[0].split(' ')[1]))\\nprint(int(dominos(m, n)))\\n\",\n \"params = input().split(' ')\\nprint(int(int(params[0]) * int(params[1]) / 2))\\n\",\n \"(n, m) = [int(s) for s in input().split()]\\na = n * m\\nprint(a // 2)\\n\",\n \"def dom(m, n):\\n\\tif m == 1 and n == 1:\\n\\t\\treturn 0\\n\\telse:\\n\\t\\ta1 = m * n\\n\\t\\tres = int(a1 / 2)\\n\\t\\treturn res\\n(m, n) = map(int, input().split())\\nprint(dom(m, n))\\n\",\n \"mn = input().split()\\nm = int(mn[0])\\nn = int(mn[1])\\nop = 0\\nif n > m:\\n\\ttemp = m\\n\\tm = n\\n\\tn = temp\\nif m % 2 != 0 and n % 2 != 0:\\n\\tif n == 1:\\n\\t\\top = (m - 1) / 2\\n\\telse:\\n\\t\\top = (n - 1) / 2 * m + int(m / 2)\\nelif m % 2 == 0:\\n\\top = m / 2 * n\\nelse:\\n\\top = n / 2 * m\\nprint(int(op))\\n\",\n \"def init(m, n):\\n\\tboard = []\\n\\tnew = []\\n\\tfor i in range(m):\\n\\t\\tfor j in range(n):\\n\\t\\t\\tnew.append(0)\\n\\t\\tboard.append(new)\\n\\t\\tnew = []\\n\\treturn board\\n\\ndef calculate(board, m, n):\\n\\tfilled = 0\\n\\tfor i in range(m):\\n\\t\\tfor j in range(n):\\n\\t\\t\\tif board[i][j] == 1:\\n\\t\\t\\t\\tpass\\n\\t\\t\\telif j + 1 != n:\\n\\t\\t\\t\\tif board[i][j + 1] == 0:\\n\\t\\t\\t\\t\\tboard[i][j] = 1\\n\\t\\t\\t\\t\\tboard[i][j + 1] = 1\\n\\t\\t\\t\\t\\tfilled += 1\\n\\t\\t\\telif i + 1 != m:\\n\\t\\t\\t\\tif board[i + 1][j] == 0:\\n\\t\\t\\t\\t\\tboard[i][j] = 1\\n\\t\\t\\t\\t\\tboard[i + 1][j] = 1\\n\\t\\t\\t\\t\\tfilled += 1\\n\\treturn filled\\n\\ndef main():\\n\\tinputstring = input()\\n\\tm = int(inputstring.split()[0])\\n\\tn = int(inputstring.split()[1])\\n\\tboard = init(m, n)\\n\\tprint(calculate(board, m, n))\\nmain()\\n\",\n \"userInput = input()\\ninputs = userInput.split()\\nm = int(inputs[0])\\nn = int(inputs[1])\\nans = 0\\nif n % 2 == 0:\\n\\tans = n // 2 * m\\nelse:\\n\\tans = n // 2 * m + m // 2\\nprint(str(ans))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m * n % 2 == 0:\\n\\tamount = m * n / 2\\nelse:\\n\\tamount = (m * n - 1) / 2\\namount = int(amount)\\nprint(amount)\\n\",\n \"(m, n) = map(int, input().split())\\nans = m // 2 * n\\nif m % 2 != 0:\\n\\tans += n // 2\\nprint(ans)\\n\",\n \"import math\\nnum = str(input())\\nnum = [int(j) for j in num.split()]\\nm = num[0]\\nn = num[1]\\nans = int(n * math.floor(m / 2))\\nif m % 2 != 0:\\n\\tans = int(ans + math.floor(n / 2))\\nprint(ans)\\n\",\n \"(M, N) = map(int, input().split())\\nnum = 0\\narea = M * N\\nwhile area > 1:\\n\\tarea -= 2\\n\\tnum += 1\\nprint(num)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nf = n * (m // 2) + n // 2 * (m % 2)\\nprint(f)\\n\",\n \"str = input()\\nstr = str.split(' ')\\nM = int(str[0])\\nN = int(str[1])\\nprint(int(M * N) // 2)\\n\",\n \"import math\\n(x, y) = [int(i) for i in input().split()]\\nanswer = x * y / 2\\nprint(math.floor(answer))\\n\",\n \"board_size = list(map(int, input().split()))\\na = board_size[0]\\nb = board_size[1]\\nprint(int(a * b / 2))\\n\",\n \"(rows, columns) = map(int, input().split())\\nrem1 = rows % 2\\ndominos1 = rows // 2 * columns + rem1 * columns // 2\\nrem1 = columns % 2\\ndominos2 = columns // 2 * rows + rem1 * rows // 2\\nif dominos1 > dominos2:\\n\\tprint(dominos1)\\nelse:\\n\\tprint(dominos2)\\n\",\n \"l = input()\\nli = l.split(' ')\\nm = int(li[0])\\nn = int(li[1])\\nif m == 1:\\n\\tprint(int(n / 2))\\nelif n == 1:\\n\\tprint(int(m / 2))\\nelif m % 2 == 0 and m > 1:\\n\\tprint(int(m / 2 * n))\\nelif n % 2 == 0 and m > 1:\\n\\tprint(int(n / 2 * m))\\nelif m % 2 != 0 and n % 2 != 0 and (m > 1) and (n > 1):\\n\\tprint(int((int(n / 2) * 2 + 1) * int(m / 2) + int(n / 2)))\\n\",\n \"def solution(n, m, ans):\\n\\tif n * m < 2:\\n\\t\\treturn ans\\n\\tif n >= m:\\n\\t\\treturn solution(n - 2, m, ans + m)\\n\\telse:\\n\\t\\treturn solution(n, m - 2, ans + n)\\nnm = input().split(' ')\\nn = int(nm[0])\\nm = int(nm[1])\\nans = solution(n, m, 0)\\nprint(ans)\\n\",\n \"import sys\\nimport math\\nparameters = sys.stdin.readline().rstrip().split(' ')\\nparam1 = int(parameters[0])\\nparam2 = int(parameters[1])\\nif param1 > param2:\\n\\twidth = param1\\n\\theight = param2\\nelse:\\n\\twidth = param2\\n\\theight = param1\\ndominosWide = width // 2\\ntotalDominos = dominosWide * height\\nif width % 2 == 1:\\n\\ttotalDominos += height // 2\\nprint(totalDominos)\\n\",\n \"i = input()\\ni = i.split(' ')\\nm = int(i[0])\\nn = int(i[1])\\narea = m * n\\ncount = 0\\nif area % 2 != 0 and area != 0:\\n\\tarea -= 1\\nprint(int(area / 2))\\n\",\n \"(a, b) = input().split()\\nm = int(a)\\nn = int(b)\\nans = m * n / 2\\nprint(int(ans))\\n\",\n \"mn = list(map(int, input().split()))\\nM = mn[0]\\nN = mn[1]\\nif M > N:\\n\\tprint(int(M * N / 2))\\nelse:\\n\\tprint(int(N * M / 2))\\n\",\n \"x = list(map(int, input().rstrip().split()))\\nans = x[0] * x[1]\\nprint(ans // 2)\\n\",\n \"(n, m) = map(int, input().split())\\nif not n % 2:\\n\\tprint(m * (n // 2))\\nelif not m % 2:\\n\\tprint(n * (m // 2))\\nelse:\\n\\tprint(int(n / 2 * m))\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nanswer = m * n / 2\\nanswer = int(answer)\\nprint(answer)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\narea = a * b\\nif area % 2 == 0:\\n\\tw = int(area / 2)\\n\\tprint(w)\\nelse:\\n\\tarea -= 1\\n\\td = int(area / 2)\\n\\tprint(d)\\n\",\n \"l = input().split()\\na = int(l[0])\\nb = int(l[1])\\nc = a * b\\nprint(int(c // 2))\\n\",\n \"numbers = [int(d) for d in input().split(' ')]\\nn = numbers[0]\\nm = numbers[1]\\nsize = n * m\\nif n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tpart1 = m * (n - 1) / 2\\n\\tif m % 2 == 0:\\n\\t\\tpart1 += m / 2\\n\\telse:\\n\\t\\tpart1 += (m - 1) / 2\\n\\tprint(int(part1))\\n\",\n \"(x, y) = [int(x) for x in input().split()]\\narea = x * y\\na = area // 2\\nprint(a)\\n\",\n \"(M, N) = map(int, input().split())\\nif M % 2 == 0:\\n\\tprint(M // 2 * N)\\nif M % 2 != 0:\\n\\tprint(M // 2 * N + N // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0 or n % 2 == 0:\\n\\tnum = n * m * 0.5\\nelse:\\n\\tnum = (n * m - 1) * 0.5\\nprint(int(num))\\n\",\n \"L = input().split()\\nm = int(L[0])\\nn = int(L[1])\\nprint(m * n // 2)\\n\",\n \"(m, n) = [int(k) for k in input().split()]\\nprint(m * n // 2)\\n\",\n \"(l, b) = map(int, input().split())\\ntotalSquare = l * b\\nif totalSquare % 2 != 0:\\n\\ttotalSquare -= 1\\nans = totalSquare / 2\\nprint(round(ans))\\n\",\n \"product = 1\\nx = list(map(int, input().split()))\\nfor item in x:\\n\\tproduct = product * item\\nprint(product // 2)\\n\",\n \"import copy\\n(n, m) = list(map(int, input().split(' ')))\\nans = n * m // 2\\nprint(ans)\\n\",\n \"(l, s) = input().split(' ')\\nl = int(l)\\ns = int(s)\\nmultiple = l * s\\nprint(int(multiple / 2))\\n\",\n \"def dominoPiling(mn):\\n\\tprint(int(mn[0] * mn[1] / 2))\\ndominoPiling(list(map(int, input().split())))\\n\",\n \"import sys\\n(a, b) = map(int, sys.stdin.readline().split())\\narea = a * b\\nprint(area // 2)\\n\",\n \"def main():\\n\\t(m, n) = [int(i) for i in input().split()]\\n\\tcolumns = m // 2\\n\\tright_pad_empty = m % 2\\n\\trows = n\\n\\tnow = rows * columns\\n\\tif right_pad_empty:\\n\\t\\tnow += rows // 2\\n\\tprint(now)\\nmain()\\n\",\n \"board = input()\\nboard_list = board.split()\\narea = int(board_list[0]) * int(board_list[1])\\ndomino_fit = int(area / 2)\\nprint(domino_fit)\\n\",\n \"(m, n) = map(int, input().split())\\ni = 0\\nif m == 1 or n == 1:\\n\\tj = max(m, n)\\n\\tnumber = j // 2\\nelif n % 2 != 0:\\n\\tnumber = m * (n // 2) + m // 2\\nelse:\\n\\tnumber = m * (n // 2)\\nprint(number)\\n\",\n \"(a, b) = (int(x) for x in input().split(' '))\\nif a % 2 == 0:\\n\\ta = a / 2\\n\\tc = a * b\\nelif b % 2 == 0:\\n\\tb = b / 2\\n\\tc = a * b\\nelse:\\n\\tc = (a - 1) / 2 * b + (b - 1) / 2\\nc = int(c)\\nprint(c)\\n\",\n \"a = list(map(int, input().split()))\\nc = a[0]\\nm = a[1]\\nv = c * m\\nj = v // 2\\nprint(j)\\n\",\n \"b = list(map(int, input().split()))\\na = b[0] * b[1] / 2\\nprint(str(int(a)))\\n\",\n \"import sys\\n\\ndef calc(n, m):\\n\\treturn n // 2 * m + n % 2 * (m // 2)\\n(m, n) = map(int, sys.stdin.readline().split())\\nprint(max(calc(n, m), calc(m, n)))\\n\",\n \"(n, m) = map(int, input().split())\\nres = divmod(n * m, 2)\\nprint(res[0])\\n\",\n \"l = list(input().split())\\nsqa = int(l[0]) * int(l[1])\\nsqa = sqa // 2\\nprint(sqa)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\ntiles = area // 2\\nprint(tiles)\\n\",\n \"base_input = input()\\nsize_input = base_input.split(' ')\\nmax_dominos = int(int(size_input[0]) * int(size_input[1]) / 2)\\nprint(max_dominos)\\n\",\n \"(n, k) = list(map(int, input().split()))\\nprint(int(n * k / 2))\\n\",\n \"inputs = list(map(int, input().strip().split()))[:2]\\nm = inputs[0]\\nn = inputs[1]\\no = 0\\nwhile True:\\n\\tif m <= 0:\\n\\t\\tbreak\\n\\telif m < 2:\\n\\t\\to += int(n / 2)\\n\\t\\tm -= 1\\n\\telse:\\n\\t\\to += n\\n\\t\\tm -= 2\\nprint(o)\\n\",\n \"(M, N) = map(int, input().split())\\narea = M * N\\nans = 0\\nif N % 2 == 0 and M % 2 == 0:\\n\\tans = area // 2\\nelif N % 2 == 0 and M % 2 != 0 or (N % 2 != 0 and M % 2 == 0):\\n\\tans = area // 2\\nelse:\\n\\tans = area // 2\\nprint(ans)\\n\",\n \"class DominoPiling:\\n\\n\\t@staticmethod\\n\\tdef solve(x, y):\\n\\t\\tunit = 2 * 1\\n\\t\\tif 1 <= x <= y <= 16:\\n\\t\\t\\treturn '%d' % (x * y / unit)\\n\\ndef main():\\n\\t(x, y) = list(map(int, input().split(' ')))\\n\\tdp = DominoPiling()\\n\\tprint(dp.solve(x, y))\\nmain()\\n\",\n \"import sys\\n\\ndef domino_calc(m, n):\\n\\tarea = m * n\\n\\tif area % 2 == 0:\\n\\t\\treturn area / 2\\n\\treturn (area - 1) / 2\\ninputs = [int(x) for x in input().split()]\\ndominos = domino_calc(inputs[0], inputs[1])\\nprint('%d' % dominos)\\n\",\n \"(m, n) = map(int, input().split())\\nx = 1\\nwhile 2 * x <= m * n:\\n\\tx += 1\\nprint(x - 1)\\n\",\n \"(M, N) = map(int, input().split())\\nimport math\\nif M % 2 == 1 and N % 2 == 1:\\n\\tprint(math.floor(M * N / 2))\\nelse:\\n\\tprint(int(M * N / 2))\\n\",\n \"nm = list(map(int, input().split()))\\nr = nm[0] * nm[1]\\np = int(r / 2)\\nprint(p)\\n\",\n \"x = input()\\nx = x.split()\\nm = int(x[0])\\nn = int(x[1])\\nres = m * (n // 2) + n % 2 * (m // 2)\\nprint(res)\\n\",\n \"import os\\nimport sys\\ndebug = True\\nif debug and os.path.exists('input.in'):\\n\\tinput = open('input.in', 'r').readline\\nelse:\\n\\tdebug = False\\n\\tinput = sys.stdin.readline\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef insr():\\n\\ts = input()\\n\\treturn s[:len(s) - 1]\\n\\ndef invr():\\n\\treturn map(int, input().split())\\ntest_count = 1\\nif debug:\\n\\ttest_count = inp()\\nfor t in range(test_count):\\n\\tif debug:\\n\\t\\tprint('Test Case #', t + 1)\\n\\t(m, n) = invr()\\n\\tprint(m * n // 2)\\n\",\n \"from math import floor as f\\n(m, n) = map(int, input().split())\\nprint(f(m * n / 2))\\n\",\n \"from functools import reduce\\nmaximal = reduce(lambda x, y: x * y, [int(x) for x in str(input()).split(' ')])\\nprint(maximal // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nif 1 <= m <= 16 and 1 <= n <= 16:\\n\\tarear = m * n\\n\\tx = arear / 2\\n\\tprint(int(x))\\n\",\n \"(M, N) = map(int, input().split())\\nArea_of_rect = M * N\\nM_N_D = Area_of_rect // 2\\nprint(M_N_D)\\n\",\n \"import math\\nline = input().split()\\nnum = int(line[0]) * int(line[1]) // 2\\nprint(num)\\n\",\n \"import math\\nlis = list(map(int, input().split()))\\nm = lis[0]\\nn = lis[1]\\nres = math.floor(m / 2 * n)\\nprint(res)\\n\",\n \"def sol(n, k):\\n\\tt = 2 * 1\\n\\tb = n * k\\n\\treturn b / t\\n(n, k) = map(int, input().split(' '))\\nprint(int(sol(n, k)))\\n\",\n \"import math\\nline = input().split()\\nM = int(line[0])\\nN = int(line[1])\\ntotal = math.floor(M / 2) * N + M % 2 * math.floor(N / 2)\\nprint(total)\\n\",\n \"import math\\nall = [int(i) for i in input().split()]\\narea = all[0] * all[1]\\nprint(math.floor(area / 2))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 1 and n % 2 == 1:\\n\\tc = (m * n - 1) // 2\\nelse:\\n\\tc = m * n // 2\\nprint(c)\\n\",\n \"buf = input().split(' ')\\na = int(buf[0])\\nb = int(buf[1])\\nprint(a * b // 2)\\n\",\n \"(m, n) = map(int, input().split())\\na = n // 2\\nb = n % 2\\np = b * m\\nc = p // 2\\nprint(a * m + c)\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\nprint(math.floor(a * b * 0.5))\\n\",\n \"s = input()\\nmn = s.split()\\nm = int(mn[0])\\nn = int(mn[1])\\nans = int(m * n / 2)\\nprint(ans)\\n\",\n \"def main():\\n\\t(M, N) = map(int, input().split(' '))\\n\\tn = M * N // 2\\n\\tprint(n)\\nmain()\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\nimport math\\nsize = inlt()\\nm = size[0]\\nn = size[1]\\nprint(int(math.floor(n * m * 0.5)))\\n\",\n \"(m, n) = map(int, input().split())\\nc = 0\\nif m % 2 != 0:\\n\\tn_r = m - 1\\nelse:\\n\\tn_r = m\\nfor i in range(0, n_r, 2):\\n\\tc += 1\\nc = c * n\\nn_C = m - n_r\\nc2 = 0\\nif n % 2 != 0:\\n\\tn_c = n - 1\\nelse:\\n\\tn_c = n\\nfor i in range(0, n_c, 2):\\n\\tc2 += 1\\nc = c + c2 * n_C\\nprint(c)\\n\",\n \"s = input()\\nn = [int(i) for i in s.split(' ')]\\nn1 = min(n)\\nn2 = max(n)\\nc = n1 // 2 * n2\\nif n1 % 2 == 1:\\n\\tc = c + n2 // 2\\nprint(int(c))\\n\",\n \"(a, b) = map(int, input().split())\\nif a / 2 == a // 2:\\n\\tanswer = a / 2 * b\\nelif b / 2 == b // 2:\\n\\tanswer = (a - 1) // 2 * b + b // 2\\nelse:\\n\\tanswer = (a - 1) // 2 * b + (b - 1) // 2\\nanswer1 = int(answer)\\nprint(answer1)\\n\",\n \"l = input().split()\\nM = int(l[0])\\nN = int(l[1])\\nif M % 2 != 0 and N % 2 != 0:\\n\\tn = M * int(N / 2) + int(M / 2)\\nelse:\\n\\tn = int(M * N / 2)\\nprint(n)\\n\",\n \"import sys\\n(n, m) = [int(x) for x in input().split(' ')]\\nif n % 2 == 0:\\n\\tjavob = int(n / 2 * m)\\nelse:\\n\\tjavob = int(n / 2) * m + int(m / 2)\\nprint(javob)\\n\",\n \"def go(a, b):\\n\\treturn a * b // 2\\n(a, b) = list(map(int, input().split(' ')))\\nprint(go(a, b))\\n\",\n \"give = input()\\na = give.split()\\nM = int(a[0])\\nN = int(a[1])\\nif M * N % 2 == 0:\\n\\tprint(int(M * N / 2))\\nelse:\\n\\tprint(int((M * N - 1) / 2))\\n\",\n \"(M, N) = [int(x) for x in input().split(' ', 1)]\\nif M == 1:\\n\\tsum = N // 2\\nelif M % 2 == 0:\\n\\tsum = N * M // 2\\nelse:\\n\\tsum = N * (M // 2) + N // 2\\nprint(sum)\\n\",\n \"x = input('')\\nx = x.split()\\nx = [int(i) for i in x]\\nn = x[0]\\nm = x[-1]\\nextra = 0\\nif m % 2 == 0:\\n\\tusex = m\\n\\tusey = n\\nelse:\\n\\tusex = m - 1\\n\\tusey = n\\n\\tif n % 2 == 0:\\n\\t\\textra += n\\n\\telse:\\n\\t\\textra += n - 1\\nprint(int((usex * usey + extra) / 2))\\n\",\n \"def main():\\n\\tstr = input().split()\\n\\tM = int(str[0])\\n\\tN = int(str[1])\\n\\tboard_size = M * N\\n\\tdomino_number = board_size // 2\\n\\tprint(domino_number)\\nmain()\\n\",\n \"from math import floor\\narr = list(map(int, input().strip().split()))\\nl = 2\\nb = 1\\nle = 0\\nbr = 0\\nmaxa = max(arr)\\nmina = min(arr)\\nif maxa >= l:\\n\\tprint(floor(maxa * mina / l * b))\\nelse:\\n\\tprint(0)\\n\",\n \"import math\\n\\ndef gcd(a, b):\\n\\tif a % b == 0:\\n\\t\\treturn b\\n\\telse:\\n\\t\\treturn gcd(b, a % b)\\n\\ndef main():\\n\\t(m, n) = map(int, input().split(' '))\\n\\tprint(math.floor(m * n / 2))\\nmain()\\n\",\n \"import sys\\n\\ndef get_ints():\\n\\treturn list(map(int, sys.stdin.readline().strip().split()))\\nArr = get_ints()\\nprint(int(Arr[0] * Arr[1] / 2))\\n\",\n \"mn = list(map(int, input().split()))\\nm = mn[0]\\nn = mn[1]\\narea = m * n\\nb = area // 2\\nprint(b)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\na = m * n\\nif a % 2 == 1:\\n\\tb = (a - 1) / 2\\nelse:\\n\\tb = a / 2\\nb = int(b)\\nprint(str(b))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nv = m % 2\\nw = n % 2\\nif v == 0 and w == 0:\\n\\ts = m * (n // 2)\\nelif v == 0:\\n\\ts = m * (n // 2) + m // 2\\nelif w == 0:\\n\\ts = n * (m // 2) + n // 2\\nelse:\\n\\ts = (m - 1) * (n // 2) + n // 2 + m // 2\\nprint(s)\\n\",\n \"from math import floor\\n(m, n) = map(int, input().split(' '))\\nresult = floor(m * n / 2)\\nprint(result)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nans = area // 2\\nprint(ans)\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\nif a * b % 2 == 0:\\n\\tm = a * b / 2\\nelse:\\n\\tm = (a * b - 1) / 2\\nprint(int(m))\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\ns = b * a\\notv = s // 2\\nprint(otv)\\n\",\n \"(m, n) = map(int, input().split())\\nv = m * n\\nb = 0\\nc = 0\\nwhile v >= b:\\n\\tb = b + 2\\n\\tif b <= v:\\n\\t\\tc = c + 1\\nprint(c)\\n\",\n \"board = input()\\nboardList = board.split(' ')\\n(M, N) = (boardList[0], boardList[1])\\ntotal_board_size = int(M) * int(N)\\nif total_board_size % 2 == 0:\\n\\toutput = total_board_size / 2\\nelse:\\n\\toutput = (total_board_size - 1) / 2\\nprint(int(output))\\n\",\n \"var = input()\\narea = int(var.split()[0]) * int(var.split()[1])\\na = area % 2\\nprint(int((area - a) / 2))\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\ns = n * m\\nq = s // 2\\nprint(q)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\nr = 2 * 1\\nif s % r == 0:\\n\\tprint(s // r)\\nelse:\\n\\to = s // r\\n\\tprint(o)\\n\",\n \"input_string = input()\\nM = int(input_string.split()[0])\\nN = int(input_string.split()[1])\\nprint(M * N // 2)\\n\",\n \"(n, m) = map(int, input().split(' '))\\ntotal = n * m\\ndominos = int(total / 2)\\nprint(dominos)\\n\",\n \"import math\\nimport sys\\nfrom functools import reduce\\nfrom operator import mul\\ninf = sys.stdin\\ntemp = inf.readline()\\nsize = [int(i) for i in temp.split(' ')]\\nproduct = reduce(mul, size, 1)\\nprint(math.floor(product / 2))\\n\",\n \"nums = input().split()\\nprint(int(int(nums[0]) * int(nums[1]) / 2))\\n\",\n \"a = input()\\naa = [int(k) for k in a.split(' ')]\\nploschad = aa[0] * aa[1]\\nskolko = ploschad // 2\\nprint(skolko)\\n\",\n \"stream = input().split(' ')\\nm = int(stream[0])\\nn = int(stream[1])\\nprint(m * n // 2)\\n\",\n \"(n, m) = tuple([int(num) for num in input().split()])\\nif n % 2 == 0 or m % 2 == 0:\\n\\tprint(n * m // 2)\\nelse:\\n\\tprint(n * (m - 1) // 2 + n // 2)\\n\",\n \"string = input()\\nm = int(string.split()[0])\\nn = int(string.split()[1])\\nif m * n % 2 == 1:\\n\\tprint(int(m * n / 2 - 0.5))\\nelse:\\n\\tprint(int(m * n / 2))\\n\",\n \"h = tuple(map(int, input().split()))\\nprint(h[0] * h[1] // 2)\\n\",\n \"m = input()\\nm = m.split()\\nprint(int(m[0]) * int(m[1]) // 2)\\n\",\n \"def input_int(sep=' '):\\n\\trst = [int(n) for n in input().split(sep) if n]\\n\\treturn rst\\n(M, N) = input_int()\\nif M == 1:\\n\\tprint(int(N / 2))\\nelif M % 2 == 0:\\n\\tprint(int(M / 2) * N)\\nelse:\\n\\tprint(int(M / 2) * N + int(N / 2))\\n\",\n \"n = list(map(int, input().split()))\\nif n[0] == 1 and n[1] == 1:\\n\\tprint('0')\\nelse:\\n\\ts = n[0] * n[1]\\n\\tm = 0\\n\\tfor i in range(s):\\n\\t\\tk = s - 2\\n\\t\\ts = k\\n\\t\\tm = m + 1\\n\\t\\tif s <= 1:\\n\\t\\t\\tprint(m)\\n\\t\\t\\tbreak\\n\",\n \"def ii():\\n\\treturn int(input())\\n\\ndef si():\\n\\treturn input()\\n\\ndef mi():\\n\\treturn map(int, input().split())\\n\\ndef li():\\n\\treturn list(mi())\\n(n, m) = mi()\\nif n == 1 and m == 1:\\n\\tprint('0')\\nelif n == 1 and m == 2 or (m == 1 and n == 2):\\n\\tprint('1')\\nelse:\\n\\tx = n // 2\\n\\tans = x * m\\n\\tif n % 2:\\n\\t\\tans += m // 2\\n\\tprint(ans)\\n\",\n \"(n1, n2) = map(int, input().split())\\nresult = n1 * n2\\nprint(result // 2)\\n\",\n \"a = input()\\nad = 2 * 1\\nb = a.split()\\nc = 0\\nfor i in b:\\n\\tc = int(b[0]) * int(b[1])\\nd = c // ad\\nprint(d)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nx = m * n\\nif x % 2 != 0:\\n\\tx = x - 1\\n\\ty = x / 2\\n\\tprint(int(y))\\nelse:\\n\\ty = x / 2\\n\\tprint(int(y))\\n\",\n \"(m, n) = [int(x) for x in input('').split(' ')]\\nproduct = m * n\\nmax = product // 2\\nprint(max)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nif area < 2:\\n\\tout = 0\\nelif area == 2:\\n\\tout = 1\\nelse:\\n\\tlower_bound = m // 2 * (n // 2)\\n\\tadditional_count = (m * n - lower_bound * 4) // 2\\n\\tout = lower_bound * 2 + additional_count\\nprint(out)\\n\",\n \"inp = input()\\n(m, n) = list(map(int, inp.split(' ')))\\nsquare = n * m\\nprint(square // 2)\\n\",\n \"from math import floor\\n(m, n) = map(int, input().split())\\ndominos = floor(n / 2) * m\\nif n % 2:\\n\\tdominos += floor(m / 2)\\nprint(dominos)\\n\",\n \"arr = list(map(int, input().strip().split()))\\nm = arr[0] * arr[1]\\nt = m // 2\\nprint(t)\\n\",\n \"(m, n) = map(int, input().split())\\nx = max(m, n)\\ny = min(m, n)\\nprint(x * (y // 2) + y % 2 * (x // 2))\\n\",\n \"(m, n) = map(int, input().split())\\np = m * n\\noutput = 0\\nif p % 2 == 1:\\n\\toutput += (p - 1) // 2\\nelse:\\n\\toutput += p // 2\\nprint(output)\\n\",\n \"import math\\nline = input()\\n(m, n) = line.split()\\nm = int(m)\\nn = int(n)\\nif m % 2 != 0:\\n\\ta = math.floor(m / 2) * n + math.floor(n / 2)\\nelse:\\n\\ta = m * n / 2\\nprint(int(a))\\n\",\n \"while True:\\n\\t(n, m) = map(int, input().split(' '))\\n\\tif n and m in range(1, 17):\\n\\t\\tbreak\\nprint(int(n * m / 2))\\n\",\n \"def domino_piling(m, n):\\n\\tif m % 2 == 1 and n % 2 == 1:\\n\\t\\treturn (m * n - 1) // 2\\n\\telse:\\n\\t\\treturn m * n // 2\\n(m, n) = (int(x) for x in input().split(' '))\\nprint(domino_piling(m, n))\\n\",\n \"n = input().split()\\nn = list(map(int, n))\\nprint(str(int(n[0] * n[1] / 2)))\\n\",\n \"n = input().split()\\nn = [int(i) for i in n]\\np = n[0] * n[1]\\nprint(p // 2, end='')\\n\",\n \"(area, area2) = input().split()\\narea = int(area)\\narea2 = int(area2)\\nfinal_area = area * area2\\ndominos = 2\\nused = final_area // dominos\\nprint(used)\\n\",\n \"a = list(map(lambda x: int(x), input().split()))\\nprint(a[0] * a[1] // 2)\\n\",\n \"import math\\nnum = [int(x) for x in input().split()]\\nif num[0] > num[1]:\\n\\t(l, h) = (num[0], num[1])\\nelse:\\n\\t(l, h) = (num[1], num[0])\\nif l % 2 == 0:\\n\\tprint(h * l // 2)\\nelse:\\n\\tprint(h * (l // 2) + h // 2)\\n\",\n \"a = list(map(int, input().split()))\\nans = a[0] * a[1]\\nans = int(ans)\\nif ans % 2 == 0:\\n\\tprint(int(ans / 2))\\nelse:\\n\\tprint(int((ans - 1) / 2))\\n\",\n \"def count(m, n):\\n\\treturn int(m * n / 2)\\n(m, n) = input().split()\\nprint(count(int(m), int(n)))\\n\",\n \"def board(m, n):\\n\\tif m == 2:\\n\\t\\treturn n\\n\\telif n == 2:\\n\\t\\treturn m\\n\\telse:\\n\\t\\treturn m * n // 2\\n(m, n) = map(int, input().split())\\nprint(board(m, n))\\n\",\n \"s = input('').split()\\nm = int(s[0])\\nn = int(s[1])\\nmono = m * n\\ndominoes = m * n // 2\\nprint(dominoes)\\n\",\n \"def solve():\\n\\t(m, n) = list(map(int, input().split()))\\n\\tprint(m * n // 2)\\n\\ndef main():\\n\\tsolve()\\nmain()\\n\",\n \"(l, m) = map(int, input().split(' '))\\nfield = l * m\\nif field % 2 != 0:\\n\\tfield -= 1\\nprint(int(field / 2))\\n\",\n \"inp = input().split(' ')\\nArea = int(inp[0]) * int(inp[1])\\nnum = Area // 2\\nprint(num)\\n\",\n \"(M, N) = map(int, input().split())\\nrem = M * N % 2\\nif rem == 0:\\n\\tprint(M * N // 2)\\nelse:\\n\\tprint((M * N - rem) // 2)\\n\",\n \"L = input()\\nL = L.split()\\nM = int(L[0])\\nN = int(L[1])\\nT = N // 2\\nP = M // 2\\nif N % 2 == 0:\\n\\tR = T * M\\nelse:\\n\\tR = T * M + P\\nprint(R)\\n\",\n \"import sys\\ninput = sys.stdin.readline\\nnums = list(map(int, input().split()))\\narea = nums[0] * nums[1]\\nresult = int((area - area % 2) / 2)\\nprint(result)\\n\",\n \"mn = list(map(int, input().split()))\\nprint(mn[0] * mn[1] // 2)\\n\",\n \"def getDominoCount(width, height):\\n\\treturn width * height // 2\\n(a, b) = map(int, input().split(' '))\\nprint(getDominoCount(a, b))\\n\",\n \"sizes = [int(i) for i in input().split()]\\nprint(int(sizes[0] * sizes[1] / 2))\\n\",\n \"line = input()\\nM = int(line.split(' ')[0])\\nN = int(line.split(' ')[1])\\nsum = 0\\nif M % 2 == 0:\\n\\tsum = int(M * N / 2)\\nelse:\\n\\tM = M - 1\\n\\tsum = int(M * N / 2)\\n\\tsum = sum + int(N / 2)\\nprint(sum)\\n\",\n \"(n, m) = map(int, input().split())\\n\\ndef fun():\\n\\ta = n * m\\n\\tb = n * m / 2\\n\\treturn int(b)\\nprint(fun())\\n\",\n \"y = input()\\ny = y.split()\\nx = []\\nfor i in range(0, len(y)):\\n\\tm = int(y[i])\\n\\tx.append(m)\\nn = 1\\nfor j in range(0, len(x)):\\n\\tn = n * x[j]\\nn = n / 2\\nprint(int(n))\\n\",\n \"t = list(map(int, input().split(' ')))\\nm = t[0]\\nn = t[1]\\nresult = 0\\nresult = n // 2 * m\\nif n % 2 == 1:\\n\\tresult += m // 2\\nprint(result)\\n\",\n \"areainput = input()\\nx = areainput.split()\\narea = int(x[0]) * int(x[1])\\noutput = area // 2\\nprint(output)\\n\",\n \"(M, N) = map(int, input().split())\\nA = 0\\nA = M / 2 * N\\nprint(int(A))\\n\",\n \"area_input = input().split()\\narea = int(area_input[0]) * int(area_input[1])\\nif area % 2 == 0:\\n\\tprint(int(area / 2))\\nelse:\\n\\tprint(int(area / 2 - 0.5))\\n\",\n \"MN = input()\\nMN = MN.split()\\nM = int(MN[0])\\nN = int(MN[1])\\nif M % 2 == 0 or N % 2 == 0:\\n\\ttotal = M * N / 2\\nelse:\\n\\ttotal = (M - 1) * (N - 1) / 2\\n\\ttotal = total + (M + N - 1) / 2\\nprint(int(total))\\n\",\n \"(M, N) = list(map(int, input().split()))\\nCount = 0\\nwhile N >= 2:\\n\\tCount += M\\n\\tN -= 2\\nif N == 1:\\n\\tCount += int(M / 2)\\nprint(Count)\\n\",\n \"import math\\nline = input()\\npieces = line.split()\\na0 = int(pieces[0])\\na1 = int(pieces[1])\\nprint(int(a1 * a0 / 2))\\n\",\n \"import math\\n(m, n) = input().split(' ')\\n(m, n) = (int(m), int(n))\\ntotal = m * n\\ni = 0\\nresult = 0\\nfor i in range(9999):\\n\\tif 2 * i > total:\\n\\t\\tresult = i - 1\\n\\t\\tbreak\\nprint(result)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nres = 0\\nif m % 2 == 0 & n % 2 == 0:\\n\\tres = m / 2 * n\\nif m % 2 != 0 & n % 2 == 0:\\n\\tres = n / 2 * m\\nif m % 2 == 0 & n % 2 != 0:\\n\\tres = m / 2 * n\\nif m % 2 != 0 & n % 2 != 0:\\n\\tres = (m * n - 1) / 2\\nprint(int(res))\\n\",\n \"(a, b) = map(int, input().split(' '))\\nsuma = 0\\nr = a % 2\\nt = a // 2\\nt = t * b\\nsuma += t\\nif r == 1:\\n\\tsuma += b // 2\\nprint(suma)\\n\",\n \"import math\\nimport sys\\ninp = list(map(int, input().split()))\\nn = inp[0]\\nm = inp[1]\\nif n * m % 2 == 0:\\n\\tprint(round(n * m / 2))\\nelse:\\n\\tprint(round((n * m - 1) / 2))\\n\",\n \"l = input()\\nl = l.split()\\na = int(l[0])\\nb = int(l[1])\\nx = int(a * b / 2)\\nif a * b == 1:\\n\\tx = 0\\nprint(x)\\n\",\n \"mn = tuple(map(int, input().split()))\\nprint(int(mn[0] * mn[1] / 2))\\n\",\n \"(m, n) = input().split(' ')\\nwidth = int(m)\\nheight = int(n)\\nisArea = width * height\\nnumOfDomino = isArea // 2\\nprint(numOfDomino)\\n\",\n \"(m, n) = map(int, input().split())\\ntemp = 0\\nprint(m * n // 2)\\n\",\n \"i = input().split(' ')\\nif int(i[1]) % 2 == 0:\\n\\tprint(str(int(int(i[1]) / 2 * int(i[0]))))\\nelse:\\n\\tprint(str(int((int(i[1]) - 1) / 2 * int(i[0]) + (int(i[0]) - int(i[0]) % 2) / 2)))\\n\",\n \"m_and_n = input().split()\\nm = int(m_and_n[0])\\nn = int(m_and_n[1])\\ne = []\\nprint(m * n // 2)\\n\",\n \"(n, m) = map(int, input().rstrip().split())\\narea = n * m\\nprint(n * m // 2)\\n\",\n \"info = input().split(' ')\\nM = int(info[0])\\nN = int(info[1])\\nif M == N:\\n\\twidth = height = M\\nelif M < N:\\n\\theight = M\\n\\twidth = N\\nelse:\\n\\theight = N\\n\\twidth = M\\nanswer = 0\\nif height >= 2:\\n\\tanswer = height // 2 * width + height % 2 * (width // 2)\\nelse:\\n\\tanswer = width // 2\\nprint(answer)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ncount = n // 2\\ncount *= m\\nif n % 2 != 0:\\n\\tcount += m // 2\\nprint(count)\\n\",\n \"s = list(map(int, input().split()))\\nif s[0] % 2 == 0 or s[1] % 2 == 0:\\n\\tprint(s[0] * s[1] // 2)\\nelse:\\n\\tprint((s[0] * s[1] - 1) // 2)\\n\",\n \"def input_int():\\n\\treturn int(input())\\n\\ndef input_str():\\n\\treturn str(input())\\n\\ndef get_result(a, b):\\n\\treturn int(a * b / 2)\\n(a, b) = map(int, input().split())\\nprint(get_result(a, b))\\n\",\n \"def main():\\n\\t(m, n) = input().split()\\n\\tm = int(m)\\n\\tn = int(n)\\n\\tk = m * n\\n\\tif k % 2 == 0:\\n\\t\\ta = k / 2\\n\\t\\ta = int(a)\\n\\t\\tprint(a)\\n\\telse:\\n\\t\\ta = (k - 1) / 2\\n\\t\\ta = int(a)\\n\\t\\tprint(a)\\nmain()\\n\",\n \"a = [int(n) for n in input().split()]\\nprint(a[0] * a[1] // 2)\\n\",\n \"(x, y) = [int(m) for m in input().split()]\\narea = x * y\\nprint(int(area / 2))\\n\",\n \"dimensions = input('')\\ndimensions = [int(i) for i in dimensions.split(' ')]\\narea = 1\\nfor i in dimensions:\\n\\tarea *= i\\nprint(area // 2)\\n\",\n \"siz_arr = list(map(int, input().rstrip().split()))\\nm = siz_arr[0]\\nn = siz_arr[1]\\nroww = max(m, n)\\ncoll = m + n - roww\\nif coll % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(roww * int(coll / 2) + int(roww / 2)))\\n\",\n \"from sys import stdin\\n(x, y) = stdin.readline().split(' ')\\nprint(int(x) * int(y) // 2)\\n\",\n \"get = lambda : list(map(int, input().split()))\\n(a, b) = get()\\nprint(a * b // 2)\\n\",\n \"ips = input().split()\\nM = int(ips[0])\\nN = int(ips[1])\\nprint(int(M * N / 2))\\n\",\n \"class domino:\\n\\n\\tdef __init__(self):\\n\\t\\tself.input_l = list(map(int, input().split()))\\n\\t\\tself.solve()\\n\\n\\tdef solve(self):\\n\\t\\tself.m_x = self.input_l[0] * self.input_l[1]\\n\\t\\tresult = self.m_x // 2\\n\\t\\tprint(result)\\nd = domino()\\n\",\n \"(m, n) = map(int, input().split())\\ns = 0\\nt = m * n\\nif t % 2 == 1:\\n\\tt -= 1\\nprint(t // 2)\\n\",\n \"a = input()\\nmass = a.split()\\nd1 = int(mass[0])\\nd2 = int(mass[1])\\nif d1 % 2 != 0 and d2 % 2 != 0:\\n\\tprint(d1 * d2 // 2)\\nelse:\\n\\tprint(d1 * d2 // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nsq = 2\\nvalue = int(m * n / sq)\\nprint(value)\\n\",\n \"(x, y) = input().split()\\nboardsize = int(x) * int(y)\\nnumOfDoms = int(boardsize) // 2\\nprint(numOfDoms)\\n\",\n \"dimensions = input().split(' ')\\nm = int(dimensions[0])\\nn = int(dimensions[1])\\narea = m * n\\nif area % 2 == 0:\\n\\tprint(area // 2)\\nelse:\\n\\tprint((area - 1) // 2)\\n\",\n \"(m, n) = input().split(' ')\\noutput = int(m) * int(n) // 2\\nprint(output)\\n\",\n \"import math\\nrectangleArray = input().split(' ')\\narea = int(rectangleArray[0]) * int(rectangleArray[1])\\nprint(math.floor(area / 2))\\n\",\n \"firstLine = input().split()\\nm = int(firstLine[0])\\nn = int(firstLine[1])\\nanswer = int(m * n / 2)\\nprint(answer)\\n\",\n \"(m, n) = map(int, input().split())\\nif m >= 1 and m <= n and (n <= 16):\\n\\tb = m * n // 2\\nprint(b)\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nsquare = m * n\\nif square % 2 == 0:\\n\\tprint(int(square / 2))\\nelse:\\n\\tprint(square // 2)\\n\",\n \"(n, m) = map(int, input().split())\\ns1 = m // 2 * n + n * (m % 2) // 2\\ns2 = n // 2 * m + m * (n % 2) // 2\\nprint(max(s1, s2))\\n\",\n \"def dominoes(check):\\n\\treturn check // 2\\n(m, n) = map(int, input().strip().split())\\ncheck = m * n\\nprint(dominoes(check))\\n\",\n \"(m, n) = map(int, input().split())\\ntemp1 = m // 2\\nsum = temp1 * n\\ntemp2 = m % 2\\nif temp2 == 1:\\n\\tsum += n // 2\\nprint(sum)\\n\",\n \"def dominoPiling(M, N):\\n\\tif M * N % 2 == 0:\\n\\t\\treturn M * N\\n\\telse:\\n\\t\\treturn M * N - 1\\nMN = input().split()\\nM = int(MN[0])\\nN = int(MN[1])\\nres = dominoPiling(M, N)\\nprint(int(res / 2))\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\nc = math.floor(a * b / 2)\\nprint(c)\\n\",\n \"def main():\\n\\t(s_edge, l_edge) = map(int, input().split())\\n\\tprint(s_edge * l_edge // 2)\\nmain()\\n\",\n \"from math import ceil\\n(m, n) = [int(i) for i in input().split()]\\nx = m * n\\ny = x // 2\\nprint(y)\\n\",\n \"from math import floor\\n(m, n) = map(int, input().split())\\ndomino_size = 2\\nmax_domino = floor(m * n / domino_size)\\nprint(max_domino)\\n\",\n \"a = input()\\nnum = [int(n) for n in a.split()]\\nm = num[0]\\nn = num[1]\\nprint(m * n // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ntotal = m * n\\nif total % 2 == 0:\\n\\tprint(int(total / 2))\\nelse:\\n\\tprint(int((total - 1) / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nspace = m * n\\ncount = space // 2\\nprint(count)\\n\",\n \"(a, b) = map(int, input().split())\\nk = a * b // 2\\nprint(k)\\n\",\n \"import sys\\n(M, N) = map(int, sys.stdin.read().split())\\nprint('%d' % (M * N / 2))\\n\",\n \"from sys import stdin\\ninput = stdin.readline\\n\\ndef main():\\n\\t(m, n) = map(int, input().split())\\n\\tprint(m * n // 2)\\nmain()\\n\",\n \"x = [int(i) for i in input().split()]\\nn = x[0]\\nm = x[1]\\ns = n * m\\ncount = s // 2\\nprint(count)\\n\",\n \"x = input()\\n(aa, bb) = x.split()\\na = int(aa)\\nb = int(bb)\\nm = max(a, b)\\nn = min(a, b)\\nrow = m\\ncol = int(n / 2)\\nres = row * col\\nrow = int(m / 2)\\ncol = n\\nres = max(res, row * col)\\nresidual = a * b - res * 2\\nres = res + int(residual / 2)\\nprint(res)\\n\",\n \"line = input().split()\\nm = int(line[0])\\nn = int(line[1])\\nnumber = 0\\nif n % 2 == 0:\\n\\tnumber = n / 2 * m\\nelse:\\n\\tmar = n // 2\\n\\tcountone = n // 2 * m\\n\\tif m % 2 == 0:\\n\\t\\tmar_1 = m / 2\\n\\t\\tcount = countone + mar_1\\n\\telse:\\n\\t\\tmar_1 = m // 2\\n\\t\\tcount = countone + mar_1\\n\\tnumber = count\\nprint(int(number))\\n\",\n \"import sys\\nnumbers = [int(i) for i in sys.stdin.readline().split()]\\nM = numbers[0]\\nN = numbers[1]\\nif 1 <= M <= N <= 16:\\n\\tif M * N % 3 == 1 or M * N % 3 == 2:\\n\\t\\tb = M * N / 2\\n\\t\\tprint(int(b))\\n\\telse:\\n\\t\\tb = M * N / 2\\n\\t\\tprint(int(b))\\n\",\n \"l = list(input().split())\\nm = int(l[0])\\nn = int(l[1])\\nif m % 2 == 0:\\n\\tprint(m // 2 * n)\\nelif n % 2 == 0:\\n\\tprint(n // 2 * m)\\nelse:\\n\\tprint(m // 2 * n + n // 2)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\ntotal_sq = M * N\\ndomino_ar = 2 * 1\\nprint(math.floor(total_sq / domino_ar))\\n\",\n \"(n, k) = input().split()\\nn = int(n)\\nk = int(k)\\nif n * k % 2 == 0:\\n\\tprint(round(n * k / 2))\\nelif n * k % 2 == 1:\\n\\tprint(round(n * k / 2 - 0.5))\\n\",\n \"(m, n) = map(int, input().split())\\npovrsina = m * n\\ndomino = 2\\nprint(povrsina // domino)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nans = max(m, n) * min(m, n) / 2\\nprint(int(ans))\\n\",\n \"t = list(map(int, input().split()))\\n(m, n) = (t[0], t[1])\\nk = m * n // 2\\nprint(k)\\n\",\n \"(x, y) = input().split()\\n(q, w) = (int(x), int(y))\\nit = q * w // 2\\nprint(it)\\n\",\n \"masukan = input()\\nmasukan2 = []\\nfor i in masukan.split(' '):\\n\\tmasukan2 = masukan2 + [i]\\nm = int(masukan2[0])\\nn = int(masukan2[1])\\nkeluaran = int(m * n / 2)\\nprint(keluaran)\\n\",\n \"a = input().split()\\nfor i in range(len(a)):\\n\\ta[i] = int(a[i])\\nb = a[0] * a[1]\\nc = b // 2\\nprint(c)\\n\",\n \"n = input()\\nn = n.split()\\ntry:\\n\\tif 3 > len(n) > 1:\\n\\t\\tm = int(n[0])\\n\\t\\tn = int(n[1])\\n\\t\\tprint(m * n // 2)\\n\\telse:\\n\\t\\tprint('INVALID INPUTS')\\nexcept:\\n\\tprint('INVALID INPUTS')\\n\",\n \"(m, n) = input('').split(' ')\\na = int(m)\\nb = int(n)\\np = a * b\\nprint(p // 2)\\n\",\n \"dim = input().split()\\nspace = int(dim[0]) * int(dim[1])\\npieces = int(space / 2)\\nprint(pieces)\\n\",\n \"m_n = input()\\ncont1 = ''\\nfor i in m_n:\\n\\tif i.isdigit():\\n\\t\\tcont1 += i\\nif 1010 <= int(cont1) <= 1616:\\n\\tcont1new = cont1\\n\\tcont1 = cont1[:2]\\n\\tcont2 = cont1new[2:]\\n\\tresult = int(cont1) * int(cont2)\\n\\tmax_result = int(result) // 2\\n\\tprint(max_result)\\nelif int(cont1) < 1010:\\n\\tcont1n = cont1\\n\\tcont3 = cont1[0]\\n\\tcont4 = cont1n[1:]\\n\\tresult = int(cont3) * int(cont4)\\n\\tmax_result = result // 2\\n\\tprint(max_result)\\n\",\n \"c = input()\\nx = c.split(' ')\\nv = []\\nfor i in x:\\n\\tv.append(int(i))\\nprint(v[0] * v[1] // 2)\\n\",\n \"(m, n) = input().split()\\n(m, n) = (int(m), int(n))\\ncounter = 0\\nif m % 2 == 0:\\n\\tcounter += m / 2 * n\\nelif n % 2 == 0:\\n\\tcounter += n / 2 * m\\nelif n == 1:\\n\\tpass\\nelif m > 1:\\n\\tcounter += (m - 1) / 2 * n\\n\\tcounter += (n - 1) / 2\\nelse:\\n\\tcounter += (n - 1) / 2\\nprint(int(counter))\\n\",\n \"lst = list(map(lambda x: int(x), input().split()))\\nprint(lst[0] * lst[1] // 2)\\n\",\n \"k = list(map(int, input().split()))\\nif k[0] * k[1] % 2 == 1:\\n\\tprint(int((k[0] * k[1] - 1) / 2))\\nelse:\\n\\tprint(int(k[0] * k[1] / 2))\\n\",\n \"import math\\nmn = list(map(int, input().split()))\\nk = math.floor(mn[0] * mn[1] / 2)\\nprint(k)\\n\",\n \"(l, w) = list(map(int, input().split(' ')))\\narea = l * w\\ndomino_area = 2 * 1\\nprint(area // domino_area)\\n\",\n \"(f, y) = input().split()\\nf = int(f)\\ny = int(y)\\na = int(f * y / 2)\\nprint(a)\\n\",\n \"(x, y) = [int(x) for x in input('').split()]\\nar = x * y\\nprint(int(x * y / 2))\\n\",\n \"import math\\nst = ''\\n\\ndef func(a, b):\\n\\treturn a * b // 2\\nfor _ in range(1):\\n\\t(a, b) = map(int, input().split())\\n\\tst += str(func(a, b)) + '\\\\n'\\nprint(st)\\n\",\n \"(m, n) = [int(s) for s in input().split()]\\nkol = 0\\nif m % 2 == 0 or n % 2 == 0:\\n\\tif m % 2 == 0:\\n\\t\\tkol += m // 2\\n\\t\\tkol *= n\\n\\telse:\\n\\t\\tkol += n // 2\\n\\t\\tkol *= m\\nif m % 2 == 1 and n % 2 == 1:\\n\\tif m > n:\\n\\t\\tkol += m // 2\\n\\t\\tkol *= n\\n\\t\\tkol += n // 2\\n\\telse:\\n\\t\\tkol += n // 2\\n\\t\\tkol *= m\\n\\t\\tkol += m // 2\\nprint(kol)\\n\",\n \"g = str(input()).split()\\nm = int(g[0])\\nn = int(g[1])\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"b = input()\\nlist1 = b.split(' ')\\nM = int(list1[0])\\nN = int(list1[1])\\noutput = M * N // 2\\nprint(output)\\n\",\n \"def max_dominoes():\\n\\t(m, n) = input().split()\\n\\t(m, n) = (int(m), int(n))\\n\\tif 1 <= m <= n <= 16:\\n\\t\\tresult = m * n\\n\\t\\treturn result // 2\\nprint(max_dominoes())\\n\",\n \"entrada = input().split(' ')\\nentrada = int(entrada[0]) * int(entrada[1])\\nprint(entrada // 2)\\n\",\n \"from sys import stdin, stdout\\nfrom math import floor\\n(m, n) = list(map(int, stdin.readline().rstrip().split()))\\nstdout.write(str(int(floor(m * n / 2))))\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\nif n % 2 == 0:\\n\\tf = n // 2 * m\\nelif m % 2 == 0:\\n\\tf = n * (m // 2)\\nelse:\\n\\tf = m * (n // 2) + m // 2\\nprint(f)\\n\",\n \"rc = input().split()\\nm = int(rc[0])\\nn = int(rc[1])\\nprint(int(m * n / 2))\\n\",\n \"entrada = input().split(' ')\\nM = int(entrada[0])\\nN = int(entrada[1])\\nprint(int(M * N / 2))\\n\",\n \"from sys import stdin, stdout\\ninp = stdin.readline\\nout = stdout.write\\n(M, N) = map(int, inp().strip().split())\\nout(str(M * N // 2))\\n\",\n \"(R, C) = map(int, input().split())\\nr = R * C\\nif r % 2 == 0:\\n\\tprint(int(r / 2))\\nelse:\\n\\tprint(int((r - 1) / 2))\\n\",\n \"import math\\nx = list(map(int, input().split(' ')))\\na = x[0]\\nb = x[1]\\nc = a * b\\nif c / 2 == 0:\\n\\tprint(c / 2)\\nelse:\\n\\tprint(math.floor(c / 2))\\n\",\n \"a = [int(i) for i in input().split()]\\n(m, n) = (a[0], a[1])\\nres = m * n\\nif res % 2 == 0:\\n\\tprint(int(res / 2))\\nelse:\\n\\tprint(int(res / 2))\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\nc = 0\\nif n % 2 == 0 or m % 2 == 0:\\n\\tif n % 2 == 0:\\n\\t\\tc = n // 2\\n\\t\\tc = c * m\\n\\telse:\\n\\t\\tc = m // 2\\n\\t\\tc = c * n\\nelse:\\n\\tn -= 1\\n\\tc = n // 2\\n\\tc = c * m\\n\\tc += (m - 1) // 2\\nprint(c)\\n\",\n \"ii = input().split()\\nprint(int(ii[0]) * int(ii[1]) // 2)\\n\",\n \"line = input()\\nfirstNum = ''\\nsecondNum = ''\\nplaceholder = 0\\nwhile line[placeholder] != ' ':\\n\\tfirstNum = firstNum + str(line[placeholder])\\n\\tplaceholder = placeholder + 1\\nplaceholder = placeholder + 1\\nwhile placeholder < len(line):\\n\\tsecondNum = secondNum + str(line[placeholder])\\n\\tplaceholder = placeholder + 1\\ntotal = int(firstNum) * int(secondNum) / 2\\nprint(int(total))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif 1 <= m <= n <= 16:\\n\\tarea = int(m) * int(n)\\n\\tsq = int(area / 2)\\n\\tprint(sq)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif not m % 2:\\n\\tprint(int(m // 2 * n))\\nelif not n % 2:\\n\\tprint(int(n // 2 * m))\\nelse:\\n\\tprint(int((m - 1) // 2 * n + (n - 1) // 2))\\n\",\n \"(m, n) = list(map(int, input().split()))\\nvisited = [[0 for j in range(n)] for i in range(m)]\\ncount = 0\\nfor i in range(m):\\n\\tfor j in range(n):\\n\\t\\tif i >= 0 and i < m and (i + 1 >= 0) and (j >= 0) and (j < n) and (i + 1 < m) and (visited[i][j] == 0) and (visited[i + 1][j] == 0):\\n\\t\\t\\tvisited[i][j] = 1\\n\\t\\t\\tvisited[i + 1][j] = 1\\n\\t\\t\\tcount += 1\\n\\t\\telif i >= 0 and i < m and (j >= 0) and (j + 1 < n) and (visited[i][j] == 0) and (visited[i][j + 1] == 0):\\n\\t\\t\\tvisited[i][j] = 1\\n\\t\\t\\tvisited[i][j + 1] = 1\\n\\t\\t\\tcount += 1\\nprint(count)\\n\",\n \"a = list(map(int, input().split()))\\nx = a[0] * a[1]\\ny = 0\\ni = 0\\nj = 1\\nwhile y < x - x % 2:\\n\\ty = y + 2\\n\\ti = i + 1\\nprint(i)\\n\",\n \"import math\\n\\ndef main():\\n\\ti = input().split()\\n\\tm = int(i[0])\\n\\tn = int(i[1])\\n\\tif m == 1 and n == 1:\\n\\t\\tprint(0)\\n\\telif m == 1:\\n\\t\\tprint(math.floor(n / 2))\\n\\telif n == 1:\\n\\t\\tprint(math.floor(m / 2))\\n\\telse:\\n\\t\\tx = math.floor(n / 2)\\n\\t\\ty = 0\\n\\t\\tif x != n / 2:\\n\\t\\t\\ty = math.floor(m / 2)\\n\\t\\tout = m * x + y\\n\\t\\tprint(out)\\nmain()\\n\",\n \"in_str = input().split(' ')\\nM = int(in_str[0])\\nN = int(in_str[1])\\nif M % 2 == 0:\\n\\tprint(N * int(M / 2))\\nelif N % 2 == 0:\\n\\tprint(M * int(N / 2))\\nelse:\\n\\tprint(N * int((M - 1) / 2) + int(N / 2))\\n\",\n \"(m, n) = input().split()\\nsquare = int(m) * int(n)\\nprint(square // 2)\\n\",\n \"from sys import stdin\\nargs = stdin.readline().split(' ')\\nm = int(args[0])\\nn = int(args[1])\\nprint(int(m * n / 2))\\n\",\n \"firstLine = [int(x) for x in input().split()]\\nif firstLine[0] * firstLine[1] % 2 == 0:\\n\\tprint(int(firstLine[0] * firstLine[1] / 2))\\nelse:\\n\\tprint(int((firstLine[0] * firstLine[1] - 1) / 2))\\n\",\n \"(m, n) = input().split()\\nS = int(m) * int(n)\\nprint(int(S / 2))\\n\",\n \"line = input()\\n(m, n) = [int(i) for i in line.split()]\\ncalc = m * n\\nif calc & 1:\\n\\tcalc -= 1\\nprint(calc // 2)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nz = a * b\\nif z % 2 == 0:\\n\\tprint(int(z / 2))\\nelse:\\n\\tprint(int(z / 2))\\n\",\n \"n = list(map(int, input().split()))\\n\\ndef jabong(m, n):\\n\\tif m % 2 == 0:\\n\\t\\treturn m * n // 2\\n\\telif n % 2 == 0:\\n\\t\\treturn m * n // 2\\n\\telse:\\n\\t\\treturn (m - 1) // 2 + m * (n - 1) // 2\\nprint(jabong(n[0], n[1]))\\n\",\n \"o = input().split()\\nm = int(o[0])\\nn = int(o[1])\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nk2 = 0\\nk1 = m // 2\\nz = k1 * n\\nif m % 2 != 0:\\n\\tk2 = n // 2\\nprint(z + k2)\\n\",\n \"def solve(m, n):\\n\\ttileArea = 2 * 1\\n\\tboardArea = m * n\\n\\treturn boardArea / tileArea\\n(m, n) = [int(y) for y in input().split()]\\nans = solve(m, n)\\nprint(int(ans))\\n\",\n \"M = str(input())\\nx = M.split(' ')\\nprint(int(x[0]) * int(x[1]) // 2)\\n\",\n \"number = str(input())\\nm = int(number.split(' ')[0])\\nn = int(number.split(' ')[1])\\ndomino_tiles = m * n // 2\\nprint(domino_tiles)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0 and n % 2 == 0:\\n\\tnum = m * n / 2\\nelif m % 2 == 0 and n % 2 != 0:\\n\\tnum = 0.5 * m * n\\nelif m % 2 != 0 and n % 2 == 0:\\n\\tnum = 0.5 * m * n\\nelse:\\n\\tnum = 0.5 * (m * n - 1)\\nnum = int(num)\\nprint(num)\\n\",\n \"s = input().split()\\nn = int(s[0])\\nk = int(s[-1])\\nprint(n * k // 2)\\n\",\n \"i = input()\\nl = i.split(' ')\\nf = []\\nfor i in l:\\n\\tf.append(int(i))\\nh = f[0] * f[1] / 2\\nprint(int(h))\\n\",\n \"(x, y) = map(int, input().split())\\n(q, r) = divmod(x, 2)\\nprint(y * q + r * (y // 2))\\n\",\n \"inp = [int(x) for x in input().split(' ')]\\np = inp[0] * inp[1]\\nprint(p // 2)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nc = int(M * N / 2)\\nprint(c)\\n\",\n \"(m, n) = sorted(map(int, input().split()), reverse=True)\\nprint(m // 2 * n + m % 2 * n // 2)\\n\",\n \"from math import *\\n(m, n) = input().split()\\nM = int(m)\\nN = int(n)\\ncount = 0\\nd1 = N * floor(M / 2)\\ncount += d1\\nif M % 2 != 0:\\n\\tcount += floor(N / 2)\\nprint(count)\\n\",\n \"from math import ceil\\nfrom math import floor\\n\\ndef foo(M, N):\\n\\treturn floor(M * N * 0.5)\\n(a, b) = [int(x) for x in input().split()]\\nprint(foo(a, b))\\n\",\n \"inputt = input()\\n(n, m) = inputt.split(' ')\\nprint(int(int(n) * int(m) / 2))\\n\",\n \"def solve(n, m):\\n\\tif n % 2 == 0 or m % 2 == 0:\\n\\t\\treturn m * n // 2\\n\\telse:\\n\\t\\treturn (m * n - 1) // 2\\nt = 1\\nwhile t > 0:\\n\\t(n, m) = [int(x) for x in input().split()]\\n\\tprint(solve(n, m))\\n\\tt -= 1\\n\",\n \"(m, n) = list(map(int, input().split()))\\nj = m * n\\nif j % 2 == 0:\\n\\tr = j // 2\\n\\tprint(r)\\nelse:\\n\\ts = (j - 1) // 2\\n\\tprint(s)\\n\",\n \"(M, N) = map(int, input().split())\\nS = M * N\\nprint(S // 2)\\n\",\n \"import sys\\nlines = sys.stdin.readlines()\\ndata = lines[0].split(' ')\\narea = int(data[0]) * int(data[1])\\nanswer = area // 2\\nprint(answer)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif M * N % 2 == 0 and M + N >= 2:\\n\\tres = M * N / 2\\nelif M * N % 2 != 0 and M + N >= 2:\\n\\tres = (M * N - 1) / 2\\nelse:\\n\\tres = 0\\nprint(int(res))\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nprint(int(M * N * 0.5))\\n\",\n \"import math\\n\\ndef domino_piling(m, n):\\n\\treturn math.floor(m * n / 2)\\nip = input().split(' ')\\nm = int(ip[0])\\nn = int(ip[1])\\nprint(domino_piling(m, n))\\n\",\n \"import math\\nl = input().split(' ')\\nm = int(l[0])\\nn = int(l[1])\\nprint(math.floor(m * n * 0.5))\\n\",\n \"import re\\ndate = input()\\nandron = re.findall('[0-9]+', date)\\nlength = int(andron[0])\\nwidth = int(andron[1])\\nprint(length * width // 2)\\n\",\n \"import math\\n(x, y) = input('').split()\\nprint(math.trunc(int(x) * int(y) / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nsquares = m * n\\ndomSize = 2\\nans = 0\\nmo = squares % domSize\\nif mo != 0:\\n\\tans = int((squares - 1) / 2)\\nelse:\\n\\tans = int(squares / 2)\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nnum = m * n\\nif num % 2 == 0:\\n\\tprint(num // 2)\\nelse:\\n\\tout = (num - 1) // 2\\n\\tprint(out)\\n\",\n \"m = input()\\na = m.split()\\nb = []\\nfor i in a:\\n\\tb.append(int(i))\\narea = b[0] * b[1]\\nprint(int(area / 2))\\n\",\n \"(n, m) = map(int, input().split())\\ns = n * m\\nif s % 2 == 0:\\n\\ts1 = s // 2\\n\\tprint(s1)\\nelse:\\n\\ts1 = s // 2\\n\\tprint(s1)\\n\",\n \"(n, m) = map(int, input().split())\\narea = n * m\\ncount = 0\\nfor i in range(area):\\n\\tif area <= 2 * i:\\n\\t\\tcount = count + 1\\nprint(count)\\n\",\n \"string = input().split()\\nM = int(string[0])\\nN = int(string[1])\\nif M % 2 == 0 or N % 2 == 0:\\n\\tc = M * N / 2\\nelse:\\n\\tc = M * N // 2\\nprint(int(c))\\n\",\n \"s = input().split()\\na = int(s[0])\\nb = int(s[1])\\nres = 0\\nif a > 1 or b > 1:\\n\\tpoa = a / 2\\n\\tres += int(poa) * b\\n\\tif poa != int(poa):\\n\\t\\tpob = b // 2\\n\\t\\tres += pob\\n\\tprint(res)\\nelse:\\n\\tprint(0)\\n\",\n \"tDim = input()\\n(coloane, linii) = tDim.split(' ')\\ncoloane_int = int(coloane)\\nlinii_int = int(linii)\\nif coloane_int % 2 == 0:\\n\\trezpartial = coloane_int * (linii_int / 2)\\nelse:\\n\\trezpartial = (coloane_int - 1) * (linii_int / 2)\\n\\trezpartial = rezpartial + linii_int / 2\\nrezpartial_int = int(rezpartial)\\nprint(rezpartial_int)\\n\",\n \"(a, b) = input().split()\\nm = int(a)\\nn = int(b)\\nif m % 2 == 0:\\n\\tdomino = m // 2 * n\\n\\tprint(domino)\\nelif n % 2 == 0:\\n\\tdomino = n // 2 * m\\n\\tprint(domino)\\nelse:\\n\\tdomino = m // 2 * n + n // 2\\n\\tprint(domino)\\n\",\n \"s = [int(x) for x in input().split()]\\nprint(int(s[0] * s[1] / 2))\\n\",\n \"cad = input().split(' ')\\nn1 = int(cad[0])\\nn2 = int(cad[1])\\nres = n1 * n2\\nprint(res // 2)\\n\",\n \"def int_input_spliter_and_reciever():\\n\\tliste = []\\n\\tfor i in input().strip().split():\\n\\t\\tliste.append(int(i))\\n\\treturn liste\\n(n, m) = int_input_spliter_and_reciever()\\nboard = n * m\\nif board % 2:\\n\\tprint((board - 1) // 2)\\nelse:\\n\\tprint(board // 2)\\n\",\n \"n = input()\\nn = n.split(' ')\\nk = int(n[0]) * int(n[1])\\nprint(str(k // 2))\\n\",\n \"args = input().split(' ')\\nm = int(args[0])\\nn = int(args[1])\\nprint(n * m // 2)\\n\",\n \"(x, y) = list(map(int, input().split()))\\nif x % 2 == 0:\\n\\tprint(int(x / 2 * y))\\nelif y % 2 == 0:\\n\\tprint(int(y / 2 * x))\\nelse:\\n\\tprint(int(x // 2 * y + y // 2))\\n\",\n \"(m, n) = map(int, input().split())\\nif 1 <= m <= n <= 16:\\n\\tans = m * n // 2\\nprint(ans)\\n\",\n \"(a, b) = [int(i) for i in input().split()]\\nimport math\\nr = math.floor(a * b / 2)\\nprint(r)\\n\",\n \"import math\\nscanner = lambda : map(int, input().split())\\n(m, n) = scanner()\\nprint(math.floor(m * n / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nans = m // 2 * n\\nif m % 2 == 0:\\n\\tpass\\nelif n % 2 == 0:\\n\\tans += n // 2\\nelse:\\n\\tans += (n - 1) // 2\\nprint(ans)\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\nx = []\\nfor i in list_we_use:\\n\\tx.append(int(i))\\ny = x[0] * x[1] / 2\\nprint(int(y))\\n\",\n \"(b, l) = [int(i) for i in input().split()]\\nn = b * l // 2\\nprint(n)\\n\",\n \"__author__ = 'skinman95'\\nfrom sys import stdin\\n\\ndef main():\\n\\tline = stdin.readline().strip()\\n\\twhile len(line) != 0:\\n\\t\\t(m, n) = [int(c) for c in line.split()]\\n\\t\\tprint(m * n // 2)\\n\\t\\tline = stdin.readline().strip()\\nmain()\\n\",\n \"import math\\n(m, n) = input().split()\\narea = int(m) * int(n)\\nres = math.floor(area / 2)\\nprint(res)\\n\",\n \"(m, n) = map(int, input().split())\\nans = m // 2 * n\\nr = m % 2\\nif r:\\n\\tans += n // 2\\nprint(ans)\\n\",\n \"strochka = input()\\nstrochkanew = strochka.split()\\nn1 = int(strochkanew[0])\\nn2 = int(strochkanew[1])\\ns = n1 * n2\\nl = s // 2\\nprint(l)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nluas = m * n\\ndomino = luas // 2\\nprint(domino)\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\no = []\\nfor i in list_we_use:\\n\\to.append(int(i))\\na = o[0] * o[1]\\nprint(a // 2)\\n\",\n \"d = str(input())\\ns = d.split()\\nm = int(s[0])\\nn = int(s[1])\\npa = m * n\\nans = 0\\nif pa % 2 == 1:\\n\\tpa -= 1\\n\\tans = int(pa / 2)\\nelse:\\n\\tans = int(pa / 2)\\nprint(ans)\\n\",\n \"D = input('')\\nD = D.split()\\nM = int(D[0])\\nN = int(D[1])\\nif M % 2 == 0:\\n\\tX = M // 2\\n\\tRes = X * N\\nelse:\\n\\tXP = M // 2\\n\\tY = N\\n\\tX = N // 2\\n\\tRes = XP * Y + X\\nprint(Res)\\n\",\n \"from math import *\\nfrom collections import deque\\nfrom copy import deepcopy\\nimport sys\\n\\ndef inp():\\n\\treturn sys.stdin.readline().rstrip('\\\\r\\\\n')\\n\\ndef multi():\\n\\treturn map(int, input().split())\\n\\ndef lis():\\n\\treturn list(map(int, inp().split()))\\n\\ndef out(var):\\n\\tsys.stdout.write(str(var))\\n\\ndef printlist(a):\\n\\tfor p in range(0, len(a)):\\n\\t\\tout(str(a[p]) + ' ')\\n\\ndef isPrime(n):\\n\\tif n <= 1:\\n\\t\\treturn False\\n\\tif n <= 3:\\n\\t\\treturn True\\n\\tif n % 2 == 0 or n % 3 == 0:\\n\\t\\treturn False\\n\\ti = 5\\n\\twhile i * i <= n:\\n\\t\\tif n % i == 0 or n % (i + 2) == 0:\\n\\t\\t\\treturn False\\n\\t\\ti = i + 6\\n\\treturn True\\n(n, m) = multi()\\nout(n * m // 2)\\n\",\n \"m = input()\\nfor i in range(len(m)):\\n\\tif m[i] == ' ':\\n\\t\\ta = i\\n\\t\\tbreak\\nprint(int(m[:a]) * int(m[a + 1:]) // 2)\\n\",\n \"(n, k) = input().split()\\nn = int(n)\\nk = int(k)\\nsquares = n * k\\nif squares % 2 == 0:\\n\\tno = squares / 2\\nelse:\\n\\tno = (squares - 1) / 2\\nprint(int(no))\\n\",\n \"(m, n) = map(int, input().split())\\narr = [[0 for j in range(n)] for i in range(m)]\\ncount = 0\\nfor i in range(m):\\n\\tfor j in range(n - 1):\\n\\t\\tif not arr[i][j] and (not arr[i][j + 1]):\\n\\t\\t\\tarr[i][j] = arr[i][j + 1] = 1\\n\\t\\t\\tcount += 1\\nfor j in range(n):\\n\\tfor i in range(m - 1):\\n\\t\\tif not arr[i][j] and (not arr[i + 1][j]):\\n\\t\\t\\tarr[i][j] = arr[i + 1][j] = 1\\n\\t\\t\\tcount += 1\\nprint(count)\\n\",\n \"numbers = str(input())\\nlistt = numbers.split()\\nm = listt[0]\\nn = listt[1]\\nboard = int(m) * int(n)\\noutput = board // 2\\nprint(output)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\ndsquares = 2 * 1\\nprint(a // dsquares)\\n\",\n \"(M, N) = map(int, input().split())\\ns = M * N\\ndom = 0\\nif s % 2 == 0:\\n\\tdom = s / 2\\nelse:\\n\\tdom = (s - 1) / 2\\nprint(int(dom))\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\ntotal = M // 2 * N + M % 2 * (N // 2)\\nprint(total)\\n\",\n \"(l, b) = input().split(' ')\\nif int(l) % 2 == 0:\\n\\tprint(int(int(b) * (int(l) / 2)))\\nelif int(l) % 2 != 0 and int(b) % 2 == 0:\\n\\tprint(int((int(l) - 1) / 2 * int(b) + int(b) / 2))\\nelif int(l) % 2 != 0 and int(b) % 2 != 0:\\n\\tprint(int((int(l) - 1) / 2 * int(b) + (int(b) - 1) / 2))\\n\",\n \"import math\\nx = input()\\ny = math.floor(int(x.split()[0]) * int(x.split()[1]) / 2)\\nprint(str(y))\\n\",\n \"(n, m) = map(int, input().split(' '))\\n\\ndef solve(n, m):\\n\\tif n * m % 2 == 0:\\n\\t\\tprint(m * n // 2)\\n\\telse:\\n\\t\\tprint((m * n - 1) // 2)\\nsolve(n, m)\\n\",\n \"nu = input().split()\\nprint(int(nu[0]) * int(nu[1]) // 2)\\n\",\n \"(n, p) = map(int, input().split())\\nprint(n * p // 2)\\n\",\n \"from math import *\\n(m, n) = list(map(int, input().split()))\\narea = 2\\ncount = ceil(int(m * n / area))\\nprint(count)\\n\",\n \"(x, y) = map(int, input().split())\\nxy = x * y\\nprint((xy - xy % 2) // 2)\\n\",\n \"a = input()\\nnums = a.split()\\nm = int(nums[0])\\nn = int(nums[1])\\nif m % 2 == 0 or n % 2 == 0:\\n\\tout = m * n / 2\\nelse:\\n\\tout = (m * n - 1) / 2\\nprint(int(out))\\n\",\n \"a = input()\\na = list(map(int, a.split()))\\nm = a[0]\\nn = a[1]\\nhc = int(m / 2)\\nvc = n\\ntc = hc * vc\\nif m % 2 != 0:\\n\\tec = int(n / 2)\\n\\ttc = tc + ec\\nprint(tc)\\n\",\n \"import math\\na = list(map(int, input().split()))\\nprint(int(a[0] * a[1] / 2))\\n\",\n \"def func(x):\\n\\treturn x // 2\\n(m, n) = map(int, input().split())\\nprint(func(m * n))\\n\",\n \"def main():\\n\\tdimensions = list(map(int, input().split()))\\n\\tproduct = dimensions[0] * dimensions[1]\\n\\treturn product // 2\\nprint(main())\\n\",\n \"(n, m) = map(int, input().split())\\nk = 2\\nl = 1\\nj = n * m\\np = j / k\\nprint(int(p))\\n\",\n \"def sol(a, b):\\n\\treturn a * b // 2\\n(a, b) = map(int, input().split(' '))\\nprint(sol(a, b))\\n\",\n \"SQUARES_PARA = input().split(' ')\\nSQUARES_AREA = int(SQUARES_PARA[0]) * int(SQUARES_PARA[1])\\nprint(int(SQUARES_AREA / 2))\\n\",\n \"s1 = input()\\nl1 = list(s1.split(' '))\\nm = int(l1[0])\\nn = int(l1[1])\\na = m * n\\ncount = 0\\nwhile 1:\\n\\tif a == 0 or a == 1:\\n\\t\\tbreak\\n\\ta = a - 2\\n\\tcount = count + 1\\nprint(count)\\n\",\n \"(a, b) = [int(i) for i in input().split()]\\nx = a * b\\nz = x // 2\\nprint(z)\\n\",\n \"(a, b) = map(int, input('').split(' '))\\nbigger = max(int(a / 2) * b, int(b / 2) * a)\\nans = bigger\\nif bigger == int(a / 2) * b:\\n\\tans = ans + a % 2 * int(b / 2)\\nelse:\\n\\tans = ans + b % 2 * int(a / 2)\\nprint(ans)\\n\",\n \"l = list(map(int, input().rstrip().split()))\\nn = l[0]\\nm = l[1]\\nif n == 1 and m == 2 or (n == 2 and m == 1):\\n\\tprint(1)\\n\\texit()\\nx = 0\\ny = 0\\nif n % 2 == 0:\\n\\tx = n // 2\\n\\ty = m\\n\\tprint(x * y)\\n\\texit()\\nelse:\\n\\tx = n // 2\\n\\tif m % 2 == 0:\\n\\t\\ty = m\\n\\t\\tprint(x * y + m // 2)\\n\\t\\texit()\\n\\telse:\\n\\t\\ty = m\\n\\t\\tprint(x * y + m // 2)\\n\",\n \"(a, b) = [int(i) for i in input().split()]\\nreszta = a % 2\\ncale = int(a / 2)\\ncount = 0\\ncount = b * cale + reszta * int(b / 2)\\nprint(count)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nans = m * n\\ngiven = 2\\nprint(int(ans / given))\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nsquares = m // 2 * n\\nif m % 2 == 1:\\n\\tsquares += n // 2\\nprint(squares)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ncount = 0\\nif n % 2 == 0:\\n\\tcount = m * (n // 2)\\nelif n % 2 != 0:\\n\\tcount = round((n - 1) * (m / 2) + m // 2)\\nprint(count)\\n\",\n \"(M, N) = map(int, input().split())\\na = M * N\\nb = a // 2\\nprint(b)\\n\",\n \"ipt = input()\\nipt = ipt.strip().split()\\nm = int(ipt[0])\\nn = int(ipt[1])\\nprint(m * n // 2)\\n\",\n \"(m, n) = input().split()\\nn = int(n)\\nm = int(m)\\nboard_size = m * n\\ncounter = 0\\nfor i in range(board_size):\\n\\tif board_size - 2 > 0:\\n\\t\\tboard_size -= 2\\n\\t\\tcounter += 1\\n\\tif board_size - 2 < 0:\\n\\t\\tprint(counter)\\n\\t\\tbreak\\n\\tif board_size - 2 == 0:\\n\\t\\tcounter += 1\\n\\t\\tprint(counter)\\n\\t\\tbreak\\n\",\n \"(M, N) = map(int, input().split())\\nif N % 2 == 0:\\n\\tresult = N * M / 2\\n\\tprint(int(result))\\nelse:\\n\\tresult = N // 2 * M\\n\\tprint(int(result + M // 2))\\n\",\n \"(n, w) = input().split()\\nprint(int(n) * int(w) // 2)\\n\",\n \"import math\\ns = list(map(int, input().split()))\\nm = s[0]\\nn = s[1]\\nans = math.floor(m * n / 2)\\nprint(int(ans))\\n\",\n \"lst = list(map(int, input().split()))\\nprint(lst[0] * lst[1] // 2)\\n\",\n \"import sys\\ndata = sys.stdin.readlines()[0].split()\\n(n, m) = (int(data[0]), int(data[1]))\\nif n % 2 == 1 and m % 2 == 1:\\n\\tsys.stdout.write(str(int((n * m - 1) / 2)))\\nelse:\\n\\tsys.stdout.write(str(int(n * m / 2)))\\n\",\n \"ls = [int(x) for x in input().split()]\\nprint(ls[0] * ls[1] // 2)\\n\",\n \"(M, N) = list(map(int, input().split()))\\nboard = M * N\\ny = board // 2\\nprint(y)\\n\",\n \"(m, n) = map(int, input().split())\\nsol = -1\\nif m * n % 2:\\n\\tsol = m * (n // 2) + m // 2\\nelif not (m % 2 or n % 2):\\n\\tsol = m // 2 * n\\nelse:\\n\\tif n % 2:\\n\\t\\t(m, n) = (n, m)\\n\\tsol = m * n // 2\\nprint(sol)\\n\",\n \"import math\\nnm = input().split(' ')\\n(n, m) = (int(nm[0]), int(nm[1]))\\nk = math.floor(n * m / 2)\\nprint(k)\\n\",\n \"v = input()\\nsplited = v.split()\\nm = int(splited[0])\\nn = int(splited[1])\\np = 0\\nif m % 2 == 0:\\n\\tp = m / 2 * n\\nelse:\\n\\tp = (m - 1) / 2 * n + int(n / 2)\\nprint(int(p))\\n\",\n \"(m, n) = map(int, input().split())\\ntemp = m * n\\nd = temp // 2\\nprint(d)\\n\",\n \"string = input()\\ns = string.split(' ')\\nn = int(s[0])\\nm = int(s[1])\\ns = m * n\\ncount = s // 2\\nprint(count)\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\nif a % 2 == 0 or b % 2 == 0:\\n\\tprint(int(a * b / 2))\\nelse:\\n\\tx = max((a - 1) * b / 2 + (b - 1) / 2, (b - 1) * a / 2 + (a - 1) / 2)\\n\\tprint(int(x))\\n\",\n \"a = input()\\nlength = a.split()\\nM = int(length[0])\\nN = int(length[1])\\ntotal = 0\\nwhile True:\\n\\tif M > N and N >= 1:\\n\\t\\ttotal += N\\n\\t\\tM = M - 2\\n\\telif M < N and M >= 1:\\n\\t\\ttotal += M\\n\\t\\tN = N - 2\\n\\telif M == N and N > 1:\\n\\t\\ttotal += M\\n\\t\\tN = N - 2\\n\\telse:\\n\\t\\tbreak\\nprint(total)\\n\",\n \"(n, m) = [int(i) for i in input().split()]\\nq = n * m\\nq = q / 2\\nq = int(q)\\nprint(q)\\n\",\n \"(a, b) = map(int, input().split())\\neq = a * b // 2\\nprint(eq)\\n\",\n \"size = list(map(int, input().split()))\\narea = size[0] * size[1]\\ndom = area // 2\\nprint(dom)\\n\",\n \"Str = input()\\nNc = Str.split(' ')\\nN = int(Nc[0])\\nM = int(Nc[1])\\nAns = int(0)\\nAns += int(N / 2) * int(M / 2) * 2\\nExt = N % 2 * (M - 1) + M % 2 * (N - 1) + 1\\nif Ext != 1:\\n\\tAns += int(Ext / 2)\\nprint(int(Ans))\\n\",\n \"x = input()\\nl1 = x.split()\\ny = []\\nl1 = [int(j) for j in l1]\\ny.append(l1)\\nq = y[0][0] * y[0][1]\\nw = q // 2\\nprint(w)\\n\",\n \"st = input().split(' ')\\nM = int(st[0])\\nN = int(st[1])\\nS = M * N\\nprint(S // 2)\\n\",\n \"(m, n) = input().split(' ')\\nkol = int(m) * int(n) // 2\\nprint(kol)\\n\",\n \"(m, n) = map(int, input().split())\\nif m == 1 and n > 1:\\n\\tprint(int(n / 2))\\nelif m > 1 and n == 1:\\n\\tprint(int(m / 2))\\nelse:\\n\\tr = int(m / 2)\\n\\tresult = r * n\\n\\tif m % 2 != 0:\\n\\t\\tresult += int(n / 2)\\n\\tprint(result)\\n\",\n \"(m, n) = map(int, input().split())\\nx = m // 2 * n\\nif m % 2 == 1:\\n\\tx += n // 2\\nprint(x)\\n\",\n \"a = list(map(int, input().split(' ')))\\nfrom math import *\\nno = floor(float(a[0] * a[1] / 2))\\nprint(no)\\n\",\n \"input = list(map(int, input().split()))\\nm = input[0]\\nn = input[1]\\ntotal_dominoes = 0\\nportrait_dominoes = int(n / 2)\\ntotal_dominoes += portrait_dominoes * m\\nvertical_space_left = n - portrait_dominoes * 2\\nif vertical_space_left > 0:\\n\\tlandscape_dominoes = int(m / 2)\\n\\ttotal_dominoes += landscape_dominoes\\nprint(total_dominoes)\\n\",\n \"board = input().split()\\ndominoes = int(board[0]) * int(board[1]) / 2\\nprint(int(dominoes))\\n\",\n \"(M, N) = map(int, input().split())\\nsum = M * N // 2\\nprint(sum)\\n\",\n \"line = input()\\nlist = line.split()\\nn = int(list[0])\\nm = int(list[1])\\na = m * n // 2\\nprint(a)\\n\",\n \"(m, n) = list(map(int, input().strip().split()))\\nz = int((m * n - 1) / 2)\\nw = int(m * n / 2)\\nif m * n % 2 == 0:\\n\\tprint(w)\\nif m * n % 2 != 0:\\n\\tprint(z)\\n\",\n \"def solution():\\n\\t(m, n) = (int(i) for i in input().split())\\n\\tprint(m * n // 2)\\nsolution()\\n\",\n \"s = input('')\\nm = s.split()\\nx = int(m[0])\\ny = int(m[1])\\nif 1 <= x <= y <= 16:\\n\\tprint(int(x * y / 2))\\n\",\n \"(M, N) = map(int, input().split())\\n1 <= M <= N <= 16\\nmax = M * N // 2\\nprint(max)\\n\",\n \"N = [int(x) for x in input().split()]\\nl = N[0] * N[1] / 2\\nprint(int(l))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nans = 0\\nans += m // 2 * n\\nif m & 1:\\n\\tans += n // 2\\nprint(ans)\\n\",\n \"(x, y) = map(int, input().split())\\ncount = 0\\nsum = int(x * y / 2)\\nprint(sum)\\n\",\n \"(m, n) = map(int, input().split())\\nc = m // 2 * n\\nif m % 2 == 1:\\n\\tc += n // 2\\nprint(c)\\n\",\n \"entrada = input()\\nentrada = [int(x) for x in entrada.split()]\\nM = entrada[0]\\nN = entrada[1]\\nprint(int(M * N / 2))\\n\",\n \"(m, n) = map(int, input().split())\\ndomino = 2\\ncount = m * n // domino\\nprint(count)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif M % 2 == 0 or N % 2 == 0:\\n\\tresult = M * N // 2\\nelse:\\n\\tresult = (M * N - 1) // 2\\nprint(result)\\n\",\n \"try:\\n\\t(row, column) = map(int, input().split())\\n\\tif row % 2 == 0 or column % 2 == 0:\\n\\t\\tprint(row * column // 2)\\n\\telse:\\n\\t\\tprint((row - 1) // 2 * column + (column - 1) // 2)\\nexcept EOFError:\\n\\tpass\\n\",\n \"n = list(map(int, input().split(' ')))\\nK = n[0] * n[1]\\nprint(int(K / 2))\\n\",\n \"[M, N] = [int(i) for i in input().split()]\\nif M % 2 == 0 and N % 2 == 0:\\n\\tprint(int(N * M / 2))\\nelif M % 2 == 1 and N % 2 == 0:\\n\\tif M != 1:\\n\\t\\tprint(int(N * M / 2))\\n\\telse:\\n\\t\\tprint(int(N / 2))\\nelif M % 2 == 0 and N % 2 == 1:\\n\\tif N != 1:\\n\\t\\tprint(int(N * M / 2))\\n\\telse:\\n\\t\\tprint(M / 2)\\nelif M % 2 == 1 and N % 2 == 1:\\n\\tprint(int((N - 1) * (M - 1) / 2 + (M - 1) / 2 + (N - 1) / 2))\\n\",\n \"n = input()\\nif n[1] == ' ':\\n\\tprint(int(n[0]) * int(n[2:]) // 2)\\nelse:\\n\\tprint(int(n[0:2]) * int(n[3:]) // 2)\\n\",\n \"import math\\n(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nsq = m * n\\nif sq % 2 == 0:\\n\\tprint(math.trunc(sq / 2))\\nelse:\\n\\tprint(math.trunc((sq - 1) / 2))\\n\",\n \"from sys import stdin\\na = stdin.readline().rstrip().split()\\na = [int(i) for i in a]\\nprint(a[0] * a[1] // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nt = m * n\\nprint(t // 2)\\n\",\n \"(n, k) = map(int, input().split())\\ndomino = n * k // 2\\nprint(domino)\\n\",\n \"import sys\\n\\ndef solve():\\n\\t(m, n) = map(int, input().split())\\n\\tans = m * n // 2\\n\\tprint(ans)\\nsolve()\\n\",\n \"x = input('').split()\\nm = int(x[0])\\nn = int(x[1])\\nnumber = m / 2 * n\\nprint(int(number))\\n\",\n \"input_list = [int(n) for n in input().split()]\\nN = input_list[0]\\nM = input_list[1]\\nprint(int(M * N / 2))\\n\",\n \"n = input().split()\\nM = int(n[0])\\nN = int(n[1])\\na = max(M, N)\\nb = min(M, N)\\nif a % 2 == 0:\\n\\tnum_length = a / 2\\n\\tnum_width = b\\n\\tnum_all = num_length * num_width\\nelse:\\n\\tnum_length = int(a / 2)\\n\\tnum_width = b\\n\\tnum_all = num_length * num_width + int(b / 2)\\nprint(int(num_all))\\n\",\n \"size = [int(n) for n in input().split(' ')]\\nrows = size[0]\\ncols = size[1]\\nif cols % 2 == 0:\\n\\tacross = cols // 2\\n\\tdown = rows\\n\\tprint(across * down)\\nelse:\\n\\tacross = cols // 2\\n\\tdown = rows\\n\\tlast_col = rows // 2\\n\\tprint(across * down + last_col)\\n\",\n \"dims = list(map(int, input().split()))\\nprint(dims[0] * dims[1] // 2)\\n\",\n \"in_string = input()\\nin_string = in_string.split(' ')\\nh = int(in_string[0])\\nv = int(in_string[1])\\nsum = 0\\nif h % 2 == 0:\\n\\tsum = h / 2 * v\\nelif h > 1:\\n\\tsum = (h - 1) / 2 * v\\n\\tif v % 2 == 0:\\n\\t\\tsum = sum + v / 2\\n\\telif v > 1:\\n\\t\\tsum = sum + (v - 1) / 2\\n\\telse:\\n\\t\\tpass\\nelif v > 1:\\n\\tif v % 2 == 0:\\n\\t\\tsum = v / 2\\n\\telse:\\n\\t\\tsum = (v - 1) / 2\\nprint(int(sum))\\n\",\n \"(M, N) = list(map(int, input().strip().split()))\\n\\ndef isEven(num):\\n\\treturn not bool(num % 2)\\nif isEven(M) or isEven(N):\\n\\tprint(int(M * N / 2))\\nelse:\\n\\tprint(int(M * N / 2))\\n\",\n \"def solve(m, n):\\n\\ttileArea = 2 * 1\\n\\tboardArea = m * n\\n\\treturn boardArea / tileArea\\n(m, n) = list(map(int, input().split(' ')))\\nprint(int(solve(m, n)))\\n\",\n \"square = input()\\nsqua = square.split(' ')\\nm = int(squa[0])\\nn = int(squa[1])\\nrs = int(m * n / 2)\\nprint(rs)\\n\",\n \"(m, n) = input().split(' ')\\nif int(m) > 0 and int(n) > 0:\\n\\tprint(int(m) * int(n) // 2)\\n\",\n \"inp = input()\\ninfo = inp.split()\\nresult = int(info[0]) * int(info[1]) / 2\\nprint(int(result))\\n\",\n \"(a, b) = map(int, input().split())\\ny = int(a * b)\\ny = int(y / 2)\\nprint(y)\\n\",\n \"(m, n) = map(int, input().split())\\ncounter_m = int(m / 2)\\nif m % 2 == 0:\\n\\tcounter = counter_m * n\\nelse:\\n\\tcounter = counter_m * n + int(n / 2)\\nprint(counter)\\n\",\n \"import io\\nimport os\\nimport math\\n(m, n) = [int(i) for i in input().split()]\\nprint(math.floor(m * n / 2))\\n\",\n \"t = [int(s) for s in input().split()]\\nprint(t[0] * t[1] // 2)\\n\",\n \"from math import *\\na = input().split()\\nprint(floor(int(a[0]) * int(a[1]) * 0.5))\\n\",\n \"import sys\\n(a, b) = map(int, sys.stdin.readline().split())\\na = a * b\\nm = int((a - a % 2) / 2)\\nprint(m)\\n\",\n \"(m, n) = [int(n) for n in input().split()]\\ncount = m // 2 * n\\nif m % 2 == 1:\\n\\tcount += n // 2\\nprint(count)\\n\",\n \"t = input().split()\\nfor i in range(len(t)):\\n\\tt[i] = int(t[i])\\nm = t[0]\\nn = t[1]\\nif m > n:\\n\\tsmaller = n\\n\\tbig = m\\nelse:\\n\\tsmaller = m\\n\\tbig = n\\nf = smaller // 2\\ng = f * big\\nif smaller % 2 == 1:\\n\\th = big // 2\\n\\tx = g + h\\nelse:\\n\\tx = g\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\ntotsq = m * n\\nres = totsq // 2\\nprint(res)\\n\",\n \"(s, k) = input().split(' ')\\nprint(int(s) * int(k) // 2)\\n\",\n \"parameters = [int(x) for x in input().split()]\\nanswer = int(parameters[0] * parameters[1] / 2)\\nprint(answer)\\n\",\n \"(x, y) = input().split()\\n(x, y) = (int(x), int(y))\\na = int(x // 2 * y)\\nif x % 2 == 1:\\n\\ta += y // 2\\nprint(a)\\n\",\n \"MN = list(map(int, input().split()))\\nM = MN[0]\\nN = MN[1]\\nprint(M * N // 2)\\n\",\n \"(m, n) = [int(x) for x in input().strip().split()]\\ncount = m // 2 * n\\nrem = m % 2 * n\\ncount += rem // 2\\nprint(count)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nsqr = m * n\\nx = int(sqr / 2)\\nprint(x)\\n\",\n \"a = input()\\nb = a.split()\\ns = int(b[0])\\nm = int(b[1])\\nd = s * m // 2\\nprint(d)\\n\",\n \"numbers = input().split()\\nn = int(numbers[0])\\nm = int(numbers[1])\\nres = n * m // 2\\nprint(res)\\n\",\n \"P = input().split(' ')\\nL = [int(x) for x in P]\\ncount = 0\\ntotal = L[0] * L[1]\\nfor x in range(2, total + 1, 2):\\n\\tif x <= total:\\n\\t\\tcount = count + 1\\nprint(count)\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\narea = M * N\\ndominoes = area // 2\\nif 0 < M < 17 and 0 < N < 17:\\n\\tprint(dominoes)\\n\",\n \"(m, n) = [int(x) for x in input('').split()]\\nans = m * n // 2\\nprint(ans)\\n\",\n \"def ii():\\n\\treturn int(input())\\n\\ndef fi():\\n\\treturn float(input())\\n\\ndef si():\\n\\treturn input()\\n\\ndef mi():\\n\\treturn map(int, input().split())\\n\\ndef li():\\n\\treturn list(mi())\\nimport math\\n(n, m) = mi()\\nprint(n * m // 2)\\n\",\n \"def seperateints(x):\\n\\tk = ''\\n\\tl = []\\n\\tfor i in x:\\n\\t\\tif i == ' ':\\n\\t\\t\\tl.append(int(k))\\n\\t\\t\\tk = ''\\n\\t\\t\\tcontinue\\n\\t\\tk = k + i\\n\\tl.append(int(k))\\n\\treturn l\\nx = input()\\nl = seperateints(x)\\nprint(l[0] * l[1] // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nboard_area = m * n\\ndomino_area = 2\\nn_domino = board_area / domino_area\\nprint(int(n_domino))\\n\",\n \"def maxi(m, n):\\n\\treturn m * n // 2\\n(m, n) = map(int, input().split())\\nprint(maxi(m, n))\\n\",\n \"import math\\n[M, N] = [int(i) for i in input().split()]\\na = int(M * N / 2)\\nprint(a)\\n\",\n \"ar = list(map(int, input().rstrip().split()))\\nm = ar[0] * ar[1]\\nprint(int(m / 2))\\n\",\n \"import sys\\nimport math\\n[m, n] = sys.stdin.readline().strip().split(' ')\\nprint(int(math.floor(int(m) * int(n) / 2)))\\n\",\n \"(n, m) = input().split()\\nprint(int(int(n) * int(m) * 0.5))\\n\",\n \"(l, p) = [int(a) for a in input().split(' ')]\\nprint(l * p // 2)\\n\",\n \"inp = input().split()\\n(m, n) = (max(int(inp[0]), int(inp[1])), min(int(inp[0]), int(inp[1])))\\nif m == n:\\n\\tprint(m * n // 2)\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"def create_board(w, h):\\n\\tf = []\\n\\tfor y in range(h):\\n\\t\\tfor x in range(w):\\n\\t\\t\\tf.append([x, y])\\n\\treturn f\\n\\ndef domino_piling(b):\\n\\tfields = b[:]\\n\\ts = 0\\n\\tfor field in fields:\\n\\t\\tif [field[0] + 1, field[1]] in fields:\\n\\t\\t\\ts += 1\\n\\t\\t\\tfields.remove([field[0] + 1, field[1]])\\n\\t\\telif [field[0], field[1] + 1] in fields:\\n\\t\\t\\ts += 1\\n\\t\\t\\tfields.remove([field[0], field[1] + 1])\\n\\treturn s\\nmn = list(map(int, input().split()))\\n(width, height) = (mn[0], mn[1])\\nboard = create_board(width, height)\\nprint(domino_piling(board))\\n\",\n \"def solve(a, b):\\n\\tm = min(a, b)\\n\\tn = max(a, b)\\n\\tres = int(n / 2)\\n\\tres *= m\\n\\tres += int(n % 2 * m / 2)\\n\\treturn res\\n(m, n) = map(int, input().split())\\nprint(solve(m, n))\\n\",\n \"n = input().split()\\nx = int(n[0])\\ny = int(n[1])\\nc = x * y\\nprint(c // 2)\\n\",\n \"(rows, cols) = tuple(map(int, input().split()))\\nif cols % 2 == 0:\\n\\tresult = cols * rows / 2\\nelse:\\n\\tresult = cols // 2 * rows + rows // 2\\nprint(int(result))\\n\",\n \"def cantDominoes(x, y):\\n\\tprint(int(x * y / 2))\\ns = input()\\ns = s.split()\\ncantDominoes(int(s[0]), int(s[1]))\\n\",\n \"x = input()\\n(m, n) = x.split()\\nboard = int(m) * int(n)\\nprint(board // 2)\\n\",\n \"s = input()\\nproduct = 1\\ns = s.split()\\ns = [int(x) for x in s]\\nfor x in s:\\n\\tproduct = product * int(x)\\nr = product // 2\\nprint(r)\\n\",\n \"import sys\\n\\ndef main():\\n\\t(M, N) = [int(x) for x in sys.stdin.readline().strip().split()]\\n\\tprint(M * N // 2)\\nmain()\\n\",\n \"arr = [int(x, 10) for x in input().split()]\\na = arr[0] * arr[1] // 2\\nprint(a)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nz = m * n\\nk = math.floor(z / 2)\\nprint(k)\\n\",\n \"def domino(m, n):\\n\\tif m == 1 and n == 1:\\n\\t\\treturn 0\\n\\telif m == 1:\\n\\t\\treturn n // 2\\n\\telif n == 1:\\n\\t\\treturn m // 2\\n\\telif m % 2 == 0 and n % 2 == 0:\\n\\t\\treturn m * n / 2\\n\\telif m % 2 == 0 and n % 2 == 1:\\n\\t\\treturn domino(m, n - 1) + domino(m, 1)\\n\\telif m % 2 == 1 and n % 2 == 0:\\n\\t\\treturn domino(m - 1, n) + domino(1, n)\\n\\telse:\\n\\t\\treturn domino(m - 1, n - 1) + domino(m, 1) + domino(1, n)\\nargs = input().split()\\nm = int(args[0])\\nn = int(args[1])\\nprint(int(domino(m, n)))\\n\",\n \"import math\\n(m, n) = input().split()\\nans = math.floor(int(m) * int(n) / 2)\\nprint(ans)\\n\",\n \"(z, y) = [int(z) for z in input().split()]\\nif z * y % 2 == 0:\\n\\tprint(int(z * y / 2))\\nelse:\\n\\tprint(z * y // 2)\\n\",\n \"t = input().split(' ')\\nm = int(t[0])\\nn = int(t[1])\\nprint(m * n // 2)\\n\",\n \"from sys import stdin, stdout\\n(n, m) = [int(x) for x in stdin.readline().rstrip().split()]\\nstdout.write(str(n * m // 2))\\n\",\n \"x = input().split(' ')\\nproduct = 1\\nfor i in x:\\n\\tproduct *= int(i)\\nprint(product // 2)\\n\",\n \"a = input().split()\\nlength = int(a[0])\\nwidth = int(a[1])\\nresult = 0\\nif length * width % 2 == 0:\\n\\tresult = int(length * width / 2)\\nelse:\\n\\tresult = int((length * width - 1) / 2)\\nprint(result)\\n\",\n \"s = input().split()\\nx = int(s[0])\\ny = int(s[1])\\nif x % 2 == 1 and y % 2 == 1:\\n\\tprint(int((x * y - 1) / 2))\\nelse:\\n\\tprint(int(x * y / 2))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(m * n / 2 - 0.5))\\n\",\n \"def main():\\n\\tsize = input().split()\\n\\tboard = int(size[0]) * int(size[1])\\n\\tprint(board // 2)\\nmain()\\n\",\n \"(a, b) = map(int, input().split())\\nprint(int(a * b * 0.5))\\n\",\n \"(a, b) = input().split()\\nlength = int(a)\\nwidth = int(b)\\nif length % 2 != 0 and width % 2 != 0:\\n\\tprint(int((length * width - 1) / 2))\\nelse:\\n\\tprint(int(length * width / 2))\\n\",\n \"dominosize = 2 * 1\\ni = input().split()\\nboardsize = int(i[0]) * int(i[1])\\nprint(boardsize // dominosize)\\n\",\n \"import math\\nn = input()\\nline = n.split()\\ns = math.floor(int(line[0]) * int(line[1]) * 0.5)\\nprint(s)\\n\",\n \"def domino_piling():\\n\\t(m, n) = input().split()\\n\\ts = int(m) * int(n)\\n\\td = 2\\n\\tprint(int(s / d))\\ndomino_piling()\\n\",\n \"a = input()\\n(M, N) = [int(i) for i in a.split()]\\nif M % 2 == 0 and N % 2 == 0:\\n\\tnum = int(M * N / 2)\\nif M % 2 != 0 or N % 2 != 0:\\n\\tnum = int(M * N / 2)\\nprint(num)\\n\",\n \"import math\\nimport os\\nimport random\\nimport re\\nimport sys\\nmn = input().rstrip().split()\\nm = int(mn[0])\\nn = int(mn[1])\\nmax = int(m * n / 2)\\nprint(max)\\n\",\n \"(n, m) = [int(i) for i in input().split()]\\nS = n * m\\nprint(S // 2)\\n\",\n \"import math\\n(n, k) = list(map(int, input().split()))\\nprint(math.floor(n * k / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nif m < 2 and n < 2:\\n\\tprint(0)\\nelse:\\n\\tprint(min(n, m) + (max(n, m) - 2) * min(n, m) // 2)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nle = max(M, N)\\npe = min(M, N)\\nif le % 2 == 0:\\n\\tprint(int(le / 2 * pe))\\nelse:\\n\\tprint(int(le // 2 * pe + pe // 2))\\n\",\n \"(hight, wight) = tuple(map(int, input().split()))\\nif hight % 2 == 0:\\n\\tres = hight * wight // 2\\nelif wight % 2 == 0:\\n\\tres = hight * wight // 2\\nelse:\\n\\tres = hight * (wight + 1) // 2 - hight // 2 - 1\\nprint(res)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nabc = int(m * n / 2)\\nprint(abc)\\n\",\n \"bs = [int(i) for i in input().split()]\\nsquares = bs[0] * bs[1]\\nif squares % 2 == 0:\\n\\tprint(int(squares / 2))\\nelse:\\n\\tprint(int((squares - 1) / 2))\\n\",\n \"(m, n) = tuple(map(int, input().split(' ')))\\n\\ndef dominoshki(m, n):\\n\\tmatr = [[0 for j in range(n)] for i in range(m)]\\n\\tfor i in range(1, n + 1):\\n\\t\\tmatr[0][i - 1] = i // 2\\n\\tfor j in range(1, n):\\n\\t\\tif (j + 1) % 2 == 0:\\n\\t\\t\\tfor i in range(1, m):\\n\\t\\t\\t\\tmatr[i][j] = matr[i - 1][j] + (j + 1) / 2\\n\\t\\telse:\\n\\t\\t\\tc = [matr[0][j] + 1, matr[0][j]] * m\\n\\t\\t\\tfor i in range(1, m):\\n\\t\\t\\t\\tmatr[i][j] = matr[i - 1][j] + c[i - 1]\\n\\treturn int(matr[m - 1][n - 1])\\nprint(dominoshki(m, n))\\n\",\n \"print(eval(input().replace(' ', '*')) // 2)\\n\",\n \"(m, n) = list((int(x) for x in input().split()))\\nprint(m * n // 2)\\n\",\n \"a1 = []\\na2 = []\\nb = 0\\nm = 0\\nn = 0\\nd = float(2)\\na1 = input()\\na2 = a1.split()\\nm = float(a2[0])\\nn = float(a2[1])\\nP = m * n\\nif P % d > 0:\\n\\tP = P - 1\\nL = P / d\\nprint(int(L))\\n\",\n \"def get_max_count_dominoes(board_size):\\n\\tsize_dominoe = 2\\n\\tcount_dominoes = board_size // size_dominoe\\n\\treturn count_dominoes\\n(m, n) = map(int, input().split())\\nboard_size = m * n\\nprint(get_max_count_dominoes(board_size))\\n\",\n \"def iip():\\n\\treturn int(input())\\n\\ndef sip():\\n\\treturn input()\\n\\ndef mip():\\n\\treturn map(int, input().split())\\n\\ndef lip():\\n\\treturn list(map(int, input().split()))\\n(m, n) = mip()\\nprint(m * n // 2)\\n\",\n \"(n, k) = map(int, input(' ').split())\\nmax_num = n * k / 2\\nprint(int(max_num))\\n\",\n \"(m, n) = [int(n) for n in input().split()]\\nsize = m * n\\nif 1 <= m <= n <= 16:\\n\\tif size % 2 == 0:\\n\\t\\tprint(int(size / 2))\\n\\telif size % 2 != 0:\\n\\t\\tprint(int((size - 1) / 2))\\n\",\n \"n = list(input().split())\\narea = int(n[0]) * int(n[1])\\nanswer = int(area / 2)\\nprint(answer)\\n\",\n \"import math\\nA = input().split()\\nn = int(A[0])\\nm = int(A[1])\\nans1 = int(0)\\nans2 = int(0)\\nans1 += int(n / 2) * m + n % 2 * m / 2\\nans2 += int(m / 2) * n + m % 2 * n / 2\\nprint(int(max(ans1, ans2)))\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\np = a * b // 2\\nprint(p)\\n\",\n \"(x, y) = [int(i) for i in input().split()]\\nif x % 2 != 0 and y % 2 != 0:\\n\\tprint(x // 2 * y + y // 2)\\nelif x % 2 == 0:\\n\\tprint(x // 2 * y)\\nelse:\\n\\tprint(y // 2 * x)\\n\",\n \"import math\\n(M, N) = input().split()\\nprint(math.floor(int(M) * int(N) / 2))\\n\",\n \"import sys\\nimport math\\n(m, n) = map(int, sys.stdin.readline().split())\\narea = m * n\\nans = math.floor(area / 2)\\nprint(ans)\\n\",\n \"a = map(int, input().split())\\nresult = 1\\nfor x in a:\\n\\tresult *= x\\nprint(int(result / 2))\\n\",\n \"board = str(input())\\nboard_values = board.split(' ')\\nm = int(board_values[0])\\nn = int(board_values[1])\\narea = m * n\\nby_2 = area / 2\\nprint(int(by_2))\\n\",\n \"def how_many(n, m):\\n\\treturn n * m // 2\\n(n, m) = map(int, input().split())\\nprint(how_many(n, m))\\n\",\n \"(x, y) = map(int, input().split())\\ns = 0\\nif y % 2 == 0:\\n\\tb = 0\\n\\ts = y / 2 * x\\nelse:\\n\\tb = 1\\n\\ts = (y - 1) / 2 * x\\nif x % 2 == 0:\\n\\tc = x / 2\\nelse:\\n\\tc = (x - 1) / 2\\ns = s + c * b\\nprint('%d' % s)\\n\",\n \"import sys, math\\ninput = sys.stdin.readline\\n\\ndef getInt():\\n\\treturn int(input())\\n\\ndef getVars():\\n\\treturn map(int, input().split())\\n\\ndef getArr():\\n\\treturn list(map(int, input().split()))\\n\\ndef getStr():\\n\\treturn input().strip()\\n(n, m) = getVars()\\nif m % 2 == 0:\\n\\tm1 = m\\n\\tm2 = n\\nelse:\\n\\tm1 = n\\n\\tm2 = m\\nres = m1 // 2 * m2\\nif m1 % 2 == 1:\\n\\tres += m2 // 2\\nprint(res)\\n\",\n \"N = input()\\nline = N.split()\\nimport math\\nk = math.floor(int(line[0]) * int(line[1]) / 2)\\nprint(k)\\n\",\n \"s = input().split()\\nM = int(s[0])\\nN = int(s[1])\\nk = 0\\nif N > M:\\n\\tk = N // 2\\n\\tL = k * M\\n\\tif M == 2:\\n\\t\\tL = N\\n\\tif M > 2:\\n\\t\\th = N * M\\n\\t\\tL = h // 2\\nelse:\\n\\th = N * M\\n\\tL = h // 2\\nprint(L)\\n\",\n \"import math\\n(m, n) = (int(x) for x in input().split())\\narea = m * n\\ndominoarea = 2\\nx = math.floor(area / 2)\\nprint(x)\\n\",\n \"string = input().split()\\nwidth = int(string[0])\\nheight = int(string[1])\\nif width % 2 == 1 and height % 2 == 1:\\n\\tprint(int((width * height - 1) / 2))\\nelse:\\n\\tprint(int(width * height / 2))\\n\",\n \"desk = input().split()\\na = int(desk[0])\\nb = int(desk[1])\\ns = a * b\\nprint(s // 2)\\n\",\n \"MN = sorted(list(map(lambda x: int(x), input().split(' '))), reverse=True)\\nprint(int(MN[0] * MN[1] * 1 / 2))\\n\",\n \"i = input().split(sep=' ')\\nm = int(i[0])\\nn = int(i[1])\\nres = int(m / 2) * n + m % 2 * int(n / 2)\\nprint(int(res))\\n\",\n \"ipt = input().split()\\n(a, b) = list(map(int, ipt))\\nprint(a * b // 2)\\n\",\n \"(m, n) = list(map(eval, input().split()))\\nprint(m * n // 2)\\n\",\n \"n = list(map(int, input().split()))\\ns = n[0] * n[1]\\nprint(s // 2)\\n\",\n \"ar = input().split()\\nprint(int(int(ar[0]) * int(ar[1]) / 2))\\n\",\n \"(a, b) = map(int, input().split())\\ns = a * b\\np = s // 2\\nprint(p)\\n\",\n \"(m, n) = map(int, input().split())\\nprvi = n // 2 * m\\nprvi += m // 2 * (n - 2 * (n // 2))\\ndrugi = m // 2 * n\\ndrugi += n // 2 * (m - 2 * (m // 2))\\nprint(max(prvi, drugi))\\n\",\n \"w = input()\\nlista = w.split()\\nl1 = int(lista[0])\\nl2 = int(lista[1])\\na = l1 * l2\\nx = a // 2\\nprint(x)\\n\",\n \"def domino_piling():\\n\\t(m, n) = map(int, input().strip().split())\\n\\tif not m or not n:\\n\\t\\treturn 0\\n\\treturn m * n // 2\\nprint(domino_piling())\\n\",\n \"board = str(input())\\nboard_values = board.split(' ')\\nprint(int(int(board_values[0]) * int(board_values[1]) / 2))\\n\",\n \"def Domino(n, m):\\n\\tval = int(n * m / 2)\\n\\treturn val\\n(n, m) = list(map(int, input().split(' ')))\\nprint(Domino(n, m))\\n\",\n \"(M, N) = list(map(int, input().split(' ')))\\nt = M * N\\nans = t // 2\\nprint(ans)\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nboard_size = m * n\\nprint(int(board_size / 2))\\n\",\n \"a = input().split()\\nm = int(a[0])\\nn = int(a[1])\\ns = m * n\\np = s // 2\\nprint(p)\\n\",\n \"(a, b) = map(int, input().split())\\nf = 2\\nprint(a * b // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nA = 2\\nA2 = M * N\\nprint(A2 // A)\\n\",\n \"def dominoPiling():\\n\\t(m, n) = map(int, input().strip().split())\\n\\tif not m or not n:\\n\\t\\treturn 0\\n\\tp = m * n\\n\\tdominos = p // 2\\n\\treturn dominos\\nprint(dominoPiling())\\n\",\n \"inp = input('')\\nx = inp.split(' ')\\nn = int(x[0])\\nm = int(x[1])\\nif m % 2 == 0:\\n\\tt = n\\n\\tn = m\\n\\tm = t\\nif n % 2 == 1:\\n\\tprint(n // 2 * m + m // 2)\\nelse:\\n\\tprint(n // 2 * m)\\n\",\n \"(a, b) = map(int, input().split())\\nif a <= b:\\n\\tsm = a\\n\\tbg = b\\nelse:\\n\\tsm = b\\n\\tbg = a\\nif bg % 2 == 0:\\n\\tans = bg // 2 * sm\\nelse:\\n\\tans = bg // 2 * sm + sm // 2\\nprint(ans)\\n\",\n \"(n, m) = [int(p) for p in input().split()]\\ns = n * m\\nprint(s // 2)\\n\",\n \"s = input().split()\\nm = int(s[0])\\nn = int(s[1])\\nt = m * n\\nx = t / 2\\ny = int(x)\\nprint(y)\\n\",\n \"(length, width) = map(int, input().split())\\narea = length * width\\ndominos = 2\\nprint(int(area / dominos))\\n\",\n \"(k, l) = list(map(int, input().rstrip().split()))\\nprint(k * l // 2)\\n\",\n \"board = input().split()\\nlength_board = int(board[0])\\nbreadth_board = int(board[1])\\narea = length_board * breadth_board\\ndomino_area = 2\\nprint(area // domino_area)\\n\",\n \"import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, copy, functools\\nsys.setrecursionlimit(10 ** 7)\\ninf = 10 ** 20\\neps = 1.0 / 10 ** 10\\nmod = 10 ** 9 + 7\\ndd = [(-1, 0), (0, 1), (1, 0), (0, -1)]\\nddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]\\n\\ndef LI():\\n\\treturn [int(x) for x in sys.stdin.readline().split()]\\n\\ndef LI_():\\n\\treturn [int(x) - 1 for x in sys.stdin.readline().split()]\\n\\ndef LF():\\n\\treturn [float(x) for x in sys.stdin.readline().split()]\\n\\ndef LS():\\n\\treturn sys.stdin.readline().split()\\n\\ndef I():\\n\\treturn int(sys.stdin.readline())\\n\\ndef F():\\n\\treturn float(sys.stdin.readline())\\n\\ndef S():\\n\\treturn input()\\n\\ndef pf(s):\\n\\treturn print(s, flush=True)\\n\\ndef main():\\n\\t(n, m) = LI()\\n\\treturn n * m // 2\\nprint(main())\\n\",\n \"(m, n) = map(int, input().split())\\nc = m * n\\nh = c // 2\\nprint(h)\\n\",\n \"mn = input()\\n(m, n) = mn.split()\\nm = int(m)\\nn = int(n)\\ndominosNumber = int(m * n / 2)\\nprint(dominosNumber)\\n\",\n \"(M, N) = input().split()\\nDs = 2\\nprint(int(M) * int(N) // Ds)\\n\",\n \"import math\\nline = input()\\nnum = line.split()\\na = int(num[0])\\nb = int(num[1])\\nprint(math.floor(a * b / 2))\\n\",\n \"s = input()\\nl = s.split()\\nl[0] = int(l[0])\\nl[1] = int(l[1])\\nprint(int(l[0] * l[1] / 2))\\n\",\n \"m_n = input().split(' ')\\nm = int(m_n[0])\\nn = int(m_n[1])\\nif m % 2 != 0 and n % 2 != 0:\\n\\tsuma_total = m // 2 * n + n // 2\\nelse:\\n\\tsuma_total = m / 2 * n\\nprint(int(suma_total))\\n\",\n \"(n, m) = map(int, input().split())\\nS = n * m\\nprint('{0:.0f}'.format(S // 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nT = 2\\nprint(m * n // T)\\n\",\n \"(n, m) = map(int, input().split())\\nr = n * m\\nk = 2\\nprint(r // 2)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\ns = a * b\\nf = s // 2\\nprint(f)\\n\",\n \"(m, n) = list(map(int, input().rstrip().split()))\\nresult = m * n // 2\\nprint(result)\\n\",\n \"import sys\\nimport math\\n\\ndef main():\\n\\t(M, N) = [int(x) for x in input().split()]\\n\\tprint(math.floor(M * N / 2))\\nmain()\\n\",\n \"from math import floor\\ninput = list(map(int, input().strip().split()))\\narea = input[0] * input[1]\\nprint(floor(area / 2))\\n\",\n \"(m, n) = map(int, input().split(' '))\\npiece = 2 * 1\\narea = m * n\\ndomino = area / piece\\ndomino = int(domino)\\nprint(domino)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nresult = int(area / 2)\\nprint(result)\\n\",\n \"(a, b) = map(int, input().split())\\nboard = a * b\\nresultado = board / 2\\nif board % 2 == 0:\\n\\tprint(int(resultado))\\nif board % 2 == 1:\\n\\tprint(int(resultado - 0.5))\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0 and n % 2 == 0:\\n\\tk = m // 2\\n\\ts = k * n\\n\\tprint(s)\\nelif m == 2:\\n\\tk = m - 1\\n\\ts = k * n\\n\\tprint(s)\\nelif n == 2:\\n\\tk = n - 1\\n\\ts = k * m\\n\\tprint(s)\\nelif m % 2 != 0 and n % 2 == 0:\\n\\tk = (m - 1) // 2\\n\\ts = k * n\\n\\th = n // 2\\n\\tprint(s + h)\\nelif m % 2 == 0 and n % 2 != 0:\\n\\tk = (n - 1) // 2\\n\\ts = k * m\\n\\th = m // 2\\n\\tprint(s + h)\\nelif m % 2 != 0 and n % 2 != 0:\\n\\tk = m - 1\\n\\tj = n - 1\\n\\ts = k * j // 2\\n\\th = n // 2\\n\\ty = m // 2\\n\\tprint(s + h + y)\\n\",\n \"p = input().split()\\nm = int(p[0])\\nn = int(p[1])\\ns = m * n\\nt = int(s / 2)\\nprint(t)\\n\",\n \"from sys import stdin, stdout\\n\\ndef main():\\n\\t(m, n) = map(int, stdin.readline().rstrip().split())\\n\\tdominoNumber = 0\\n\\tif m % 2 == 0 and n % 2 == 0:\\n\\t\\tdominoNumber = int(m * n / 2)\\n\\telif m % 2:\\n\\t\\tdominoNumber = int(m / 2 * n)\\n\\telif n % 2:\\n\\t\\tdominoNumber = int(m * (n / 2))\\n\\telse:\\n\\t\\tdominoNumber = int(m / 2) * n + int(n / 2)\\n\\tstdout.write(str(dominoNumber) + '\\\\n')\\nmain()\\n\",\n \"x = input()\\na = x.split()\\naside = int(a[0])\\nbside = int(a[1])\\nboard = aside * bside\\nprint(board // 2)\\n\",\n \"(l, b) = input().split()\\n(l, b) = (int(l), int(b))\\nprint(l * b // 2)\\n\",\n \"lst = [int(i) for i in input().split()]\\nans = lst[0] * lst[1]\\nans = int(ans / 2)\\nprint(ans)\\n\",\n \"(a, b) = input().split()\\n(a, b) = (int(a), int(b))\\nk = int(0)\\nwhile a != 0 and b != 0 and (a * b > 1):\\n\\tif b > a:\\n\\t\\ta = a + b\\n\\t\\tb = a - b\\n\\t\\ta = a - b\\n\\tk += b\\n\\ta -= 2\\nprint(k)\\n\",\n \"import math\\n\\ndef solve(m, n):\\n\\treturn math.floor(m * n * 0.5)\\n(n, k) = map(int, input().split(' '))\\nc = solve(n, k)\\nprint(c)\\n\",\n \"q = input()\\nlist1 = q.split(' ')\\nf = []\\nfor i in list1:\\n\\tf.append(int(i))\\nt = f[0] * f[1]\\nprint(t // 2)\\n\",\n \"b = list(map(int, input().split()))\\nif b[0] % 2 == 0 or b[1] % 2 == 0:\\n\\tprint(b[0] * b[1] // 2)\\nelif b[0] > 1:\\n\\tprint((b[0] - 1) * b[1] // 2 + b[1] // 2)\\nelif b[1] > 1:\\n\\tprint(b[0] * (b[1] - 1) // 2 + b[0] // 2)\\nelif b[1] == b[0] == 1:\\n\\tprint(0)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nk = m // 2\\nm = m - k * 2\\ncount = n * k\\nif m != 0:\\n\\tcount += n // 2\\nprint(count)\\n\",\n \"sz = input()\\nn = sz.split()\\nsq = int(n[0]) * int(n[1])\\nprint(int(sq / 2))\\n\",\n \"class Solution(object):\\n\\n\\tdef __init__(self):\\n\\t\\t(self.m, self.n) = map(int, input().split())\\n\\t\\trows = cols = 0\\n\\t\\tans = 0\\n\\t\\tif self.m & 1 and self.n & 1:\\n\\t\\t\\trows = self.m\\n\\t\\t\\tcols = self.n - 1\\n\\t\\t\\tans += rows // 2\\n\\t\\telif self.m & 1:\\n\\t\\t\\tcols = self.n\\n\\t\\t\\trows = self.m\\n\\t\\telse:\\n\\t\\t\\tcols = self.m\\n\\t\\t\\trows = self.n\\n\\t\\tans += rows * (cols // 2)\\n\\t\\tprint(ans)\\n\\tpass\\n\\ndef main():\\n\\tSolution()\\n\\tpass\\nmain()\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m * n % 2 == 0:\\n\\tanswer = m * n / 2\\nelse:\\n\\tanswer = int(m * n / 2)\\nprint(int(answer))\\n\",\n \"import math as mt\\n(m, n) = map(int, input().strip().split())\\nres = mt.floor(m / 2 * n)\\nprint(res)\\n\",\n \"rectBoard = input().split()\\nvert = int(rectBoard[0])\\nhoriz = int(rectBoard[1])\\nif horiz * vert % 2 == 0:\\n\\tprint(int(vert * horiz / 2))\\nelse:\\n\\tprint(int((horiz * vert + 1) / 2) - 1)\\n\",\n \"import sys\\nfor (i, line) in enumerate(sys.stdin):\\n\\tif i == 0:\\n\\t\\t(M, N) = (int(line.strip().split(' ')[0]), int(line.strip().split(' ')[1]))\\n\\t\\tprint(M * N // 2)\\n\",\n \"z = input().split(' ')\\nx = int(z[0])\\ny = int(z[1])\\nif x % 2 == 0 and y % 2 == 0 and (x > 1 or y > 1):\\n\\tprint(int(x * y / 2))\\nelif x % 2 != 0 and y % 2 != 0 and (x > 1 or y > 1):\\n\\tprint(int(x * (y - 1) / 2 + (x - 1) / 2))\\nelif x % 2 != 0 and y % 2 == 0 or ((x % 2 == 0 and y % 2 != 0) and (x > 1 or y > 1)):\\n\\tprint(int(x * y / 2))\\nelif x < 2 and y < 2:\\n\\tprint(0)\\n\",\n \"(z, zz) = (input, lambda : list(map(int, z().split())))\\nzzz = lambda : [int(i) for i in stdin.readline().split()]\\n(szz, graph, mod, szzz) = (lambda : sorted(zz()), {}, 10 ** 9 + 7, lambda : sorted(zzz()))\\nfrom string import *\\nfrom re import *\\nfrom collections import *\\nfrom queue import *\\nfrom sys import *\\nfrom collections import *\\nfrom math import *\\nfrom heapq import *\\nfrom itertools import *\\nfrom bisect import *\\nfrom collections import Counter as cc\\nfrom math import factorial as f\\nfrom bisect import bisect as bs\\nfrom bisect import bisect_left as bsl\\nfrom itertools import accumulate as ac\\nfrom itertools import permutations as permu\\n\\ndef lcd(xnum1, xnum2):\\n\\treturn xnum1 * xnum2 // gcd(xnum1, xnum2)\\n\\ndef prime(x):\\n\\tp = ceil(x ** 0.5) + 1\\n\\tfor i in range(2, p):\\n\\t\\tif x % i == 0 and x != 2 or x == 0:\\n\\t\\t\\treturn 0\\n\\treturn 1\\n\\ndef dfs(u, visit, graph):\\n\\tvisit[u] = True\\n\\tfor i in graph[u]:\\n\\t\\tif not visit[i]:\\n\\t\\t\\tdfs(i, visit, graph)\\n(n, m) = zz()\\nt = n * m\\nprint(t // 2)\\n\",\n \"(m1, n1) = input().split()\\nm = int(m1)\\nn = int(n1)\\nprint(int(m * n / 2))\\n\",\n \"s = input()\\ninput_lists = s.split(' ')\\nmatrix = [int(x.strip()) for x in input_lists]\\ndomino = 2\\nmatrix = matrix[0] * matrix[-1]\\nMaximum = matrix / domino\\nprint(int(Maximum))\\n\",\n \"a = [int(i) for i in input().split()]\\nif a[0] % 2 == 0 and a[1] % 2 == 0:\\n\\ts = a[1] * (a[0] // 2)\\nelif a[0] % 2 == 0 and a[1] % 2 != 0:\\n\\ts = a[1] * (a[0] // 2)\\nelif a[0] % 2 != 0 and a[1] % 2 == 0:\\n\\ts = a[0] * (a[1] // 2)\\nelif a[0] % 2 != 0 and a[1] % 2 != 0:\\n\\ts = a[1] * (a[0] // 2) + a[1] // 2\\nprint(s)\\n\",\n \"def domino():\\n\\t(M, N) = [int(i) for i in input().split()]\\n\\tX = M * N // 2\\n\\tprint(X)\\ndomino()\\n\",\n \"import math\\nmn = str.split(input())\\nm = int(mn[0])\\nn = int(mn[1])\\nif 1 <= m <= n <= 16:\\n\\tif m % 2 == 1:\\n\\t\\tx = math.floor(m / 2) * n\\n\\t\\ty = math.floor(n / 2)\\n\\t\\tprint(x + y)\\n\\telse:\\n\\t\\tx = int(m / 2 * n)\\n\\t\\tprint(x)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif M % 2 == 0:\\n\\tx = M // 2 * N\\nelif N % 2 == 0:\\n\\tx = N // 2 * M\\nelif M % 2 != 0 and N % 2 != 0:\\n\\tx = M // 2 * N + N // 2\\nprint(x)\\n\",\n \"import sys\\n(a, b) = map(int, sys.stdin.readline().split())\\ns = a // 2 * b\\nif a % 2 != 0:\\n\\ts += b // 2\\nprint(s)\\n\",\n \"inp = input().split()\\nprint(int(inp[0]) * int(inp[1]) // 2, sep='', end='\\\\n')\\n\",\n \"(m, n) = map(int, input().split())\\narea_of_domino = 2 * 1\\ndomino_number = 0\\nif m * n % 2 == 0:\\n\\tdomino_number = m * n / area_of_domino\\nelse:\\n\\tdomino_number = m * n // area_of_domino\\nprint(int(domino_number))\\n\",\n \"n = input()\\nm = n.split(' ')\\nx = int(m[0])\\ny = int(m[1])\\na = 2\\nprint(x * y // a)\\n\",\n \"w = input().split()\\na = int(w[0])\\nb = int(w[1])\\nc = a * b\\nd = int(c / 2)\\nprint(d)\\n\",\n \"(m, n) = [int(x) for x in input().split(' ')]\\nv = m // 2 * n + m % 2 * n // 2\\nh = n // 2 * m + n % 2 * m // 2\\nprint(max(h, v))\\n\",\n \"(a, b) = map(int, input().strip().split(' '))\\nz = int(a * b / 2)\\nprint(z)\\n\",\n \"import math\\ncode = input()\\n(a, b) = code.split(' ')\\na = int(a)\\nb = int(b)\\nresult = a * b // 2\\nresult = math.ceil(result)\\nprint(result)\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nx = m * n\\ny = math.floor(x / 2)\\nprint(y)\\n\",\n \"(m, n) = tuple(map(int, input().strip().split(' ')))\\nprint(m * n // 2)\\n\",\n \"try:\\n\\t(m, n) = list(map(int, input().split()))\\n\\tif (m >= 1) & (m <= n):\\n\\t\\tif n <= 16:\\n\\t\\t\\tprint(int(m * n / 2))\\nexcept ValueError as error:\\n\\tpass\\n\",\n \"(m, n) = map(int, input().split())\\nd = 2 * 1\\na = m * n\\nq = a // d\\nprint(q)\\n\",\n \"(a, s) = map(int, input().split())\\nd = a * s\\nprint(d // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split(' ')]\\nplaced = 0\\nif m >= 2 and n >= 1:\\n\\tplaceVertically = m // 2 * n\\n\\tverticalRemainder = m % 2\\n\\tif verticalRemainder:\\n\\t\\tplaceVertically += n // 2\\n\\tplaced = placeVertically\\nelif m >= 1 and n >= 2:\\n\\tplaceHorizontally = n // 2 * m\\n\\thorizontalRemainder = n % 2\\n\\tif horizontalRemainder:\\n\\t\\tplaceHorizontally += m // 2\\n\\tplaced = placeHorizontally\\nprint(placed)\\n\",\n \"import sys\\nfrom math import sqrt\\ninp = sys.stdin.readline\\nread = lambda : list(map(int, inp().split()))\\n\\ndef solve():\\n\\t(m, n) = read()\\n\\tprint(m * n // 2)\\nsolve()\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ndomino = 2\\nif 1 <= m <= 16 and 1 <= n <= 16:\\n\\tboard = m * n\\n\\tans = board / domino\\n\\tprint(int(ans))\\n\",\n \"(i, k) = map(int, input().split())\\nprint(i * k // 2)\\n\",\n \"x = input()\\nlst = list(x.split(' '))\\nboard = 1\\nfor i in lst:\\n\\tboard *= int(i)\\nprint(int(board / 2))\\n\",\n \"(m, n) = list(map(int, input().strip().split(' ')))\\nif m == 1 or n == 1:\\n\\tprint(max(m, n) // 2)\\nelse:\\n\\tdominoes = m // 2\\n\\tdominoes *= n\\n\\tif m & 1:\\n\\t\\tdominoes += n // 2\\n\\tprint(dominoes)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\na = []\\na = [[1] * n for i in range(m)]\\ncounter = 0\\nfor i in range(m - 1):\\n\\tfor j in range(n):\\n\\t\\tif a[i][j] == 1 and a[i + 1][j] == 1:\\n\\t\\t\\tcounter += 1\\n\\t\\t\\ta[i][j] = 0\\n\\t\\t\\ta[i + 1][j] = 0\\nfor i in range(m):\\n\\tfor j in range(n - 1):\\n\\t\\tif a[i][j] == 1 and a[i][j + 1] == 1:\\n\\t\\t\\tcounter += 1\\n\\t\\t\\ta[i][j] = 0\\n\\t\\t\\ta[i][j + 1] = 0\\nprint(counter)\\n\",\n \"size = input().split(' ')\\nm = int(size[0])\\nn = int(size[1])\\nif m % 2 == 0:\\n\\tdominos = m / 2 * n\\nelif n % 2 == 0:\\n\\tdominos = n / 2 * m\\nelse:\\n\\tdominos = (m - 1) * n / 2 + (n - 1) / 2\\nprint(int(dominos))\\n\",\n \"import math\\ninput1 = input()\\nl1 = input1.split(' ')\\nl1 = [int(i) for i in l1]\\nans = l1[0] * l1[1] * 0.5\\nprint(math.floor(ans))\\n\",\n \"var = input()\\n(n, m) = map(int, var.split())\\ndom = 0\\nif n % 2 == 0:\\n\\tdom = n / 2 * m\\nelse:\\n\\tdom = n // 2 * m + m // 2\\nprint(int(dom))\\n\",\n \"result = 0\\ndomino_area = 0\\ninputs = input().split(' ')\\narea = int(inputs[0]) * int(inputs[1])\\nwhile True:\\n\\tif domino_area > area:\\n\\t\\tresult -= 1\\n\\t\\tbreak\\n\\tif domino_area == area:\\n\\t\\tbreak\\n\\telse:\\n\\t\\tresult += 1\\n\\t\\tdomino_area += 2\\nprint(result)\\n\",\n \"(l, b) = map(int, input().split())\\nt = l * b\\nif t % 2 == 0:\\n\\tO = t // 2\\nelse:\\n\\tt -= 1\\n\\tO = t // 2\\nprint(O)\\n\",\n \"(l, w) = [int(x) for x in input().split()]\\nprint(l * w // 2)\\n\",\n \"def dominos(x, y):\\n\\tif x % 2 == 0 or y % 2 == 0:\\n\\t\\treturn x * y / 2\\n\\telse:\\n\\t\\treturn ((x - 1) * (y - 1) + (x - 1) + (y - 1)) / 2\\n(m, n) = input().split(' ')\\nprint(int(dominos(int(m), int(n))))\\n\",\n \"import math\\n(n, k) = [int(x) for x in input().split()]\\nt = n * k\\nprint(t // 2)\\n\",\n \"(m, n) = map(int, input().strip().split())\\nsol = int(n / 2) * m\\nif n % 2 != 0:\\n\\tsol = sol + int(m / 2)\\nprint(sol)\\n\",\n \"def _50A(m, n):\\n\\treturn m * n // 2\\n(m, n) = list(map(lambda x: int(x), input().split()))\\nprint(_50A(m, n))\\n\",\n \"(m, n) = map(int, input().split())\\ncount = 0\\nwhile m - 2 >= 0:\\n\\tcount += 1\\n\\tm -= 2\\ncount *= n\\nif m != 0:\\n\\twhile n - 2 >= 0:\\n\\t\\tcount += 1\\n\\t\\tn -= 2\\nprint(count)\\n\",\n \"(x, y) = [int(x) for x in input().split()]\\nans = x * y / 2\\nprint(int(ans))\\n\",\n \"n = input().split(' ')\\nfor i in range(2):\\n\\tn[i] = int(n[i])\\nprint(int(n[0] * n[1] / 2))\\n\",\n \"Cadena = input()\\nL = Cadena.split()\\nM = int(L[0])\\nN = int(L[1])\\nif N % 2 == 0:\\n\\tprint(N // 2 * M)\\nelse:\\n\\tprint(N // 2 * M + M // 2)\\n\",\n \"dx = 1\\ndy = 2\\n(m, n) = map(lambda x: int(x), input().split(' '))\\nif m < 0 or n < 0:\\n\\tprint(0)\\n\\texit(-1)\\nprint(int(m * n / 2))\\n\",\n \"(a, b) = (int(x) for x in input().split())\\ni = 0\\nif a % 2 == 1 and b % 2 == 1:\\n\\ta -= 1\\n\\ti = 1\\nn = a * b // 2\\nprint((n, n + b // 2)[i > 0])\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif M % 2 == 0:\\n\\tans = M // 2 * N\\nelse:\\n\\tans = M // 2 * N + N // 2\\nprint(ans)\\n\",\n \"(x, y) = map(int, input().split())\\nc = int(x * y // 2)\\nprint(c)\\n\",\n \"nm = input().rstrip().split()\\nn = int(nm[0])\\nm = int(nm[1])\\nprint(int(n * m / 2))\\n\",\n \"from math import floor\\n\\ndef main():\\n\\t(m, n) = map(int, input().split())\\n\\ta = m * n\\n\\tprint(floor(a / 2))\\nmain()\\n\",\n \"q = list(map(int, input().split()))\\nM = q[0]\\nN = q[-1]\\nprint(N * M // 2)\\n\",\n \"a = [int(x) for x in input().split()]\\nm = a[0]\\nn = a[1]\\nl = m * n\\nif l % 2 == 0:\\n\\tprint(int(l / 2))\\nelse:\\n\\tprint(int((l - 1) / 2))\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\np = area // 2\\nprint(p)\\n\",\n \"a = [int(i) for i in input().split()]\\nm = a[0]\\nn = a[1]\\nans = int(int(m * n) / 2)\\nprint(str(ans))\\n\",\n \"M = list(map(int, input().split()))\\nm = M[0]\\nn = M[1]\\na = m * n\\nb = a // 2\\nprint(b)\\n\",\n \"(m, n) = map(int, input().split())\\nm_max = max(m, n)\\nm_min = min(m, n)\\nres = m_max * (m_min // 2) + m_min % 2 * (m_max // 2)\\nprint(res)\\n\",\n \"import math\\narr = input().split(' ')\\nn = int(arr[0])\\nm = int(arr[1])\\nif n * m % 2 == 0:\\n\\tprint(int(n * m / 2))\\nelse:\\n\\tprint(int(math.floor(n * m / 2)))\\n\",\n \"(m, n) = tuple((int(it) for it in input().split()))\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nsize = m * n\\nnumOfDice = 0\\ndiceSpace = 0\\nwhile diceSpace <= size:\\n\\tnumOfDice += 1\\n\\tdiceSpace += 2\\nif diceSpace > size:\\n\\tdiceSpace -= 2\\n\\tnumOfDice -= 1\\nprint(numOfDice)\\n\",\n \"import math\\n\\ndef solve(m, n):\\n\\tprint(math.floor(m * n / 2))\\nx = list(map(int, input().split()))\\nsolve(x[0], x[1])\\n\",\n \"board_size = input().split(' ')\\nboard_size = int(board_size[0]) * int(board_size[1])\\nprint(board_size // 2)\\n\",\n \"import math\\n\\ndef main():\\n\\t(m, n) = [int(x) for x in input().split()]\\n\\tif m % 2 == 0 or n % 2 == 0:\\n\\t\\tprint(math.floor(m * n / 2))\\n\\telse:\\n\\t\\tprint(math.floor((m * n - 1) / 2))\\nmain()\\n\",\n \"m_n = input()\\nliste = m_n.split(' ')\\nm = int(liste[0])\\nn = int(liste[1])\\nminimum = min(m, n)\\nmaximum = max(m, n)\\nif maximum % 2 == 0:\\n\\tprint(maximum // 2 * minimum)\\nelse:\\n\\tprint(maximum // 2 * minimum + minimum // 2)\\n\",\n \"x = input()\\nz = x.split()\\nz = [int(i) for i in z]\\nx = z[0]\\ny = z[1]\\nprint(int(x * y / 2))\\n\",\n \"(a, b) = map(int, input().split())\\nn = a * b // 2\\nprint(n)\\n\",\n \"nm = input()\\narrinp = nm.split()\\nn = int(arrinp[0])\\nm = int(arrinp[1])\\nprint(n * m // 2)\\n\",\n \"import math\\ninput_list = input().split()\\na = int(input_list[0])\\nb = int(input_list[1])\\na_volumen = math.floor(a / 2)\\nb_volumen = a_volumen * b\\ngesamt_volumen = b_volumen\\nif a % 2 == 1:\\n\\tgesamt_volumen = b_volumen + math.floor(b / 2)\\nprint(int(gesamt_volumen))\\n\",\n \"from sys import stdin\\ninput = stdin.readline\\n\\ndef domin(m, n):\\n\\treturn n * (m >> 1) + (m & 1) * (n >> 1)\\nprint(domin(*map(int, input().split())))\\n\",\n \"input_data = input().split()\\nm = int(input_data[0])\\nn = int(input_data[1])\\ns = m * n // 2\\nprint(round(s))\\n\",\n \"def floor(n):\\n\\tres = int(n)\\n\\treturn res if res == n or n >= 0 else res - 1\\nline = input().split()\\nm = int(line[0])\\nn = int(line[1])\\nanswer = floor(m * n * 0.5)\\nprint(str(answer))\\n\",\n \"def main():\\n\\ti = input().split()\\n\\tprint(int(i[0]) * int(i[1]) // 2)\\nmain()\\n\",\n \"def dominoes(table):\\n\\treturn int(table[0]) * int(table[1]) // 2\\nprint(dominoes(input().split(' ')))\\n\",\n \"MN = input().split()\\nA = int(MN[0]) * int(MN[1])\\na = 2\\nres = 0\\nwhile A >= a:\\n\\tA -= a\\n\\tres += 1\\nprint(int(res))\\n\",\n \"(m, n) = map(int, input().split())\\nprint([(n * m - 1) // 2, n * m // 2][m % 2 == 0 or n % 2 == 0])\\n\",\n \"sides = input()\\nlengths = sides.split(' ')\\na = int(lengths[0])\\nb = int(lengths[1])\\nif 1 <= a <= 16 and 1 <= b <= 16:\\n\\tarea = a * b\\n\\tdominocount = area // 2\\nprint(dominocount)\\n\",\n \"n = input().split()\\nd1 = int(n[0])\\nd2 = int(n[1])\\nm = d1 * d2\\nprint(m // 2)\\n\",\n \"import math\\ni = input().split()\\nr = 0\\nfor x in range(len(i)):\\n\\ti[x] = int(i[x])\\nn = i[0]\\nm = i[1]\\nr = math.floor(n / 2) * m + n % 2 * math.floor(m / 2)\\nprint(r)\\n\",\n \"sum = 0\\nline = input()\\n(M, N) = line.split()\\nm = int(M)\\nn = int(N)\\nx = m // 2\\nsum = sum + n * x\\nif m % 2 == 1:\\n\\tsum = sum + n // 2\\nprint(sum)\\n\",\n \"(m, n) = list(map(int, input('').split(' ')))\\ncount = 0\\nif m >= 1:\\n\\tif n % 2 != 0:\\n\\t\\tcount = n // 2 * m\\n\\t\\trem = n - n // 2\\n\\t\\tif rem >= 1:\\n\\t\\t\\tcount += m // 2\\n\\t\\tprint(count)\\n\\telse:\\n\\t\\tprint(n // 2 * m)\\nelse:\\n\\tprint(0)\\n\",\n \"p = input().split(' ')\\nif int(p[0]) >= 1 and int(p[0]) <= int(p[1]) and (int(p[1]) <= 16):\\n\\ta = int(p[0]) * int(p[1])\\n\\tif a == 1:\\n\\t\\tprint('0')\\n\\telif a >= 2:\\n\\t\\tb = int(a / 2)\\n\\t\\tprint(b)\\n\",\n \"l = list(map(int, input().split()))\\nm = l[0]\\nn = l[1]\\nto_num = m * n\\nprint(to_num // 2)\\n\",\n \"import math\\n(m, n) = [int(x) for x in input().split()]\\ns = m * n\\nd = 2 * 1\\nprint(math.floor(s / d))\\n\",\n \"def domino_piling():\\n\\tmn = str(input())\\n\\ti = mn.find(' ')\\n\\tm = int(mn[:i])\\n\\tn = int(mn[i + 1:])\\n\\tif m % 2 == 0 and n % 2 == 0:\\n\\t\\tprint(int(m * n / 2))\\n\\t\\treturn\\n\\tif m % 2 != 0 and n % 2 != 0:\\n\\t\\tprint(int(m * (n - 1) / 2 + (m - 1) / 2))\\n\\t\\treturn\\n\\tprint(int(m * n / 2))\\ndomino_piling()\\n\",\n \"[a, b] = [int(i) for i in input().split()]\\ns = a * b\\nkol = s // 2\\nprint(kol)\\n\",\n \"a = input().split(' ')\\nn = int(a[0])\\nk = int(a[1])\\nb = n * k\\nif b % 2 == 0:\\n\\tprint(int(b / 2))\\nelse:\\n\\tprint(int((b - 1) / 2))\\n\",\n \"mn = input().split()\\ns = int(mn[0]) * int(mn[1])\\nresult = s // 2\\nprint(result)\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\nt = 0\\nwhile t * 2 < n * m:\\n\\tif (t + 1) * 2 > n * m:\\n\\t\\tbreak\\n\\tt += 1\\nprint(t)\\n\",\n \"import math\\n\\ndef domino_piling(m, n):\\n\\tprint(int(m * n / 2))\\n(m, n) = map(int, input().split())\\ndomino_piling(m, n)\\n\",\n \"n = list(map(int, input().split()))\\nans = n[0] * n[1] // 2\\nprint(ans)\\n\",\n \"(l, w) = input().split()\\narea = int(l) * int(w)\\nif area % 2 == 0:\\n\\tans = int(area / 2)\\nelse:\\n\\tans = int((area - 1) / 2)\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split())\\nk = 0\\nl = 2\\nwhile m * n >= l:\\n\\tl += 2\\n\\tk += 1\\nprint(k)\\n\",\n \"(n, m) = input().strip('\\\\n\\\\r\\\\t ').split(' ')\\nn = int(n)\\nm = int(m)\\nif m % 2 == 1 and n % 2 == 1:\\n\\tprint((m * n - 1) // 2)\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"def domino_piling():\\n\\t(M, N) = input().split()\\n\\t(M, N) = (int(M), int(N))\\n\\tcount = M * N // 2\\n\\tprint(str(int(count)))\\ndomino_piling()\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\na = 2\\nb = 1\\ny = 0\\nz = 0\\nx = 0\\ny = m * n\\nz = a * b\\nx = y // z\\nprint(x)\\n\",\n \"def process(x, y):\\n\\treturn x * y // 2\\nn = [int(x) for x in input().split()]\\nx = process(n[0], n[1])\\nprint(x)\\n\",\n \"from __future__ import division, print_function\\nfrom fractions import Fraction\\nimport sys\\nimport os\\nfrom io import BytesIO, IOBase\\nfrom itertools import *\\nimport bisect\\nfrom heapq import *\\nfrom math import *\\nfrom copy import *\\nfrom collections import deque\\nfrom collections import Counter as counter\\nfrom itertools import combinations as comb\\nfrom itertools import permutations as permutate\\nfrom bisect import bisect_left as bl\\nfrom bisect import bisect_right as br\\nfrom bisect import bisect\\nBUFSIZE = 8192\\n\\nclass FastIO(IOBase):\\n\\tnewlines = 0\\n\\n\\tdef __init__(self, file):\\n\\t\\tself._fd = file.fileno()\\n\\t\\tself.buffer = BytesIO()\\n\\t\\tself.writable = 'x' in file.mode or 'r' not in file.mode\\n\\t\\tself.write = self.buffer.write if self.writable else None\\n\\n\\tdef read(self):\\n\\t\\twhile True:\\n\\t\\t\\tb = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))\\n\\t\\t\\tif not b:\\n\\t\\t\\t\\tbreak\\n\\t\\t\\tptr = self.buffer.tell()\\n\\t\\t\\t(self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr))\\n\\t\\tself.newlines = 0\\n\\t\\treturn self.buffer.read()\\n\\n\\tdef readline(self):\\n\\t\\twhile self.newlines == 0:\\n\\t\\t\\tb = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))\\n\\t\\t\\tself.newlines = b.count(b'\\\\n') + (not b)\\n\\t\\t\\tptr = self.buffer.tell()\\n\\t\\t\\t(self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr))\\n\\t\\tself.newlines -= 1\\n\\t\\treturn self.buffer.readline()\\n\\n\\tdef flush(self):\\n\\t\\tif self.writable:\\n\\t\\t\\tos.write(self._fd, self.buffer.getvalue())\\n\\t\\t\\t(self.buffer.truncate(0), self.buffer.seek(0))\\n\\nclass IOWrapper(IOBase):\\n\\n\\tdef __init__(self, file):\\n\\t\\tself.buffer = FastIO(file)\\n\\t\\tself.flush = self.buffer.flush\\n\\t\\tself.writable = self.buffer.writable\\n\\t\\tself.write = lambda s: self.buffer.write(s.encode('ascii'))\\n\\t\\tself.read = lambda : self.buffer.read().decode('ascii')\\n\\t\\tself.readline = lambda : self.buffer.readline().decode('ascii')\\n\\ndef print(*args, **kwargs):\\n\\t(sep, file) = (kwargs.pop('sep', ' '), kwargs.pop('file', sys.stdout))\\n\\tat_start = True\\n\\tfor x in args:\\n\\t\\tif not at_start:\\n\\t\\t\\tfile.write(sep)\\n\\t\\tfile.write(str(x))\\n\\t\\tat_start = False\\n\\tfile.write(kwargs.pop('end', '\\\\n'))\\n\\tif kwargs.pop('flush', False):\\n\\t\\tfile.flush()\\nif sys.version_info[0] < 3:\\n\\t(sys.stdin, sys.stdout) = (FastIO(sys.stdin), FastIO(sys.stdout))\\nelse:\\n\\t(sys.stdin, sys.stdout) = (IOWrapper(sys.stdin), IOWrapper(sys.stdout))\\nfrom types import GeneratorType\\n\\ndef iterative(f, stack=[]):\\n\\n\\tdef wrapped_func(*args, **kwargs):\\n\\t\\tif stack:\\n\\t\\t\\treturn f(*args, **kwargs)\\n\\t\\tto = f(*args, **kwargs)\\n\\t\\twhile True:\\n\\t\\t\\tif type(to) is GeneratorType:\\n\\t\\t\\t\\tstack.append(to)\\n\\t\\t\\t\\tto = next(to)\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\tstack.pop()\\n\\t\\t\\tif not stack:\\n\\t\\t\\t\\tbreak\\n\\t\\t\\tto = stack[-1].send(to)\\n\\t\\treturn to\\n\\treturn wrapped_func\\nmod = 1000000007\\n\\ndef inp():\\n\\treturn sys.stdin.readline().rstrip('\\\\r\\\\n')\\n\\ndef out(var):\\n\\tsys.stdout.write(str(var))\\n\\ndef lis():\\n\\treturn list(map(int, inp().split()))\\n\\ndef stringlis():\\n\\treturn list(map(str, inp().split()))\\n\\ndef sep():\\n\\treturn map(int, inp().split())\\n\\ndef strsep():\\n\\treturn map(str, inp().split())\\n\\ndef zerolist(n):\\n\\treturn [0] * n\\n\\ndef nextline():\\n\\tout('\\\\n')\\n\\ndef testcase(t):\\n\\tfor p in range(t):\\n\\t\\tsolve()\\n\\ndef printlist(a):\\n\\tfor p in range(0, len(a)):\\n\\t\\tout(str(a[p]) + ' ')\\n\\ndef solve():\\n\\t(m, n) = sep()\\n\\tans = m // 2 * n\\n\\tif m % 2 == 1:\\n\\t\\tans += n // 2\\n\\tprint(ans)\\nsolve()\\n\",\n \"(m, n) = input().split()\\nlength = int(m)\\nwiedth = int(n)\\ndomino = 0\\nif length % 2 == 0:\\n\\tdomino = length // 2 * wiedth\\nif wiedth % 2 == 0:\\n\\tdomino = wiedth // 2 * length\\nif length % 2 == 1:\\n\\tdomino = length // 2 * wiedth + wiedth // 2\\nif wiedth % 2 == 1:\\n\\tdomino = wiedth // 2 * length + length // 2\\nprint(domino)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0 and n % 2 == 0:\\n\\tres = m * n // 2\\nelif m % 2 == 1 and n % 2 == 1:\\n\\tres = (m - 1) * (n - 1) / 2 + m // 2 + n // 2\\nelse:\\n\\todd = m if m % 2 == 1 else n\\n\\teven = n if odd == m else m\\n\\tres = max(odd * even // 2, even * (odd // 2) + even // 2)\\nprint(int(res))\\n\",\n \"w = input()\\n(M, N) = w.split(' ')\\nif int(M) % 2 == 0 or int(N) % 2 == 0:\\n\\tr = int(M) * int(N) / 2\\nelse:\\n\\tr = (int(M) - 1) * int(N) / 2 + int(N) // 2\\nprint(int(r))\\n\",\n \"(M, N) = map(int, input().split())\\nt = M * N\\nif t % 2 == 1:\\n\\tt -= 1\\nprint(t // 2)\\n\",\n \"(M, N) = input().split()\\nm = int(M)\\nn = int(N)\\na = m * n\\nd = int(a / 2)\\nprint(d)\\n\",\n \"A = input().split()\\nz = A[0]\\nz = int(z)\\nx = A[1]\\nx = int(x)\\nq = x * z // 2\\nprint(q)\\n\",\n \"x = input()\\nz = x.split()\\nm = int(z[0])\\nn = int(z[1])\\nh = int(m * n // 2)\\nprint(h)\\n\",\n \"(squareH, squareL) = map(int, input().split())\\ndominoH = 1\\ndominoL = 2\\nif dominoH > dominoL:\\n\\t_tmp = dominoH\\n\\tdominoH = dominoL\\n\\tdominoL = _tmp\\nnumH = squareH // dominoH\\nnumL = squareL // dominoL\\nnumRotate = int()\\nrestL = squareL - numL * dominoL\\nif restL / dominoH > 0 and squareH / dominoL > 0:\\n\\tnumRotate = restL // dominoH * (squareH // dominoL)\\ntotal = numH + (numL - 1) * numH + numRotate\\nprint(total)\\n\",\n \"(m, n) = input().split()\\nif int(m) % 2 == 0:\\n\\tprint(int(int(m) / 2 * int(n)))\\nelse:\\n\\tt = int(int(m) / 2)\\n\\tp = int(int(n) / 2)\\n\\tprint(t * int(n) + p)\\n\",\n \"val = list(map(int, input().split(' ')))\\nprint(val[0] * val[1] // 2)\\n\",\n \"token = input()\\nasd = token.split()\\ntotal = int(asd[0]) * int(asd[-1])\\nprint(total // 2)\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\nnumber = 0\\nif M % 2 == 0:\\n\\tnumber = M // 2 * N\\nelse:\\n\\tnumber = M // 2 * N + N // 2\\nprint(number)\\n\",\n \"(M, N) = map(int, input().strip().split(' '))\\ndominos = M * N / 2\\nprint(int(dominos))\\n\",\n \"(m, n) = list(map(int, input().split(' ')))\\na = int(m / 2)\\na = a * n\\nif m % 2 == 1:\\n\\tb = int(n / 2)\\n\\ta = a + b\\nprint(a)\\n\",\n \"x = lambda : map(int, input().split())\\n(m, n) = x()\\nprint(int(m * n / 2))\\n\",\n \"(n, m) = [int(i) for i in input().split()]\\nts = n * m\\nprint(ts // 2)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\na = 2\\nif n >= m and n % 2 == 0:\\n\\tres = m * round(n / a)\\n\\tprint(res)\\nelif n >= m and n % 2 != 0:\\n\\tres = m * (n / a)\\n\\tprint(int(res))\\nelse:\\n\\tres = round(n / a) * round(m / a)\\n\\tprint(res)\\n\",\n \"(a, b) = map(int, input().split())\\nres = int(a * b / 2)\\nprint(res)\\n\",\n \"import sys\\n(n, m) = map(int, sys.stdin.read().rstrip().split())\\nprint(int(n * m // 2))\\n\",\n \"(largura, comprimento) = [int(i) for i in input().split()]\\nprint(int(largura * comprimento / 2))\\n\",\n \"first_line = input().split(' ')\\nM = int(first_line[0])\\nN = int(first_line[1])\\ndom_area = 2\\nboard_area = M * N\\nnum_of_dom = 0\\nif board_area % 2 == 0:\\n\\tnum_of_dom = board_area // dom_area\\nelse:\\n\\tnum_of_dom = (board_area - 1) // dom_area\\nprint(num_of_dom)\\n\",\n \"import math\\ns = input().split()\\nM = int(s[0])\\nN = int(s[1])\\nprint(math.floor(M * N / 2))\\n\",\n \"def letsee():\\n\\t(m, n) = map(int, input().split())\\n\\tif m < 1 or m > 16 or n < 1 or (n > 16):\\n\\t\\treturn\\n\\tdominos = m * n // 2\\n\\tprint(dominos)\\nletsee()\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ns = m * n\\nif s % 2 != 0:\\n\\ta = s - 1\\n\\td = int(a / 2)\\nelse:\\n\\td = int(s / 2)\\nprint(d)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nhasil = 0\\nluas = m * n\\nif luas % 2 == 0:\\n\\thasil = luas / 2\\nelse:\\n\\tluas = luas - 1\\n\\thasil = luas / 2\\nprint(round(hasil), '\\\\n')\\n\",\n \"def main():\\n\\tnumbers = input().split()\\n\\tn = int(numbers[0])\\n\\tm = int(numbers[1])\\n\\tres = n * m // 2\\n\\tprint(res)\\nmain()\\n\",\n \"masuk = list(map(int, input().split()))\\nA = masuk[0]\\nB = masuk[1]\\nhasil = int(A * B)\\nprint(int(hasil / 2))\\n\",\n \"luso = input()\\nM = int(luso.split(' ')[0])\\nN = int(luso.split(' ')[1])\\nk = 2\\nh = M * N\\nprint(h // k)\\n\",\n \"data = input()\\nminor_arr = str(data).split()\\nS = int(minor_arr[0]) * int(minor_arr[1])\\ncount = S // 2\\nprint(count)\\n\",\n \"(m, n) = map(int, input().split(' '))\\npiecearea = 2 * 1\\nrecarea = m * n\\nres = recarea / piecearea\\nres = int(res)\\nprint(res)\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ncnt = 0\\nif m % 2 == 0:\\n\\tcnt = cnt + m / 2 * n\\nelif n % 2 == 0:\\n\\tcnt = cnt + n / 2 * m\\nelse:\\n\\twhile n > 0:\\n\\t\\tcnt = cnt + m / 2\\n\\t\\tn = n - 1\\nprint(math.floor(cnt))\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\ntotal_area = M * N\\nprint(total_area // 2)\\n\",\n \"lst = list(input().strip().split())\\nm = int(lst[0])\\nn = int(lst[1])\\nprint(m * n // 2)\\n\",\n \"string = input().split()\\narea = int(string[0]) * int(string[1])\\nif area % 2 == 0:\\n\\tprint(area // 2)\\nelse:\\n\\tprint((area - area % 2) // 2)\\n\",\n \"(width, length) = map(int, input().split())\\n\\ndef is_even(num):\\n\\tif num % 2 == 0:\\n\\t\\treturn 'even'\\nif is_even(length):\\n\\tans = int(length / 2 * width)\\nelif is_even(width) and (not is_even(length)):\\n\\tans = int(width / 2 * length)\\nx = None\\ny = None\\nif width == 1 and length == 1:\\n\\tprint('0')\\n\\texit()\\nif not is_even(length) and (not is_even(width)):\\n\\tif width >= 2:\\n\\t\\tx = int(width / 2)\\n\\telif length >= 2:\\n\\t\\ty = int(length / 2)\\nif x is not None:\\n\\tdominoes_across = int(x * length)\\n\\trem = int(length / 2)\\n\\tans = dominoes_across + rem\\nif y is not None:\\n\\tdominoes_across = int(y * width)\\n\\trem = int(width / 2)\\n\\tans = dominoes_across + rem\\nprint(ans)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nprint(str(int(m * n / 2)))\\n\",\n \"(n, m) = map(int, input().split())\\narea = n * m\\narea2 = 2\\ncount = area // area2\\nprint(count)\\n\",\n \"push = lambda : map(int, input().split())\\n(n, m) = push()\\nprint(n * m // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nc = a * b\\nd = c\\nf = d - 1\\nif c % 2 == 0:\\n\\tt = int(c / 2)\\n\\tprint(t)\\nelse:\\n\\tprint(int(f / 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nres = m * n\\nout = int(res / 2)\\nprint(out)\\n\",\n \"(n, m) = map(int, input().split())\\nres = n * m\\nres2 = res // 2\\nprint(res2)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\tmax_tiles = m / 2 * n\\nelif n % 2 == 0:\\n\\tmax_tiles = n / 2 * m\\nelse:\\n\\tmax_tiles = m // 2 + n // 2 * m\\nprint(int(max_tiles))\\n\",\n \"def main():\\n\\t(M, N) = map(int, input().split())\\n\\tboardSize = M * N\\n\\tdominoSize = 2\\n\\tnumberOfDominus = int(boardSize / dominoSize)\\n\\tprint(numberOfDominus)\\nmain()\\n\",\n \"(m, n) = input().split()\\narea = int(m) * int(n)\\nnumber = area // (2 * 1)\\nprint(number)\\n\",\n \"(r, c) = map(int, input().split(' '))\\nnum = 0\\nif r % 2 == 0:\\n\\tnum = int(r / 2) * c\\nelse:\\n\\tnum = int(r / 2) * c + int(c / 2)\\nprint(num)\\n\",\n \"(m, n) = list(map(int, input().strip().split()))\\nanswer = m * n // 2\\nprint(answer)\\n\",\n \"temp = input().split(' ')\\nm = int(temp[0])\\nn = int(temp[1])\\nprint(m * n // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nif a * b % 2 == 0:\\n\\tprint(a * b // 2)\\nelse:\\n\\timport math\\n\\tprint(math.floor(a * b // 2))\\n\",\n \"def main(stuff):\\n\\t(m, n) = stuff\\n\\t(m, n) = (int(m), int(n))\\n\\tif m % 2 != 0 and n % 2 != 0:\\n\\t\\tprint(int((m * n - 1) / 2))\\n\\telse:\\n\\t\\tprint(int(m * n / 2))\\nmain(input().split())\\n\",\n \"lst_of_numbers = [int(x) for x in input().split()]\\nprint(lst_of_numbers[0] * lst_of_numbers[1] // 2)\\n\",\n \"(w, h) = map(int, input().split())\\nif w % 2 == h % 2 == 0:\\n\\tprint(int(w / 2 * h))\\nelif w % 2 == h % 2 == 1:\\n\\tprint(int((w - 1) / 2 * h + (h - 1) / 2))\\nelif not w % 2 == h % 2:\\n\\tprint(int(h * w / 2))\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\n(am, bm) = (a % 2, b % 2)\\nif am and bm:\\n\\tprint(int(((a - 1) * (b - 1) + a + b - 1) / 2))\\nif not am and (not bm):\\n\\tprint(int(a * b / 2))\\nif am and (not bm):\\n\\tprint(int(((a - 1) * b + b) / 2))\\nif not am and bm:\\n\\tprint(int((a * (b - 1) + a) / 2))\\n\",\n \"import math\\n(M, N) = input().split(' ')\\nM = int(M)\\nN = int(N)\\nprint(max(int(M / 2) * N + M % 2 * int(N / 2), int(N / 2) * M + N % 2 * int(M / 2)))\\n\",\n \"raw_arr = str(input()).split()\\n(m, n) = (int(raw_arr[0]), int(raw_arr[1]))\\ntiles = 0\\nif m % 2 == 1 and n % 2 == 1:\\n\\ttiles = (m * n - 1) / 2\\nelse:\\n\\ttiles = m * n / 2\\nprint(str(tiles)[:-2])\\n\",\n \"dimr = input().split()\\narea = int(dimr[0]) * int(dimr[1])\\nnumber = area / 2\\nreal_number = int(number)\\nprint(real_number)\\n\",\n \"__author__ = 'DeyerliQiz'\\n(n, m) = map(int, input().split())\\nprint(int(n * m / 2))\\n\",\n \"l = [int(i) for i in input().split()]\\nn1 = l[0]\\nn2 = l[1]\\ng = n1 * n2\\nprint(g // 2)\\n\",\n \"s = list(map(int, input().split()))\\nans = int(s[0] * s[1] / 2)\\nprint(ans)\\n\",\n \"(rows, cols) = list(map(int, input().split()))\\nprint(rows // 2 * cols + cols // 2 * (rows % 2))\\n\",\n \"(a, b) = [int(x) for x in input().strip().split()]\\ns = a * (b // 2) + b % 2 * (a // 2)\\nprint(s)\\n\",\n \"txt = input()\\n(m, n) = [int(i) for i in txt.split('\\\\n')[0].split(' ')]\\nprint(str(m * n // 2))\\n\",\n \"parameter = input()\\nm = int(parameter.split()[0])\\nn = int(parameter.split()[1])\\nnumber = m * n // 2\\nprint(number)\\n\",\n \"from sys import stdin, stdout\\ninp = [int(x) for x in stdin.read().split()]\\nm = inp.pop(0)\\nn = inp.pop(0)\\nprint(m * n // 2)\\n\",\n \"line = input()\\npieces = line.split()\\nM = int(pieces[0])\\nN = int(pieces[1])\\nif M * N % 2 == 0:\\n\\tn = int(M * N / 2)\\nelse:\\n\\tn = int((M * N - 1) / 2)\\nprint(n)\\n\",\n \"def Domino():\\n\\t(m, n) = input().split()\\n\\tif int(n) == 1:\\n\\t\\tprint(0)\\n\\telif int(n) % 2 == 0:\\n\\t\\tprint(int(n) // 2 * int(m))\\n\\telse:\\n\\t\\ta = int(n) // 2 * int(m)\\n\\t\\tb = int(m) // 2\\n\\t\\tprint(a + b)\\nDomino()\\n\",\n \"ar = list(map(int, input().split()))\\nprint(ar[0] * ar[1] // 2)\\n\",\n \"inp = input().strip().split()\\nm = int(inp[0])\\nn = int(inp[1])\\nif m % 2 == 0 and n % 2 == 0:\\n\\tmax1 = m // 2 * n\\n\\tmax2 = n // 2 * m\\n\\tif max1 > max2:\\n\\t\\tprint(max1)\\n\\telse:\\n\\t\\tprint(max2)\\nelif m % 2 == 0 and n % 2 != 0:\\n\\tprint(m // 2 * n)\\nelif m % 2 != 0 and n % 2 == 0:\\n\\tprint(n // 2 * m)\\nelse:\\n\\tmax1 = m // 2 * n + n // 2\\n\\tmax2 = n // 2 * m + m // 2\\n\\tif max1 > max2:\\n\\t\\tprint(max1)\\n\\telse:\\n\\t\\tprint(max2)\\n\",\n \"sides = input().split(' ')\\nprint(int(sides[0]) * int(sides[1]) // 2)\\n\",\n \"m_n = [int(i) for i in input().split()]\\nprint(m_n[0] * m_n[1] // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nArea = m * n\\ndomino = Area // 2\\nif m < 1 or m > 16 or n < 0 or (n > 19):\\n\\tpass\\nelse:\\n\\tprint(domino)\\n\",\n \"mn = list(map(int, input().rstrip().split()))\\nm = mn[0] * mn[1]\\nn = int(m / 2)\\nprint(n)\\n\",\n \"def main():\\n\\t(m, n) = [int(x) for x in input().split()]\\n\\tprint(int(m * n / 2))\\nmain()\\n\",\n \"(m, n) = [int(i) for i in input().split(' ')]\\n\\ndef recursive(result, curr_m):\\n\\tif curr_m > 2:\\n\\t\\treturn recursive(result + n, curr_m - 2)\\n\\telif curr_m == 2:\\n\\t\\treturn result + n\\n\\telse:\\n\\t\\treturn result + int(n / 2)\\nprint(recursive(0, m))\\n\",\n \"inp = input().split()\\n(m, n) = (int(inp[0]), int(inp[1]))\\nrow = m // 2\\nnum = row * n\\nif m % 2 == 1:\\n\\tnum += n // 2\\nprint(num)\\n\",\n \"s = input('')\\nl = s.split()\\nm = int(l[0])\\nn = int(l[1])\\na = m * n // 2\\nprint(a)\\n\",\n \"def max_dominoes(m, n):\\n\\tarea = m * n\\n\\tprint(area // 2)\\nline1 = input()\\narg1 = int(line1.split()[0])\\narg2 = int(line1.split()[1])\\nmax_dominoes(arg1, arg2)\\n\",\n \"import sys\\nfrom collections import Counter as C\\n(m, n) = map(int, input().split())\\nprint(m * n // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nS = M * N\\nif S % 2 == 1:\\n\\tnum = S // 2\\nelse:\\n\\tnum = S / 2\\nprint(int(num))\\n\",\n \"import math\\nnuminput = str(input())\\na = [int(x) for x in numinput.split()]\\nsize = a[0] * a[1] / 2\\nprint(math.floor(size))\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\nif s > 0 and s < 2:\\n\\tprint('0')\\nelif s >= 2:\\n\\tnumbers = int(s / 2)\\n\\tprint(numbers)\\n\",\n \"l = [input()]\\nl = l[0].split(' ')\\nm = int(l[0])\\nn = int(l[1])\\nprint(int(m * n / 4 * 2))\\n\",\n \"def f(m, n):\\n\\tc = 0\\n\\tc += m // 2 * n\\n\\tc += m % 2 * (n // 2)\\n\\treturn c\\n(m, n) = [int(i) for i in input().split()]\\nprint(f(m, n))\\n\",\n \"(sirka, vyska) = map(int, input().split())\\npoukladane = 0\\npoukladane += sirka * (vyska // 2)\\nif vyska % 2:\\n\\tpoukladane += sirka // 2\\nprint(poukladane)\\n\",\n \"from collections import Counter\\nimport string\\nimport math\\nimport sys\\n\\ndef array_int():\\n\\treturn [int(i) for i in sys.stdin.readline().split()]\\n\\ndef vary(number_of_variables):\\n\\tif number_of_variables == 1:\\n\\t\\treturn int(sys.stdin.readline())\\n\\tif number_of_variables >= 2:\\n\\t\\treturn map(int, sys.stdin.readline().split())\\n\\ndef makedict(var):\\n\\treturn dict(Counter(var))\\nmod = 100000007\\n(m, n) = vary(2)\\nans = 0\\nif n % 2 == 0:\\n\\tans += n // 2 * m\\nelse:\\n\\tans += m * (n - 1) // 2\\n\\tif m % 2 == 0:\\n\\t\\tans += m // 2\\n\\telse:\\n\\t\\tans += (m - 1) // 2\\nprint(ans)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\narea = m * n\\nprint(int(area / 2))\\n\",\n \"(m, n) = list(map(int, input().split(' ')))\\n(tmp1, tmp2, ans) = (0, 0, 0)\\ntmp1 = m // 2\\nans = tmp1 * n\\ntmp2 = m % 2\\nif tmp2 == 1:\\n\\tans += n // 2\\nprint(ans)\\n\",\n \"import math\\n(width, length) = list(map(int, input().split(' ')))\\nprint(math.floor(width * length / 2))\\n\",\n \"(a, b) = map(int, input().split())\\nc = a * b / (2 * 1)\\nprint(int(c))\\n\",\n \"import math\\ninput_dimensions = [int(x) for x in input().split(' ')]\\nprint(math.floor(input_dimensions[0] * input_dimensions[1] / 2))\\n\",\n \"nk = list(map(int, input().split()))\\nsquare = nk[0] * nk[1]\\nprint(square // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif n % 2 == 1 and m % 2 == 1:\\n\\tprint((n * m - 1) // 2)\\nelif n % 2 == 0 and m % 2 == 0:\\n\\tprint(n * m // 2)\\nelif n % 2 == 0 and m % 2 == 1:\\n\\tprint(n * m // 2)\\nelif n % 2 == 1 and m % 2 == 0:\\n\\tprint(m * n // 2)\\n\",\n \"(x, y) = map(int, input().split())\\nans = int(x / 2) * y\\nif not x % 2 == 0:\\n\\tans += int(y / 2)\\nprint(ans)\\n\",\n \"board_dimensions = input()\\nn = int(board_dimensions.split(' ')[0])\\nm = int(board_dimensions.split(' ')[1])\\nboard_size = n * m\\n\\ndef in_range(n, m):\\n\\treturn 1 <= n <= 16 and 1 <= m <= 16\\nif in_range(n, m) and board_size % 2 == 0:\\n\\tprint(int(board_size / 2))\\nelif in_range(n, m) and board_size % 2 != 0:\\n\\tprint(int(board_size / 2 - 0.5))\\nelse:\\n\\tprint('Number out of range')\\n\",\n \"x = input()\\nnumero = x.split(' ')\\nprint(int(numero[0]) * int(numero[1]) // 2)\\n\",\n \"a = input()\\nx = a.split()\\nn = int(x[0])\\nk = int(x[1])\\npdt = n * k\\nc = pdt / 2\\nc = int(c)\\nprint(c)\\n\",\n \"(m, n) = map(int, input().split())\\ndominoes_overlapped = m * n // 2\\nprint(str(dominoes_overlapped))\\n\",\n \"a = input()\\ns = ''\\nA = []\\nfor i in a:\\n\\tif i == ' ':\\n\\t\\tA.append(int(s))\\n\\t\\ts = ''\\n\\telse:\\n\\t\\ts += i\\nA.append(int(s))\\nif A[0] > A[1] or A[1] % 2 == 1:\\n\\ts = A[0]\\n\\tA[0] = A[1]\\n\\tA[1] = s\\nif A[0] * A[1] == 1:\\n\\tprint(0)\\nelif A[0] % 2 == 1 == A[1] % 2:\\n\\tprint(A[1] * (A[0] // 2) + A[1] // 2)\\nelif A[0] % 2 != A[1] % 2:\\n\\tprint(A[0] * (A[1] // 2))\\nelse:\\n\\tprint(A[0] * (A[1] // 2))\\n\",\n \"(m, n) = map(int, input().split())\\np = m * n\\ndominos = p // 2\\nprint(dominos)\\n\",\n \"import math\\n\\ndef toInteger(x):\\n\\tfor i in range(len(x)):\\n\\t\\tx[i] = int(x[i])\\n\\treturn x\\n\\ndef solve(x):\\n\\tsquares = x[0] * x[1]\\n\\treturn math.floor(squares / 2)\\nx = toInteger(input().split(' '))\\nprint(solve(x))\\n\",\n \"nm = input().split()\\nn = int(nm[0])\\nm = int(nm[1])\\nk = n * m\\nif k % 2 == 0:\\n\\tv = k // 2\\n\\tprint(v)\\nelse:\\n\\tj = (k - 1) // 2\\n\\tprint(j)\\n\",\n \"b = input()\\nb = b.split()\\nb1 = int(b[0])\\nb2 = int(b[1])\\nb3 = b1 * b2\\nrespuesta = b3 // 2\\nprint(respuesta)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nt1 = (m - m % 2) // 2 * n\\nt1 += m % 2 * ((n - n % 2) // 2)\\nt2 = (n - n % 2) // 2 * m\\nt2 += n % 2 * ((m - m % 2) // 2)\\nprint(max([t1, t2]))\\n\",\n \"def solve(m, n):\\n\\ta = m * n\\n\\treturn a // 2\\ninp = input().split(' ')\\nm = inp[0]\\nn = inp[1]\\nprint(solve(int(m), int(n)))\\n\",\n \"import math\\nstring = str(input()).split(' ')\\nm = int(string[0])\\nn = int(string[1])\\nprint(int(m / 2 * n / 1))\\n\",\n \"m = input().split()\\nM = int(m[0])\\nN = int(m[1])\\nS = M * N\\ns = S // 2\\nprint(s)\\n\",\n \"dimentions = [int(x) for x in input().split()]\\nlength = dimentions[0]\\nwidth = dimentions[1]\\narea = length * width\\ndinamo_pieces = int(area / 2)\\nprint(dinamo_pieces)\\n\",\n \"import math\\n(m, n) = (1, 1)\\n(m, n) = map(int, input().split())\\nd = 2\\nsum = 0\\nsq = m * n\\nif sq % 2 == 0:\\n\\tprint(int(sq / 2))\\nelse:\\n\\tprint(int((sq - 1) / 2))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ns = m * n\\nc = 0\\nfor i in range(1, s):\\n\\tif i * 2 <= s:\\n\\t\\tc = i\\n\\telse:\\n\\t\\tbreak\\nprint(c)\\n\",\n \"import math\\n\\ndef domino():\\n\\t(height, width) = list(map(int, input().split()))\\n\\tresult = math.floor(width / 2 * height)\\n\\treturn result\\nprint(domino())\\n\",\n \"s = input()\\ns = s.split(' ')\\nM = int(s[0])\\nN = int(s[1])\\nprint(M * N // 2)\\n\",\n \"given = input()\\nm = int(given.split(' ')[0])\\nn = int(given.split(' ')[1])\\nprint(n * m // 2)\\n\",\n \"import sys\\nimport math\\n\\ndef main():\\n\\t(m, n) = map(int, sys.stdin.readline().strip().split())\\n\\tprint(max(m, n) // 2 * min(m, n) + max(m, n) % 2 * min(m, n) // 2)\\nmain()\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nboard = m * n\\nif m >= 1 and m <= n and (n <= 16):\\n\\tdivision = board / 2\\n\\tMax = int(division)\\n\\tprint(Max)\\n\",\n \"var = input().split()\\nx = int(var[0])\\ny = int(var[1])\\narea = x * y\\nif area % 2 == 0:\\n\\tprint(int(area / 2))\\nelse:\\n\\tprint(int((area - 1) / 2))\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef invr():\\n\\treturn map(int, input().split())\\n\\ndef domino(v):\\n\\treturn v // 2\\n(m, n) = invr()\\no = domino(m * n)\\nprint(o)\\n\",\n \"inp = input()\\ns = inp.find(' ')\\nM = int(inp[:s])\\nN = int(inp[s + 1:])\\nprint(M * (N // 2) + M // 2 * (N % 2))\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\nDominos = M * N // 2\\nprint(Dominos)\\n\",\n \"board = list(map(int, input().split()))\\nSboard = board[0] * board[1]\\nprint(Sboard // 2)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nans = int(a / 2)\\nprint(ans)\\n\",\n \"x = list(map(int, input().strip().split()))\\na = x[0]\\nb = x[1]\\nprint(a * b // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nmilty = int(m * n)\\ndiv = milty // 2\\nprint(div)\\n\",\n \"(n, k) = map(int, input().split())\\nmultiplied = n * k\\nprint(multiplied // 2)\\n\",\n \"pl = list(map(int, input().split()))\\nluas = pl[0] * pl[1]\\nprint(luas // 2)\\n\",\n \"p = [i for i in input().split()]\\nfor i in range(len(p)):\\n\\tp[i] = int(p[i])\\nprint(p[0] * p[1] // 2)\\n\",\n \"n = list(map(int, input().split()))\\nif n[0] > n[1]:\\n\\ta = n[0]\\n\\tb = n[1]\\nelse:\\n\\ta = n[1]\\n\\tb = n[0]\\nif a % 2 == 0:\\n\\tprint(a // 2 * b)\\nelse:\\n\\tprint(a // 2 * b + b // 2)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nbourd = m * n\\nc = bourd / 2\\nprint(int(c))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m == 1 and n == 1:\\n\\tprint('0')\\nelif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\ts = m * n // 2\\n\\tprint(s)\\n\",\n \"(ms, ns) = input().split()\\nm = int(ms)\\nn = int(ns)\\narea = m * n\\ndom = area / 2\\ndominos = int(dom)\\nprint(dominos)\\n\",\n \"import sys, os.path\\nif os.path.exists('input.txt'):\\n\\tsys.stdin = open('input.txt', 'r')\\n\\tsys.stdout = open('output.txt', 'w')\\n(n, m) = map(int, input().split())\\nprint(m * n // 2)\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\nprint((M * N - 1) // 2 if M * N % 2 else M * N // 2)\\n\",\n \"(m, n) = map(int, input().split())\\n(a, r) = (0, 0)\\na = m * n\\nr = a // 2\\nprint(r)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nk = m / 1\\nl = n / 2\\nnum = math.floor(k * l)\\nprint(num)\\n\",\n \"from math import floor\\n\\ndef main():\\n\\tfrom sys import stdout\\n\\t(m, n) = map(int, input().split())\\n\\ttotal = m * n\\n\\tres = floor(total / 2)\\n\\tstdout.write(str(res))\\nmain()\\n\",\n \"size = list(map(int, input().split()))\\ns = size[0] * size[1] // 2\\nprint(s)\\n\",\n \"(m, n) = list(map(int, input().split(' ')))\\nlength = m\\nwidth = n\\nnumber = 0\\nif length < width:\\n\\tlength = n\\n\\twidth = m\\nwhile length != 1 or width != 1:\\n\\tif length < width:\\n\\t\\tmid = width\\n\\t\\twidth = length\\n\\t\\tlength = mid\\n\\tif length >= 2:\\n\\t\\tnumber += width * (length // 2)\\n\\t\\tlength = length % 2\\n\\t\\tif length == 0:\\n\\t\\t\\tbreak\\nprint(number)\\n\",\n \"(m, n) = list(map(int, input().split()))\\ncount = 0\\nif m >= 2:\\n\\trow = m\\n\\twhile row >= 2:\\n\\t\\tfor i in range(0, n):\\n\\t\\t\\tcount += 1\\n\\t\\trow -= 2\\n\\tif m % 2 != 0:\\n\\t\\tif n % 2 == 0:\\n\\t\\t\\tcount += n / 2\\n\\t\\telse:\\n\\t\\t\\tcount += (n - 1) / 2\\nelif n % 2 == 0:\\n\\tcount += n / 2\\nelse:\\n\\tcount += (n - 1) / 2\\nprint(int(count))\\n\",\n \"mn = list(map(int, input().rstrip().split()))\\n(m, n) = (mn[0], mn[1])\\narea_full = m * n\\narea_domino = 2 * 1\\nfactor = area_full // area_domino\\nprint(factor)\\n\",\n \"try:\\n\\t(m, n) = map(int, input().split())\\n\\tk = m * n\\n\\tprint(int(k // 2))\\nexcept:\\n\\tpass\\n\",\n \"inputs = list(map(int, input().split()))\\ncount = 0\\ncount += inputs[0] // 2\\ncount *= inputs[1]\\nif inputs[0] % 2 == 1:\\n\\tcount += inputs[1] // 2\\nprint(count)\\n\",\n \"(l, b) = map(int, input().split())\\ns = l * b / 2\\nprint(int(s))\\n\",\n \"(a, b) = map(int, input().split())\\nif a == 1 or b == 1:\\n\\tprint(max(a, b) // 2)\\nelse:\\n\\tprint(a * b // 2)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\ncard = 2 * 1\\ntotal = s // card\\nprint(total)\\n\",\n \"(w, y) = input().split()\\n(w, y) = [int(w), int(y)]\\na = w * y\\nprint(a // 2)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\na = 2\\ndomino = area // a\\nprint(domino)\\n\",\n \"(a, b) = map(int, input().split())\\nprint(a * b // 2, end='')\\n\",\n \"line = input()\\n(m, n) = [int(i) for i in line.split()]\\nif m < n:\\n\\tt = m\\n\\tm = n\\n\\tn = t\\nif m % 2 == 0:\\n\\ta = m // 2\\n\\ttotal = a * n\\nelse:\\n\\ta = m // 2\\n\\tb = n // 2\\n\\ttotal = a * n + b\\nprint(total)\\n\",\n \"import math\\nelem = input().split(' ')\\narea = int(elem[0]) * int(elem[1])\\nprint(math.floor(area / 2))\\n\",\n \"t = [int(e) for e in input().split()]\\nc = t[0] * t[1]\\nprint(c // 2)\\n\",\n \"inp = input(str())\\nnum = inp.split(' ')\\nm = int(num[0])\\nn = int(num[1])\\nno = m * n\\nposs = 0\\nif no % 2 == 0:\\n\\tposs = no / 2\\nelse:\\n\\tno -= 1\\n\\tposs = no / 2\\nprint(int(poss))\\n\",\n \"import math as ma\\n(l, b) = map(int, input().split())\\narea = l * b\\nprint(ma.floor(area / 2))\\n\",\n \"import math\\n(x, y) = [int(i) for i in input().split()]\\nanswer = 0\\nif x < 2:\\n\\tanswer = y / 2\\nelif y < 2:\\n\\tanswer = x / 2\\nelse:\\n\\tanswer = x * y / 2\\nprint(math.floor(answer))\\n\",\n \"data = [int(i) for i in input().split()]\\nprint(max(data[0] // 2 * data[1] + (data[1] // 2 if data[0] % 2 == 1 else 0), data[1] // 2 * data[0] + (data[0] // 2 if data[1] % 2 == 1 else 0)))\\n\",\n \"(m, n) = map(int, input().split())\\nds = abs(m * n / 2)\\nprint(int(ds))\\n\",\n \"def compute(w, h):\\n\\tif h == 1:\\n\\t\\treturn w // 2\\n\\tif w == 1:\\n\\t\\treturn h // 2\\n\\treturn h * (w // 2) + h // 2 * (w % 2)\\n(m, n) = [int(x) for x in input().split()]\\nprint(compute(m, n))\\n\",\n \"(n, h) = input().split(' ')\\nn = int(n)\\nh = int(h)\\nnum = h * n // 2\\nprint(num)\\n\",\n \"(m, n) = map(int, input().split())\\nmul = m * n\\nans = mul / 2\\nans = int(ans)\\nprint(ans)\\n\",\n \"s = input('')\\n(a, b) = s.split(' ', 1)\\nc = int(a)\\nd = int(b)\\nif c * d % 2 == 0:\\n\\tprint(int(c * d / 2))\\nelse:\\n\\te = c * d\\n\\tf = e - 1\\n\\tprint(int(f / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\npl = m * n\\ncl = pl / 2\\nprint(int(cl))\\n\",\n \"def solve(m, n):\\n\\tif m % 2 == 0:\\n\\t\\treturn int(m // 2 * n)\\n\\telif n % 2 == 0:\\n\\t\\treturn int(n // 2 * m)\\n\\telse:\\n\\t\\treturn int((m - 1) // 2 * (n - 1) + (m - 1) // 2 + (n - 1) // 2)\\n(m, n) = [int(i) for i in input().split(' ')]\\nprint(solve(m, n))\\n\",\n \"(w, h) = [int(i) for i in input().split()]\\ns = 0\\ni = 0\\nwhile i < w:\\n\\tfor t in range(h):\\n\\t\\tif w - i >= 2:\\n\\t\\t\\ts += 1\\n\\ti += 2\\nif i != w:\\n\\tt = 0\\n\\twhile t + 2 <= h:\\n\\t\\ts += 1\\n\\t\\tt += 2\\nprint(s)\\n\",\n \"l = input()\\nl = [int(x) for x in l.split()]\\nans = l[0] * l[1] // 2\\nprint(ans)\\n\",\n \"key_input = input().split(' ')\\nn = int(key_input[0])\\nm = int(key_input[1])\\nprint(int(n * m / 2))\\n\",\n \"(b, h) = map(int, input().split())\\nprint(b * h // 2)\\n\",\n \"class Domino:\\n\\n\\tdef solve(self, n, m):\\n\\t\\tresult = 0\\n\\t\\tif n * m % 2 == 0:\\n\\t\\t\\tresult = n * m / 2\\n\\t\\telse:\\n\\t\\t\\tresult = (n * m - 1) / 2\\n\\t\\treturn int(result)\\n(m, n) = map(int, input().split(' '))\\ndo = Domino()\\nprint(do.solve(n, m))\\n\",\n \"first = input().split(' ')\\ntotal = int(first[0]) * int(first[1])\\nprint(total // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nnum = m * n\\nif num % 2 == 0:\\n\\tnum1 = num / 2\\n\\tnum1 = int(num1)\\n\\tprint(num1)\\nelse:\\n\\tnum2 = (num - 1) / 2\\n\\tnum2 = int(num2)\\n\\tprint(num2)\\n\",\n \"(M, N) = list(map(int, input().split()))\\nnumber = M * N // 2\\nif M % 2 != 0 and N % 2 != 0:\\n\\tnumber = int(number)\\nprint(number)\\n\",\n \"dims = input()\\ndims = dims.split()\\nM = int(dims[0])\\nN = int(dims[1])\\nprint(int(M * N / 2))\\n\",\n \"(x, y) = map(int, input().split())\\nres = x * y\\nprint(int(res / 2))\\n\",\n \"def read_int():\\n\\treturn int(input().strip())\\n\\ndef read_ints():\\n\\treturn list(map(int, input().strip().split(' ')))\\n\\ndef solve():\\n\\t(M, N) = read_ints()\\n\\treturn M * N // 2\\nprint(solve())\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nmn = m * n\\nans = int(0)\\nif mn % 2 != 0:\\n\\tans = math.floor(mn / 2)\\nelse:\\n\\tans = mn / 2\\nans = int(ans)\\nprint(ans)\\n\",\n \"aa = list(map(int, input().split(' ')))\\na = aa[0]\\nb = aa[1]\\ndomino_Area = 2\\nsum_Rect = (a * b - 1) / domino_Area if a * b % 2 != 0 else a * b / domino_Area\\nprint(int(sum_Rect))\\n\",\n \"(l, b) = list(map(int, input().split()))\\nif l >= 1 and b >= l and (b <= 16):\\n\\tres = l * b // 2\\n\\tprint(res)\\n\",\n \"def DominoPiling():\\n\\tdimensions = input('').split(' ')\\n\\tarea = 1\\n\\tfor i in dimensions:\\n\\t\\tarea *= int(i)\\n\\tprint(int(area // 2))\\nDominoPiling()\\n\",\n \"import math, string, itertools, fractions, heapq, collections, re, array, bisect\\nfrom itertools import chain, dropwhile, permutations, combinations\\nfrom collections import defaultdict\\n\\ndef main(m, n):\\n\\tans = m * n // 2\\n\\tprint(ans)\\n\\ndef main_input(info=0):\\n\\t(m, n) = map(int, input().split())\\n\\tmain(m, n)\\nmain_input()\\n\",\n \"(num_1, num_2) = [int(i) for i in input().split()]\\nnum_squares = num_1 * num_2\\nif num_squares % 2 == 0:\\n\\tprint(num_squares // 2)\\nelse:\\n\\tprint((num_squares - 1) // 2)\\n\",\n \"import math\\n(a, b) = [int(x) for x in input().split()]\\nn = 2\\ns = a * b / 2\\nres = math.floor(s)\\nprint(res)\\n\",\n \"import math\\n(m, n) = (int(x) for x in input().split())\\nprint(math.floor(m * n * 0.5))\\n\",\n \"eersteInput = input()\\neersteInputSplitted = eersteInput.split()\\nm = int(eersteInputSplitted[0])\\nn = int(eersteInputSplitted[1])\\noppervlak = m * n\\naantal = int(oppervlak / 2)\\nprint(aantal)\\n\",\n \"(height, weight) = input().split(' ')\\nheight = int(height)\\nweight = int(weight)\\ns = height * weight\\nx = s % 2\\nanswer = (s - x) / 2\\nanswer = int(answer)\\nprint(answer)\\n\",\n \"x = input().split()\\nm = int(x[0])\\nn = int(x[1])\\nj = int(x[0]) * int(x[1]) // 2\\nprint(j)\\n\",\n \"x = list(map(int, input().split()))\\nif x[0] >= 1 and x[0] <= 16 and (x[1] >= 1) and (x[1] <= 16):\\n\\tr = x[0] * x[1]\\n\\tprint(int(r / 2))\\n\",\n \"(x, y) = map(int, input().split(' '))\\nres = x // 2 * y\\nif x % 2 != 0:\\n\\tres += y // 2\\nprint(res)\\n\",\n \"(m, n) = input().split()\\ndom = int(int(m) * int(n) / 2)\\nprint(dom)\\n\",\n \"f = [int(i) for i in input().split(' ')]\\nr = f[0] * f[1] // 2\\nprint(r)\\n\",\n \"size = input().split()\\nm = int(size[0])\\nn = int(size[1])\\nif m * n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelif m * n % 2 != 0:\\n\\te = m * n - 1\\n\\tprint(int(e / 2))\\n\",\n \"import math\\n(m, n) = [int(x) for x in input().split()]\\nif 16 >= n and n >= m and (m >= 1):\\n\\tprint(math.floor(n * m / 2))\\n\",\n \"s = input().split()\\nprint(eval(s[0]) * eval(s[1]) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nk = 0\\nfor i in range(m * n, 1, -2):\\n\\tk += 1\\nprint(k)\\n\",\n \"num = input().split()\\nn1 = int(num[0])\\nn2 = int(num[1])\\ncheck = n2 >= n1\\nif check:\\n\\tres = n1 * n2\\n\\tprint(res // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nimport math\\na = m * n / 2\\nb = math.floor(a)\\nprint(b)\\n\",\n \"(m, n) = map(int, input().split())\\nif m >= 1 and n >= 1 and (m * n % 2 == 0):\\n\\tx = m * n / 2\\n\\tx = int(x)\\n\\tprint(x)\\nelse:\\n\\ty = (m * n - 1) / 2\\n\\ty = int(y)\\n\\tprint(y)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nif m % 2 == 0:\\n\\tsm = m // 2 * n\\nelif m == 1:\\n\\tsm = n // 2\\nelse:\\n\\tsm = m // 2 * n + n // 2\\nprint(sm)\\n\",\n \"(M, N) = map(int, input().split())\\na = M * N\\nk = 0\\nif a % 2 != 0:\\n\\twhile a != 1:\\n\\t\\ta -= 2\\n\\t\\tk += 1\\nelse:\\n\\twhile a != 0:\\n\\t\\ta -= 2\\n\\t\\tk += 1\\nprint(k)\\n\",\n \"S = input()\\n(m, n) = map(int, S.split())\\nsum = int(m / 2) * n\\nif m % 2 == 1:\\n\\tsum += n / 2\\nprint(int(sum))\\n\",\n \"dat = input().split()\\na = int(dat[0])\\nb = int(dat[1])\\nif a % 2 == 1:\\n\\tif b % 2 == 1:\\n\\t\\tc = (a - 1) / 2\\n\\t\\td = (b - 1) / 2\\n\\t\\tn = 2 * c * d + c + d\\n\\telse:\\n\\t\\tn = a * b / 2\\nelse:\\n\\tn = a * b / 2\\nprint(int(n))\\n\",\n \"(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\ni = 2\\nz = 0\\nm = 1\\nk = 0\\nif y >= 2 and x >= y:\\n\\twhile i <= y:\\n\\t\\tz += 1\\n\\t\\ti += 2\\n\\ti = 2\\n\\tif y % 2 == 1:\\n\\t\\twhile i <= x:\\n\\t\\t\\tk += 1\\n\\t\\t\\ti += 2\\n\\tprint(x * z + k)\\nelif x >= 2 and x < y:\\n\\twhile i <= x:\\n\\t\\tz += 1\\n\\t\\ti += 2\\n\\ti = 2\\n\\tif x % 2 == 1:\\n\\t\\twhile i <= y:\\n\\t\\t\\tk += 1\\n\\t\\t\\ti += 2\\n\\tprint(y * z + k)\\nelif x == 1 or y == 1:\\n\\tif x == 1 and y >= 2:\\n\\t\\twhile y >= i:\\n\\t\\t\\tz += 1\\n\\t\\t\\ti += 2\\n\\tif y == 1 and x >= 2:\\n\\t\\twhile x >= i:\\n\\t\\t\\tz += 1\\n\\t\\t\\ti += 2\\n\\tprint(z)\\n\",\n \"def max_no_domino(m, n):\\n\\treturn m * n // 2\\n(m, n) = [int(x) for x in input().split()]\\nprint(max_no_domino(m, n))\\n\",\n \"cin = input().split(' ')\\n(m, n) = (int(cin[0]), int(cin[1]))\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelif m == 1 and n == 1:\\n\\tprint(0)\\nelif m == 1:\\n\\tprint(int(n / 2))\\nelif n == 1:\\n\\tprint(int(m / 2))\\nelse:\\n\\tprint(int(m / 2) * n + int(n / 2))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nif m % 2 == 1 and n % 2 == 1:\\n\\tprint((m * n - 1) // 2)\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"def domino(l, w):\\n\\tarea = int(l * w)\\n\\tpiece = int(2)\\n\\treturn int(area / piece)\\n(m, n) = map(int, input().split())\\nprint(domino(m, n))\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nx = m * n\\na = math.floor(x / 2)\\nprint(a)\\n\",\n \"inp = input().split()\\ninp = [int(i) for i in inp]\\nm = inp[0]\\nn = inp[1]\\ntotal = m * n\\nif total % 2 == 0:\\n\\tfinal = total // 2\\nelse:\\n\\tfinal = (total - 1) // 2\\nprint(final)\\n\",\n \"def domino(m, n):\\n\\tboard = m * n\\n\\tprint(board // 2)\\n(m, n) = map(int, input().split())\\ndomino(m, n)\\n\",\n \"import sys\\n\\ndef solution():\\n\\tline = input()\\n\\tm = int(line.split(' ')[0])\\n\\tn = int(line.split(' ')[1])\\n\\tresult = 0\\n\\tif m < 2 and n < 2:\\n\\t\\tprint(result)\\n\\t\\treturn\\n\\tif m < 2:\\n\\t\\tresult = int(n / 2)\\n\\t\\tprint(result)\\n\\t\\treturn\\n\\tif n < 2:\\n\\t\\tresult = int(m / 2)\\n\\t\\tprint(result)\\n\\t\\treturn\\n\\tresult = n * int(m / 2)\\n\\tif m % 2 != 0:\\n\\t\\tresult += int(n / 2)\\n\\tprint(result)\\nsolution()\\n\",\n \"arr = list(map(int, input().split()))\\nm = arr[0]\\nn = arr[1]\\nrect_area = m * n\\nstand_area = 2\\ndominos = int(rect_area / stand_area)\\nprint(dominos)\\n\",\n \"import math\\n(n, m) = input().split(' ')\\nn1 = int(n)\\nm1 = int(m)\\nprint(math.floor(n1 * m1 / 2))\\n\",\n \"def solve():\\n\\tarr = list(map(int, input().split()))\\n\\tm = arr[0]\\n\\tn = arr[1]\\n\\tprint(m * n // 2)\\nsolve()\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nprint([int((m * n - 1) * 0.5), int(m * n * 0.5)][m % 2 == 0 or n % 2 == 0])\\n\",\n \"(m, n) = list(map(int, input().split()))\\ns = m // 2 * n\\nif m & 1:\\n\\ts += n // 2\\nprint(s)\\n\",\n \"def watermelon():\\n\\tw = int(input())\\n\\tif w % 2 == 0:\\n\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\\ndef way_too_long_words():\\n\\tn = int(input())\\n\\twords = [input() for x in range(n)]\\n\\tfor word in words:\\n\\t\\tif len(word) > 10:\\n\\t\\t\\tprint(f'{word[0]}{len(word) - 2}{word[-1]}')\\n\\t\\telse:\\n\\t\\t\\tprint(word)\\n\\ndef team():\\n\\tn = int(input())\\n\\tv = [[int(x) for x in input().split()] for i in range(n)]\\n\\to = 0\\n\\tfor l in v:\\n\\t\\tif l.count(1) >= 2:\\n\\t\\t\\to += 1\\n\\tprint(o)\\n\\ndef next_round():\\n\\t(n, k) = map(int, input().split())\\n\\ts = [int(x) for x in input().split()]\\n\\to = 0\\n\\ti = s[k - 1]\\n\\tfor j in s:\\n\\t\\tif j >= i and j != 0:\\n\\t\\t\\to += 1\\n\\tprint(o)\\n\\ndef domino_piling():\\n\\timport math\\n\\t(m, n) = map(int, input().split())\\n\\to = 0\\n\\tif m * n < 2:\\n\\t\\tprint(0)\\n\\t\\texit()\\n\\tif m % 2 == 0:\\n\\t\\to = m * n / 2\\n\\telif n % 2 == 0:\\n\\t\\to = m * n / 2\\n\\telse:\\n\\t\\to = math.floor(m * n / 2)\\n\\tprint(int(o))\\ndomino_piling()\\n\",\n \"t = input().split()\\n(a, b) = (int(t[0]), int(t[1]))\\nprint(a * b // 2)\\n\",\n \"def foo():\\n\\treturn 1\\n\\ndef main():\\n\\tfirst_line = input()\\n\\tfirst_line = first_line.split()\\n\\ta = int(first_line[0])\\n\\tb = int(first_line[1])\\n\\tprint(int(a * b / 2))\\nmain()\\n\",\n \"import math\\n(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nif a * b % 2 == 0:\\n\\tprint(int(a * b / 2))\\nelif a * b % 2 == 1:\\n\\tprint(int((a * b - 1) / 2))\\n\",\n \"x = input()\\nb = x.partition(' ')\\nprint(int(b[0]) * int(b[2]) // 2)\\n\",\n \"import math\\nlineArr = []\\n\\ndef intInput():\\n\\tglobal lineArr\\n\\tlineArr = input().split(' ')\\n\\tfor i in range(len(lineArr)):\\n\\t\\tlineArr[i] = int(lineArr[i])\\nintInput()\\nm = lineArr[0]\\nn = lineArr[1]\\n2\\nif n % 2 == 0:\\n\\td = n / 2 * m\\nelif m % 2 == 0:\\n\\td = m / 2 * n\\nelse:\\n\\td = math.floor(m * n / 2)\\nd = int(d)\\nprint(d)\\n\",\n \"(m, n) = [int(i) for i in str(input()).split(' ')[:2]]\\nif max(m, n) % 2 == 1:\\n\\tprint(min(m, n) * (max(m, n) // 2) + min(m, n) // 2)\\nelse:\\n\\tprint(min(m, n) * (max(m, n) // 2))\\n\",\n \"a = input().split()\\nif int(a[0]) % 2 == 0:\\n\\tprint(int(int(a[0]) / 2 * int(a[1])))\\nelif int(a[1]) % 2 == 0:\\n\\tprint(int(int(a[1]) / 2 * int(a[0])))\\nelse:\\n\\tprint(int((int(a[1]) * int(a[0]) - 1) / 2))\\n\",\n \"import math\\nw = input().split()\\ns = int(w[0])\\nc = int(w[1])\\nprint(s * c // 2)\\n\",\n \"(n, k) = map(int, input().split())\\nprint(str(int(n * k / 2)))\\n\",\n \"import math\\nline = input()\\nls = line.split(' ')\\narea = int(ls[0]) * int(ls[1])\\nprint(math.floor(area / 2))\\n\",\n \"def solution():\\n\\t(m, n) = [int(i) for i in input().split()]\\n\\tif m % 2 == 0 and n % 2 == 0:\\n\\t\\tprint(m * n // 2)\\n\\telif m % 2 == 0:\\n\\t\\tprint(m * (n // 2) + m // 2)\\n\\telif n % 2 == 0:\\n\\t\\tprint(n * (m // 2) + n // 2)\\n\\telse:\\n\\t\\tprint(n // 2 * (m // 2) * 2 + m // 2 + n // 2)\\nsolution()\\n\",\n \"(x, y) = input().split()\\ni = int(x)\\nj = int(y)\\nprint(i * j // 2)\\n\",\n \"(x, y) = input().split()\\nM = int(x)\\nN = int(y)\\nb = M * N // 2\\nprint(b)\\n\",\n \"from sys import stdin\\n\\ndef check(mask, i):\\n\\treturn bool(mask >> i & 1)\\n\\ndef add(mask, i):\\n\\tmask |= 1 << i\\n\\treturn mask\\n\\ndef remove(mask, i):\\n\\tmask &= ~(1 << i)\\n\\treturn mask\\n\\ndef main():\\n\\tline = stdin.readline\\n\\t(n, m) = map(int, line().split())\\n\\tif not n % 2 or not m % 2:\\n\\t\\tprint(n * m // 2)\\n\\telse:\\n\\t\\tprint(n // 2 * m + m // 2)\\nmain()\\n\",\n \"from sys import stdin\\n(lines, line_index) = (stdin.readlines(), -1)\\n\\ndef get_line():\\n\\tglobal lines, line_index\\n\\tline_index += 1\\n\\treturn lines[line_index]\\n\\ndef solve(m, n):\\n\\ta1 = m // 2 * n + m % 2 * n // 2\\n\\ta2 = n // 2 * m + n % 2 * m // 2\\n\\treturn max(a1, a2)\\n\\ndef main():\\n\\t(m, n) = [int(x) for x in get_line().split()]\\n\\tprint(solve(m, n))\\nmain()\\n\",\n \"y = input()\\nt = y.split(' ')\\ng = []\\nfor i in t:\\n\\tg.append(int(i))\\nd = g[0] * g[1]\\nprint(d // 2)\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\nd = math.floor(a * b / 2)\\nprint(d)\\n\",\n \"import sys\\n(n, m) = map(int, sys.stdin.readline().split())\\narea = n * m\\nprint(int(area / 2))\\n\",\n \"(m, n) = input().split()\\nprint('%i' % (int(m) * int(n) // 2))\\n\",\n \"import sys\\n(m, n) = map(int, input().split())\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nk = m * n\\nf = k // 2\\nprint(f)\\n\",\n \"a = input()\\na = a.split()\\nc = int(a[0]) * int(a[1])\\nc = c // 2\\nprint(c)\\n\",\n \"f = input().split()\\n(a, b) = [int(f[i]) for i in (0, 1)]\\nprint(str(a * b // 2))\\n\",\n \"size = [int(i) for i in input().split()]\\nif size[0] * size[1] % 2 == 0:\\n\\tprint(int(size[0] * size[1] / 2))\\nelse:\\n\\tprint(int((size[0] * size[1] - 1) / 2))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nnum = M * N\\nresult = num // 2\\nprint(result)\\n\",\n \"board = input().split(' ')\\nresult = int(board[0]) * int(board[1]) // 2\\nprint(result)\\n\",\n \"import math\\nfrom sys import stdin, stdout\\nnumbers = [int(x) for x in stdin.read().split()]\\ny = numbers.pop(0)\\nz = numbers.pop(0)\\ndimensions = y * z\\nprint(math.floor(dimensions / 2))\\n\",\n \"import math\\ns = list(map(int, input().split(' ')))\\np = s[0]\\nq = s[1]\\nprint(math.floor(p * q / 2))\\n\",\n \"(M, N) = map(int, input().split())\\na = M * N\\ni = 1\\nwhile i > 0:\\n\\tans = 2 * i\\n\\tif ans > a:\\n\\t\\tbreak\\n\\ti += 1\\nprint(i - 1)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nans = 0\\nans = int(ans + m * n / 2)\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m // 2 * n\\nif m % 2:\\n\\ts += n // 2\\nprint(s)\\n\",\n \"def solve(m, n):\\n\\tg = m if m > n else n\\n\\tl = m if m < n else n\\n\\treturn g * (l // 2) + g // 2 * (l % 2)\\n(m, n) = map(int, input().strip().split(' '))\\nprint(solve(m, n))\\n\",\n \"in1 = input().split()\\na = int(in1[0])\\nb = int(in1[1])\\np = a * b\\nif p % 2 == 0:\\n\\tprint(p // 2)\\nelse:\\n\\tprint((p - 1) // 2)\\n\",\n \"import sys\\nfor line in sys.stdin:\\n\\tparas = str(line).strip().split()\\n\\tm = int(paras[0])\\n\\tn = int(paras[1])\\n\\tprint(int(m * n / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\ttile = int(m / 2 * n)\\nelif n % 2 == 0:\\n\\ttile = int(n / 2 * m)\\nelse:\\n\\tm1 = m // 2\\n\\ttemp = m1 * n\\n\\tif m - m1 * 2 != 0:\\n\\t\\ttile = temp + n // 2\\n\\telse:\\n\\t\\ttile = temp\\nprint(tile)\\n\",\n \"(n, m) = map(int, input().split())\\na = n * m\\nif a % 2 == 0:\\n\\ts = a / 2\\nelse:\\n\\ts = a // 2\\nprint('{0:.0f}'.format(s))\\n\",\n \"board = list(map(int, input().split(' ')))\\nsquares = board[0] * board[1]\\nprint(int(squares / 2))\\n\",\n \"size = input()\\nlistsize = size.split()\\nm = int(listsize[0])\\nn = int(listsize[1])\\nif m >= 1 and m <= n and (n <= 16):\\n\\tarea = m * n\\n\\tif area % 2 != 0:\\n\\t\\tarea -= 1\\n\\tprint(int(area / 2))\\n\",\n \"S = [int(x) for x in input().split()]\\nN = S[1] * (S[0] // 2) + S[1] * (S[0] % 2) // 2\\nprint(N)\\n\",\n \"(width, height) = map(int, input().split())\\nif width * height % 2 == 1:\\n\\tprint(int((width * height - 1) / 2))\\nelse:\\n\\tprint(int(width * height / 2))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\ny = M * N // 2\\nprint(y)\\n\",\n \"(x, y) = map(int, input().split())\\nr_x = x // 2 * y\\nr_y = x % 2 * y // 2\\nprint(r_x + r_y)\\n\",\n \"(a, b) = map(int, input().split())\\narea = a * b\\ndomino = area // 2\\nprint(domino)\\n\",\n \"(n, m) = map(int, input().split())\\nh = m * n\\nd = 0\\nwhile h > 1:\\n\\th -= 2\\n\\td += 1\\nprint(d)\\n\",\n \"A = input()\\narr = list(map(int, A.split(' ')))\\na = arr[0]\\nb = arr[1]\\nc = a % 2\\nprint(int(a / 2) * b + c * int(b / 2))\\n\",\n \"class Scanner:\\n\\n\\tdef __init__(self):\\n\\t\\tself.current_tokens = []\\n\\n\\tdef remaining_tokens(self):\\n\\t\\treturn len(self.current_tokens)\\n\\n\\tdef nextline(self):\\n\\t\\tassert self.remaining_tokens() == 0, 'Reading next line with remaining tokens'\\n\\t\\treturn input()\\n\\n\\tdef nexttokens(self):\\n\\t\\treturn self.nextline().split()\\n\\n\\tdef nexttoken(self):\\n\\t\\tif len(self.current_tokens) == 0:\\n\\t\\t\\tself.current_tokens = self.nexttokens()\\n\\t\\treturn self.current_tokens.pop(0)\\n\\n\\tdef nextints(self):\\n\\t\\treturn list(map(int, self.nexttokens()))\\n\\n\\tdef nextint(self, n=1):\\n\\t\\treturn (int(self.nexttoken()) for i in range(n))\\nstdin = Scanner()\\nnextint = stdin.nextint\\nnextints = stdin.nextints\\nnextline = stdin.nextline\\n(m, n) = nextint(2)\\np = m * n\\nprint(p // 2)\\n\",\n \"data = input().split()\\nn = int(data[0])\\nm = int(data[1])\\nf = int(n * m / 4)\\nk = n * m - f * 4\\nf *= 2\\nif k >= 2:\\n\\tf += 1\\nprint(f)\\n\",\n \"import sys\\nfrom collections import Counter as C\\n(m, n) = map(int, input().split())\\nif not m & 1 or not n & 1:\\n\\tif not m & 1:\\n\\t\\tprint(m // 2 * n)\\n\\telif not n & 1:\\n\\t\\tprint(n // 2 * m)\\nelse:\\n\\tprint(m // 2 * n + n // 2)\\n\",\n \"(m, n) = input().split(' ')\\npiece = 0\\ni = 1\\nwhile i <= int(n):\\n\\tpiece += int(m) // 2\\n\\ti += 1\\nif int(m) % 2 != 0:\\n\\tpiece += int(n) // 2\\nprint(piece)\\n\",\n \"num1 = input().split(' ')\\nprint(int(int(num1[0]) * int(num1[1]) / 2))\\n\",\n \"def domino_piling(board_size_data):\\n\\tboard_size_list = board_size_data.split(' ')\\n\\tnum_rows = int(board_size_list[0])\\n\\tnum_cols = int(board_size_list[1])\\n\\tboard_area = num_rows * num_cols\\n\\treturn board_area // 2\\nboard_size_str = input()\\nnum_dominioes = domino_piling(board_size_str)\\nprint(num_dominioes)\\n\",\n \"def maximum_number(n, m):\\n\\tif n % 2 == 0 or m % 2 == 0:\\n\\t\\treturn int(n * m / 2)\\n\\treturn int((n - 1) * m / 2 + m // 2)\\n\\ndef main():\\n\\t(n, m) = tuple(map(int, input().split(' ')))\\n\\tresult = maximum_number(n, m)\\n\\tprint(result)\\nmain()\\n\",\n \"theInputString = input()\\ntheInputString = str.split(theInputString, ' ')\\n\\ndef getMaximumPlacement(x, y):\\n\\tif x <= 1 and y <= 1:\\n\\t\\treturn 0\\n\\tif x >= y:\\n\\t\\treturn x // 2 * y + getMaximumPlacement(x % 2, y)\\n\\telif y > x:\\n\\t\\treturn y // 2 * x + getMaximumPlacement(x, y % 2)\\ncounter = getMaximumPlacement(int(theInputString[0]), int(theInputString[1]))\\nprint(counter)\\n\",\n \"(m, n) = map(int, input().split())\\nadjusted_m = m\\nif m % 2 != 0:\\n\\tadjusted_m = m - 1\\nadjusted_n = n\\nif n % 2 != 0:\\n\\tadjusted_n = n - 1\\nnum = adjusted_m * adjusted_n // 2\\nif adjusted_m != m:\\n\\tnum += adjusted_n // 2\\nif adjusted_n != n:\\n\\tnum += adjusted_m // 2\\nprint(num)\\n\",\n \"raw_input = input().split(' ')\\nm = int(raw_input[0])\\nn = int(raw_input[1])\\ni = 1\\nnum = 0\\nwhile 2 * i <= m * n:\\n\\tif m * n > 1 and m * n <= 256:\\n\\t\\tnum = i\\n\\t\\ti = i + 1\\n\\telse:\\n\\t\\tnum = 0\\nprint(num)\\n\",\n \"def main():\\n\\t(m, n) = getInputs()\\n\\tif m % 2 == 0:\\n\\t\\ttotal = m // 2 * n\\n\\telif n % 2 == 0:\\n\\t\\ttotal = m * (n // 2)\\n\\telif m > 2:\\n\\t\\ttotal = m // 2 * n + n // 2\\n\\telif n > 2:\\n\\t\\ttotal = m * (n // 2) + m // 2\\n\\telse:\\n\\t\\ttotal = 0\\n\\tprint(round(total))\\n\\ndef getInputs():\\n\\t(m, n) = input().split()\\n\\treturn (int(m), int(n))\\nmain()\\n\",\n \"(rows, column) = [int(i) for i in input().split()]\\nif rows % 2 == 0 and column % 2 == 0:\\n\\tprint(column * (rows // 2))\\nelif rows % 2 != 0 and column % 2 != 0:\\n\\tif rows > column:\\n\\t\\tprint(column * (rows // 2) + column // 2)\\n\\telse:\\n\\t\\tprint(rows * (column // 2) + rows // 2)\\nelse:\\n\\teven = rows\\n\\todd = column\\n\\tif rows % 2 != 0:\\n\\t\\t(even, odd) = (odd, even)\\n\\tprint(odd * (even // 2))\\n\",\n \"def solve(m, n):\\n\\tboardarea = m * n\\n\\tdom_area = 2 * 1\\n\\treturn boardarea // dom_area\\n(m, n) = map(int, input().split(' '))\\nprint(solve(m, n))\\n\",\n \"t = input()\\n(m, n) = [int(x) for x in t.split()]\\nres = m * n\\nd = res // 2\\nprint(d)\\n\",\n \"(N, M) = input(' ').split()\\nN = int(N)\\nM = int(M)\\nnumber_of_dominos = M * N // 2\\nprint(number_of_dominos)\\n\",\n \"s = input()\\n(mm, nn) = s.split(' ')\\nm = int(mm)\\nn = int(nn)\\na = m * n // 2\\nprint(a)\\n\",\n \"import math\\ninp = input()\\nM = int(inp[0:2])\\nN = int(inp[2:5])\\nNN = 0\\ngap = 0\\nif M == 1 and N == 1:\\n\\tprint(0)\\nelse:\\n\\tif N / 2 == math.floor(N / 2):\\n\\t\\tNN = N\\n\\telse:\\n\\t\\tNN = N - 1\\n\\t\\tif M / 2 == math.floor(M / 2):\\n\\t\\t\\tgap = M\\n\\t\\telse:\\n\\t\\t\\tgap = M - 1\\n\\tprint(int(M * (NN / 2) + gap / 2))\\n\",\n \"line = input().split()\\nn = int(line[0])\\nm = int(line[1])\\npiece = int(m / 2) * n\\nif m % 2:\\n\\tpiece += int(n / 2)\\nprint(piece)\\n\",\n \"(a, y) = input().split()\\na = int(a)\\ny = int(y)\\nc = a * y\\nprint(c // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nout_value = m * n / 2\\nprint(int(out_value))\\n\",\n \"class Solution:\\n\\n\\tdef solve(self, m, n):\\n\\t\\treturn m * n // 2\\nsol = Solution()\\n[m, n] = list(map(int, input().strip().split()))\\nprint(sol.solve(m, n))\\n\",\n \"(k, n) = input().split()\\nk = int(k)\\nn = int(n)\\nc = k * n\\nf = c // 2\\nprint(f)\\n\",\n \"dim = [int(i) for i in input().split(' ')]\\nboard = dim[0] * dim[1]\\nans = board // 2\\nprint(ans)\\n\",\n \"line1 = input()\\nline = line1.split(' ', 2)\\ndimension = int(line[0]) * int(line[1])\\nif dimension % 2 == 0:\\n\\tprint(int(dimension / 2))\\nelse:\\n\\tprint(int((dimension - 1) / 2))\\n\",\n \"q = input()\\nw = q.split(' ')\\ne = []\\nfor i in w:\\n\\te.append(int(i))\\nr = e[0] * e[1]\\nprint(r // 2)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nt = m * int(n / 2)\\nif n % 2 != 0:\\n\\tt = t + int(m / 2)\\nprint(t)\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\nx = math.floor(a * b / 2)\\nprint(x)\\n\",\n \"nm = list(map(int, input().split()))\\nif nm[0] * nm[1] % 2 > 0:\\n\\ttotal = int(nm[0] * nm[1] / 2 - 0.5)\\nelse:\\n\\ttotal = int(nm[0] * nm[1] / 2)\\nprint(total)\\n\",\n \"(m, n) = map(int, input().split())\\ndom = 2\\nboard = m * n\\nresult = int(board / dom)\\nprint(result)\\n\",\n \"(m, n) = list(map(int, input().strip().split(' ')))\\nans = m * (n // 2)\\nif n % 2 == 0:\\n\\tprint(ans)\\nelse:\\n\\tans += m // 2\\n\\tprint(ans)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nL = m * n // 2\\nprint(L)\\n\",\n \"(n, m) = map(int, input().split())\\nc = m * n\\nli = []\\nif c % 2 == 1:\\n\\tli.append((c - 1) // 2)\\nelse:\\n\\tli.append(c // 2)\\nprint(li[0])\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nb = m * n // 2\\nprint(b)\\n\",\n \"input_text = input()\\nnm = input_text.split(' ')\\n(n, m) = (int(nm[0]), int(nm[1]))\\nnumber = int(n * m * 0.5)\\nprint(number)\\n\",\n \"(p, l) = map(int, input().split())\\nprint(int(p * l / 2))\\n\",\n \"(n, k) = input().split()\\nn = int(n)\\nk = int(k)\\nnum = 0\\nif n % 2 == 0 or k % 2 == 0:\\n\\tnum = int(n * k / 2)\\nelse:\\n\\tnum = int((n * k - 1) / 2)\\nprint(num)\\n\",\n \"(M, N) = map(int, input().split())\\nm = M // 2\\nif M % 2 == 0:\\n\\tprint(m * N)\\nelse:\\n\\tprint(m * N + N // 2)\\n\",\n \"mn = [int(n) for n in input().split()]\\nm = mn[0]\\nn = mn[1]\\nimport math\\nnum = n * math.floor(m / 2)\\nif m % 2 == 1:\\n\\tnum += math.floor(n / 2)\\nprint(num)\\n\",\n \"l = list(map(int, input().split()))\\na = l[0] * l[1]\\nn = a // 2\\nprint(n)\\n\",\n \"m_n = input().split()\\nsurface = int(m_n[0]) * int(m_n[1])\\nprint(surface // 2)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\na1 = 0\\nwhile b > 0:\\n\\tif a % 2 != 0 and b >= 2:\\n\\t\\ta1 += a\\n\\t\\tb -= 2\\n\\telif a % 2 == 0:\\n\\t\\ta1 += a // 2\\n\\t\\tb -= 1\\n\\telse:\\n\\t\\ta1 += a // 2\\n\\t\\tb = 0\\nprint(a1)\\n\",\n \"(m, n) = map(int, input().split())\\nnum = m // 2 * n\\nif m % 2 != 0:\\n\\tnum += n // 2\\nprint(num)\\n\",\n \"(m, n) = input().split()\\nmn = int(m) * int(n)\\nif mn % 2 == 0 and mn >= 2:\\n\\tans = mn / 2\\nelse:\\n\\tmn -= 1\\n\\tans = mn / 2\\nprint(round(ans))\\n\",\n \"import math\\nl = input().split(' ')\\n(M, N) = (int(l[0]), int(l[1]))\\nprint(int(M * N / 2))\\n\",\n \"(width, height) = input().split()\\nwidth = int(width)\\nheight = int(height)\\nprint(int(width * height / 2))\\n\",\n \"(m, n) = map(int, input().split())\\ndom = 2 * 1\\nboard = m * n\\nprint(board // dom)\\n\",\n \"mystr = input()\\nmystrL = mystr.split()\\nn = int(mystrL[1])\\nm = int(mystrL[0])\\nif n % 2 == 0:\\n\\tprint(int(n / 2 * m))\\nelif n % 2 != 0:\\n\\tprint(int(n // 2 * m + m // 2))\\n\",\n \"(m, n) = map(int, input().strip().split())\\nr = m * n\\nfor i in range(m * n):\\n\\tif i * 2 > r:\\n\\t\\tprint(i - 1)\\n\\t\\texit()\\n\\telif r == 1:\\n\\t\\tprint(0)\\n\\t\\texit()\\n\\telif r == 2:\\n\\t\\tprint(1)\\n\\t\\texit()\\n\",\n \"(n, m) = [int(i) for i in input().split(' ')]\\nsol = int(m / 2) * n + m % 2 * int(n / 2)\\nprint(sol)\\n\",\n \"(M, N) = map(int, input().split(' '))\\nif 1 <= M <= N <= 16:\\n\\ts = M * N\\n\\tprint(s // 2)\\n\",\n \"import sys\\nstring = input()\\ns = string.split(' ')\\nm = s[0]\\nn = s[1]\\nx = int(int(m) * int(n))\\nx = int(x / 2)\\nprint(x)\\n\",\n \"(x, y) = map(int, input().split())\\nans = x * y // 2\\nprint(ans)\\n\",\n \"import sys\\nrawdata = sys.stdin.read()\\ndata = list((int(n) for n in rawdata.split()))\\nboardSize = data[0] * data[1]\\nprint(int(boardSize / 2))\\n\",\n \"arr = list(map(int, input().rstrip().split()))\\nans = arr[0] * arr[1] // 2\\nprint(ans)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nS = 2\\nK = m * n // S\\nprint(K)\\n\",\n \"import sys\\n\\ndef get_vals(func=str):\\n\\treturn map(func, input().split())\\n\\ndef get(func=str):\\n\\treturn func(input())\\ninput = lambda : sys.stdin.readline().rstrip('\\\\r\\\\n')\\nwrite = sys.stdout.write\\n\\ndef test():\\n\\tpass\\n\\ndef main():\\n\\t(n, m) = get_vals(int)\\n\\tprint(n * m // 2)\\nmain()\\n\",\n \"coordinates = [int(i) for i in input().split()]\\ntotal_squares = coordinates[0] * coordinates[1]\\nprint(total_squares // 2)\\n\",\n \"import math as m\\nnum = input()\\nnum = num.split()\\nl = int(num[0])\\nw = int(num[-1])\\nprint(m.floor(l * w / 2))\\n\",\n \"def get_domino_amount(board):\\n\\tdomino_amount = 0\\n\\tfor i in range(len(board)):\\n\\t\\tfor k in range(len(board[i])):\\n\\t\\t\\tcurrent_item = board[i][k]\\n\\t\\t\\tif len(current_item) == 0:\\n\\t\\t\\t\\tif k < len(board[i]) - 1:\\n\\t\\t\\t\\t\\tnext_item = board[i][k + 1]\\n\\t\\t\\t\\t\\tif len(next_item) == 0:\\n\\t\\t\\t\\t\\t\\tdomino_amount += 1\\n\\t\\t\\t\\t\\t\\tcurrent_item.append('-')\\n\\t\\t\\t\\t\\t\\tnext_item.append('-')\\n\\t\\t\\t\\telif k == len(board[i]) - 1 and i < len(board) - 1:\\n\\t\\t\\t\\t\\tbelow_item = board[i + 1][k]\\n\\t\\t\\t\\t\\tif len(below_item) == 0:\\n\\t\\t\\t\\t\\t\\tdomino_amount += 1\\n\\t\\t\\t\\t\\t\\tcurrent_item.append('|')\\n\\t\\t\\t\\t\\t\\tbelow_item.append('|')\\n\\treturn domino_amount\\n\\ndef main():\\n\\t(m, n) = [int(i) for i in input().split()]\\n\\tboard = [[[] for k in range(m)] for i in range(n)]\\n\\tamount = get_domino_amount(board)\\n\\tprint(amount)\\nmain()\\n\",\n \"import math\\n(w, h) = [int(x) for x in input().split()]\\ndominos = math.floor(w / 2) * h\\nif w % 2 == 1:\\n\\tdominos += math.floor(h / 2)\\nprint(dominos)\\n\",\n \"import re\\ns = input()\\npl = re.split(' ', s)\\npl = [int(item) for item in pl]\\ns = pl[0] * pl[1]\\nprint(int(s / 2))\\n\",\n \"s = [int(i) for i in input().split()]\\nans = int(s[0] * s[1] / 2)\\nprint(ans)\\n\",\n \"(M, N) = map(int, input().split())\\nareaOfBoard = M * N\\nnumOfPieces = int(areaOfBoard / 2)\\nprint(numOfPieces)\\n\",\n \"size = input().split()\\na = int(size[0])\\nb = int(size[1])\\nprint(a * b // 2)\\n\",\n \"import math\\nn = input().split(' ')\\n(f, s) = (int(n[0]), int(n[1]))\\nprint(math.floor(f * s / 2))\\n\",\n \"(M, N) = map(int, input().split())\\np = M * N\\ns = int(p / 2)\\nprint(s)\\n\",\n \"import math\\na = [int(x) for x in input().split()]\\nm = a[0]\\nn = a[1]\\nif m % 2 == 0:\\n\\tprint(int(m / 2 * n))\\nelif n % 2 == 0:\\n\\tprint(int(n / 2 * m))\\nelse:\\n\\tprint(min(m, n) * math.floor(max(m, n) / 2) + math.floor(min(m, n) / 2))\\n\",\n \"lst = input().split()\\narea = int(lst[0]) * int(lst[1])\\nprint(area // 2)\\n\",\n \"x = input().split()\\nfor i in x:\\n\\tn = int(x[0])\\n\\tm = int(x[1])\\nL = n * m\\nmaks = L // 2\\nprint(maks)\\n\",\n \"(M, N) = list(map(int, input().strip().split()))\\nres = M * N // 2\\nprint(res)\\n\",\n \"(M, N) = tuple(map(int, input().split()))\\nlied = N // 2 * M + N % 2 * M // 2\\nstand = M // 2 * N + M % 2 * N // 2\\nprint(max(lied, stand))\\n\",\n \"(M, N) = input().split()\\ndomino_count = 0\\nfor n in range(0, int(N)):\\n\\tdomino_count += int(M) // 2\\nif int(M) % 2 == 1:\\n\\tdomino_count += int(N) // 2\\nprint(domino_count)\\n\",\n \"(n, m) = list(map(int, input().split()))\\ndominos = 0\\ndominos += n * (m // 2)\\nif m % 2 != 0:\\n\\tdominos += n // 2\\nprint(dominos)\\n\",\n \"grid = input('')\\nh = int(grid.split()[0])\\nw = int(grid.split()[1])\\nprint(str(h * w // 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nnumber = math.floor(m * n / 2)\\nprint(number)\\n\",\n \"import math\\nstr = input().split()\\nM = int(str[0])\\nN = int(str[1])\\nprint(N * M // 2)\\n\",\n \"import sys\\nfor line in sys.stdin:\\n\\tline = line.rstrip()\\n\\tline = line.split()\\n\\tline = list(map(int, line))\\n\\tprint(int(line[0] * line[1] / 2))\\n\",\n \"board = input('')\\nboard = board.split(' ')\\narea = int(board[0]) * int(board[1])\\nans = area // 2\\nprint(ans)\\n\",\n \"(a, b) = input().split()\\nwow = int(a) * int(b) // 2\\nprint(wow)\\n\",\n \"(m, n) = map(int, input().split())\\nif m // 2 >= n // 2:\\n\\tw = n // 2 * m\\n\\tw = (n * m - w * 2) // 2 + w\\nelse:\\n\\tw = m // 2 * n\\n\\tw = (n * m - w * 2) // 2 + w\\nprint(w)\\n\",\n \"(m, n) = map(int, input().split())\\ns = (n - n % 2) * (m - m % 2) // 2\\nif n % 2 == 1:\\n\\tif m % 2 == 1:\\n\\t\\ts += m // 2 + n // 2\\n\\telse:\\n\\t\\ts += m // 2\\nelif m % 2 == 1:\\n\\ts += n // 2\\nprint(s)\\n\",\n \"import math\\nx = input()\\nx = x.split()\\na = int(x[0])\\nb = int(x[1])\\nres = a * b / 2\\nprint(math.floor(res))\\n\",\n \"import sys\\ninput = sys.stdin.buffer.readline\\n\\ndef solution():\\n\\t(n, m) = map(int, input().split())\\n\\tprint(m * n // 2)\\nt = 1\\nfor _ in range(t):\\n\\tsolution()\\n\",\n \"board = input().split(' ')\\nM = int(board[0])\\nN = int(board[1])\\nboard_size = M * N\\ndomino = 2\\nprint(int(board_size / domino))\\n\",\n \"l = list(input().split())\\nm = int(l[0])\\nn = int(l[1])\\nboard = []\\nl1 = []\\nif m >= 1 and m <= n and (n <= 16):\\n\\tfor i in range(n):\\n\\t\\tfor j in range(m):\\n\\t\\t\\tl1.append(0)\\n\\t\\tboard.append(l1)\\n\\t\\tl1 = []\\n\\tsum = 0\\n\\tk = 0\\n\\tfor i in range(len(board)):\\n\\t\\tsum += len(board[i]) // 2\\n\\t\\tk = 0\\n\\t\\tfor j in range(0, len(board[i]) // 2):\\n\\t\\t\\tboard[i][k] = 1\\n\\t\\t\\tboard[i][k + 1] = 1\\n\\t\\t\\tk += 2\\n\\tfor i in range(0, len(board), 2):\\n\\t\\tif i == len(board) - 1:\\n\\t\\t\\tbreak\\n\\t\\telif board[i][len(board[i]) - 1] == 0 and board[i + 1][len(board[i]) - 1] == 0:\\n\\t\\t\\tsum += 1\\nprint(sum)\\n\",\n \"l = list(map(int, input().split()))\\nimport math\\nprint(math.trunc(l[0] * l[1] / 2))\\n\",\n \"count = 0\\nthe_string = input()\\n(x, y) = the_string.split()\\nx = int(x)\\ny = int(y)\\nif x >= 2:\\n\\tcount = y\\nz = int(x / 2)\\nif z > 1:\\n\\tcount = int(x / 2) * y\\nif x % 2 != 0:\\n\\tcount += int(y / 2)\\nprint(int(count))\\n\",\n \"(m, n) = map(int, input().split())\\nr = m * n\\ncount = 0\\ni = 0\\na_o_s = 2\\nwhile True:\\n\\ti += 1\\n\\ta_o_s = 2 * i\\n\\tif a_o_s > r:\\n\\t\\tbreak\\nprint(i - 1)\\n\",\n \"stroka = input().split()\\nm = int(stroka[0])\\nn = int(stroka[1])\\nk = 0\\nif n % 2 != 0:\\n\\tk = 1\\nprint(str(int((n - k) / 2 * m + int(k * m / 2))))\\n\",\n \"def can_fit(m, n, x=0, y=0):\\n\\tmove = 0\\n\\tif x + 2 <= m:\\n\\t\\tmove += can_fit(m, n, x + 2, y) + 1\\n\\telif y + 1 < n:\\n\\t\\tmove += can_fit(m, n, 0, y + 1)\\n\\treturn move\\n\\ndef domino_piling():\\n\\tx = input()\\n\\t(inp1, inp2) = x.split(' ')\\n\\tm = int(inp1)\\n\\tn = int(inp2)\\n\\tmove = can_fit(int(m), int(n))\\n\\tif m % 2 == 1:\\n\\t\\tmove += int(n / 2)\\n\\treturn move\\nprint(domino_piling())\\n\",\n \"(M, N) = map(int, input().split())\\nnbofDominos = 0\\nif M % 2 == 0:\\n\\tnbofDominos = M // 2 * N\\nelse:\\n\\tnbofDominos = M * N // 2\\nprint(nbofDominos)\\n\",\n \"rawInput = input().split()\\nm = int(rawInput[0])\\nn = int(rawInput[1])\\nprint(m * n // 2)\\n\",\n \"(m, n) = [int(_) for _ in input().split()]\\nif m > n:\\n\\ta = m\\n\\tm = n\\n\\tn = a\\nans = n // 2 * m + (m // 2 if n % 2 == 1 else 0)\\nprint(ans)\\n\",\n \"(a, b) = map(int, input().split())\\nc = a * b\\nif c % 2 == 0:\\n\\td = int(c / 2)\\n\\tprint(d)\\nelif c % 2 == 1:\\n\\td = c - 1\\n\\te = int(d / 2)\\n\\tprint(e)\\n\",\n \"list = input().split(' ')\\nnum_of_squares = int(list[0]) * int(list[1])\\ndominoes = num_of_squares // 2\\nprint(dominoes)\\n\",\n \"g = input()\\nwerte = g.split()\\nflaeche = int(werte[0]) * int(werte[1])\\nergebnis = flaeche / 2\\nprint(int(ergebnis))\\n\",\n \"(m, n) = map(int, input().split())\\nd = 2\\nres = m * n / 2\\nprint(int(res))\\n\",\n \"nums = list(map(int, input().split()))\\nprint(nums[0] * nums[1] // 2)\\n\",\n \"inp = input()\\n(row, col) = (int(x) for x in inp.split())\\ndomino = row * col * 0.5\\nprint(int(domino))\\n\",\n \"(m, n) = map(int, input().split())\\nt1 = m // 2 * (n // 1)\\nt2 = (m * n - t1 * 2) // 2\\nprint(t1 + t2)\\n\",\n \"(a, b) = map(int, input().split())\\nif a == 1 and b == 1:\\n\\tprint(0)\\nelse:\\n\\tn = max(a, b)\\n\\tm = min(a, b)\\n\\ts = 0\\n\\tif m > 1 and n % 2 != 0:\\n\\t\\ts = m // 2\\n\\tprint(m * (n // 2) + s)\\n\",\n \"mn = list(input().split())\\nm = int(mn[0])\\nn = int(mn[1])\\nquantityOfPlates = int(m * n / 2)\\nprint(int(quantityOfPlates))\\n\",\n \"a = str(input())\\nif len(a) < 5:\\n\\tif len(a) > 3:\\n\\t\\tif a[1] != ' ':\\n\\t\\t\\tx = a[0] + a[1]\\n\\t\\t\\ty = a[3]\\n\\t\\telse:\\n\\t\\t\\tx = a[0]\\n\\t\\t\\ty = a[2] + a[3]\\n\\telse:\\n\\t\\tx = a[0]\\n\\t\\ty = a[2]\\nelse:\\n\\tx = a[0] + a[1]\\n\\ty = a[3] + a[4]\\nz = int(y)\\nb = int(x)\\nprint(int(b * z / 2))\\n\",\n \"X = input().split(' ')\\nprint(int(int(X[0]) * int(X[1]) / 2))\\n\",\n \"(n, k) = map(int, input().split())\\ns = n * k\\ni = 0\\nc = 0\\nwhile abs(i - s) >= 2:\\n\\tc = c + 1\\n\\ti = i + 2\\nprint(c)\\n\",\n \"(M, N) = input().split()\\n(M, N) = (int(M), int(N))\\nans = M * N // 2\\nprint(ans)\\n\",\n \"(M, N) = list(map(int, input().split()))\\narea = M * N\\nmaxno = int(area / 2)\\nprint(maxno)\\n\",\n \"import math\\nimport itertools\\nimport os\\nimport sys\\nimport re\\nimport functools\\nimport operator\\nprint(functools.reduce(operator.mul, map(int, input().split())) // 2)\\n\",\n \"dimensions = list(map(int, str(input()).split(' ')))\\nm = dimensions[0]\\nn = dimensions[1]\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nmini = min(m, n)\\nmaxi = m + n - mini\\n\\ndef fun1(maxi, mini):\\n\\tcount = maxi // 2\\n\\tprint(count * mini)\\n\\ndef fun2(maxi, mini):\\n\\tcount = maxi // 2\\n\\tprint(count * mini + mini // 2)\\nif maxi % 2 == 0:\\n\\tfun1(maxi, mini)\\nelse:\\n\\tfun2(maxi, mini)\\n\",\n \"import math\\n\\ndef read_ints():\\n\\treturn map(int, input().split())\\nn = []\\nn = list(read_ints())\\nif n[0] % 2 == 0:\\n\\tans = n[1] * math.floor(n[0] / 2)\\nelse:\\n\\tans = n[1] * math.floor(n[0] / 2) + math.floor(n[1] / 2)\\nprint(ans)\\n\",\n \"import sys\\nimport math\\nn = list(map(int, sys.stdin.readline().split()))\\ncount = max(n) * math.floor(min(n) / 2)\\nif min(n) % 2 == 1:\\n\\tcount += math.floor(max(n) / 2)\\nprint(int(count))\\n\",\n \"(x, y) = (int(z) for z in input().split())\\nprint(int(x * y / 2))\\n\",\n \"import re\\nraw = input().split()\\ntotal = int(raw[0]) * int(raw[1])\\nprint(total // 2)\\n\",\n \"from array import array\\nfrom sys import stdin\\nimport bisect\\n\\ndef scan_gen():\\n\\tfor line in stdin:\\n\\t\\tyield from iter(line.split())\\nscan = scan_gen()\\n\\ndef nint():\\n\\treturn int(next(scan))\\n\\ndef nintk(k):\\n\\treturn tuple((nint() for _ in range(k)))\\n\\ndef nfloat():\\n\\treturn float(next(scan))\\n\\ndef intar_init(size):\\n\\treturn array('i', [0]) * size\\n\\ndef intar(size=None):\\n\\tarr = intar_init(size if size != None else nint())\\n\\tfor x in range(size):\\n\\t\\tarr[x] = nint()\\n\\treturn arr\\n\\ndef solve():\\n\\t(n, m) = nintk(2)\\n\\tprint(n * m // 2)\\nsolve()\\n\",\n \"from sys import stdin, stdout\\n\\ndef getInts():\\n\\treturn map(int, stdin.readline().split())\\n\\ndef main():\\n\\t(m, n) = getInts()\\n\\tans = m * n // 2\\n\\tprint(ans)\\nmain()\\n\",\n \"(a, b) = [int(a) for a in input().split()]\\nd = a * b\\nprint(d // 2)\\n\",\n \"lista = list(map(int, input().split()))\\ntotal = lista[0] * lista[1]\\nprint(int(total / 2))\\n\",\n \"(m, n) = [int(s) for s in input().split()]\\nif m * n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().strip().split())\\nprint(math.floor(m * n / 2))\\n\",\n \"(a, b) = input().split()\\n(a, b) = (int(a), int(b))\\nboard = a * b\\nprint(board // 2)\\n\",\n \"mn = input().split(' ')\\nba = int(mn[0]) * int(mn[1])\\nnum = int(ba / 2)\\nprint(num)\\n\",\n \"x_y = input()\\nxy = x_y.split()\\nxy = list(map(int, xy))\\ns = xy[0] * xy[1]\\nprint(s // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\tprint(str(m // 2 * n))\\n\\texit()\\nif n % 2 == 0:\\n\\tprint(str(n // 2 * m))\\n\\texit()\\ndominos_needed = 0\\ndominos_needed += m // 2\\ndominos_needed *= n\\ndominos_needed += n // 2\\nprint(dominos_needed)\\n\",\n \"from sys import stdin\\n(w_s, l_s) = stdin.readline().strip().split(' ')\\nl = int(l_s)\\nw = int(w_s)\\nif l % 2 == 1:\\n\\tnum_even_solns = int((l - 1) * w / 2)\\n\\tnum_odd_solns = int(w / 2)\\n\\tprint(num_even_solns + num_odd_solns)\\nelse:\\n\\tnum_even_solns = l * w / 2\\n\\tprint(int(num_even_solns))\\n\",\n \"from sys import stdin\\n(n, m) = stdin.readline().strip().split()\\nn = int(n)\\nm = int(m)\\nif m <= 16 and n <= 16:\\n\\tt = m * n // 2\\n\\tprint(t)\\n\",\n \"x = input()\\nl = x.split()\\nn = int(l[0])\\nm = int(l[1])\\nif m * n % 2 == 0:\\n\\tprint(m * n // 2)\\nelse:\\n\\ts = m * n - 1\\n\\tprint(s // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nprint(int(m / 2 * (n / 1)))\\n\",\n \"from math import floor\\ninp = input()\\nlis = inp.split()\\nm = int(lis[0])\\nn = int(lis[1])\\nlol = floor(m * n / 2)\\nprint(lol)\\n\",\n \"import math\\nvowel_list = ['a', 'e', 'i', 'o', 'u', 'y']\\n\\ndef watermelon_4a():\\n\\tnum = int(input())\\n\\tif num % 2 == 0:\\n\\t\\tif num == 2:\\n\\t\\t\\tprint('NO')\\n\\t\\telse:\\n\\t\\t\\tprint('YES')\\n\\telse:\\n\\t\\tprint('NO')\\n\\treturn\\n\\ndef theatre_square_1a():\\n\\tinput_list = read_list(int, input())\\n\\tlength = input_list[0]\\n\\twidth = input_list[1]\\n\\tflagstone = input_list[2]\\n\\tans_0 = int(math.ceil(length / flagstone))\\n\\tans_1 = int(math.ceil(width / flagstone))\\n\\tprint(ans_0 * ans_1)\\n\\treturn\\n\\ndef way_to_long_words_71a():\\n\\tcases = read_int()\\n\\tfor counter in range(cases):\\n\\t\\tword = input()\\n\\t\\tword_len = len(word)\\n\\t\\tif word_len <= 10:\\n\\t\\t\\tprint(word)\\n\\t\\telse:\\n\\t\\t\\tprint(word[0] + str(word_len - 2) + word[word_len - 1])\\n\\treturn\\n\\ndef next_round_158a():\\n\\tread_in = read_list(int, input())\\n\\tparticipant_scores = read_list(int, input())\\n\\ttotal_participants = read_in[0]\\n\\tfinish_place = read_in[1]\\n\\tcounter = 0\\n\\tif total_participants == 1:\\n\\t\\tif participant_scores[0] == 0:\\n\\t\\t\\tprint(0)\\n\\t\\telse:\\n\\t\\t\\tprint(1)\\n\\t\\treturn\\n\\telif participant_scores[finish_place - 1] == 0:\\n\\t\\tfor participant in participant_scores:\\n\\t\\t\\tif participant != 0:\\n\\t\\t\\t\\tcounter += 1\\n\\telse:\\n\\t\\tfor participant in participant_scores:\\n\\t\\t\\tif participant >= participant_scores[finish_place - 1]:\\n\\t\\t\\t\\tcounter += 1\\n\\tprint(counter)\\n\\treturn\\n\\ndef string_task_118a():\\n\\tstring = input()\\n\\tstring = string.lower().replace('a', '').replace('e', '').replace('i', '').replace('o', '').replace('u', '').replace('y', '')\\n\\tfinal_str = ''\\n\\tfor letter in string:\\n\\t\\tfinal_str += '.'\\n\\t\\tfinal_str += letter\\n\\tprint(final_str)\\n\\treturn\\n\\ndef domino_piling_50a():\\n\\tdimensions = read_list(int, input())\\n\\tlength = dimensions[0]\\n\\twidth = dimensions[1]\\n\\tprint(int(math.floor(length * width / 2)))\\n\\treturn\\n\\ndef read_list(type_in, line_in):\\n\\treturn list(map(type_in, line_in.split()))\\n\\ndef read_int():\\n\\treturn int(input())\\n\\ndef main():\\n\\tdomino_piling_50a()\\n\\treturn\\nmain()\\n\",\n \"a = input().split()\\nfor i in range(len(a)):\\n\\ta[i] = int(a[i])\\nd = a[0] * a[1]\\nh = d // 2\\nprint(h)\\n\",\n \"mas = input().split()\\nm = int(mas[0])\\nn = int(mas[1])\\nprint(int(m * n / 2))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nif m % 2 == 0 or n % 2 == 0:\\n\\tans = n * m / 2\\nelse:\\n\\tans = (n * m - 1) / 2\\nprint(int(ans))\\n\",\n \"(m, n) = map(int, input().split())\\nprod = m * n\\nresult = prod // 2\\nprint(result)\\n\",\n \"import math\\nx = input()\\ny = [int(i) for i in x.strip().split()]\\nprod = y[0] * y[1]\\nnum = prod // 2\\nprint(num)\\n\",\n \"i = iter((int(j) for j in input().split()))\\nprint(next(i) * next(i) // 2)\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\n\\ndef main(a, b):\\n\\tif a % 2 == 0:\\n\\t\\treturn a * b // 2\\n\\tif b % 2 == 0:\\n\\t\\treturn a * b // 2\\n\\treturn (a * b - 1) // 2\\nprint(main(a, b))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nsquare = M * N\\na = square / 2\\nprint(int(a))\\n\",\n \"def solve(m, n):\\n\\tarea = m * n\\n\\treturn (area - area % 2) // 2\\n(m, n) = map(int, input().split())\\nprint(solve(m, n))\\n\",\n \"X = input().split()\\nn = int(X[0])\\nm = int(X[1])\\nprint(n * m // 2)\\n\",\n \"def main():\\n\\t(n, m) = list(map(int, input().rstrip().split()))\\n\\tprint(n * m // 2)\\nmain()\\n\",\n \"numbers = input()\\nc = 0\\nfor i in range(len(numbers)):\\n\\tif numbers[i:i + 1] == ' ':\\n\\t\\tc = i\\nm = int(numbers[:c])\\nn = int(numbers[c + 1:])\\nif m % 2 != 0 or n % 2 != 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(m * n / 2))\\n\",\n \"l = input()\\n(n, m) = l.split()\\nn = int(n)\\nm = int(m)\\nres = 0\\nif n == m and n == 1:\\n\\tprint(0)\\nelse:\\n\\ts = n * m\\n\\tres = s // 2\\n\\tprint(res)\\n\",\n \"num = input()\\nx = num.split()\\nnum1 = int(x[0])\\nnum2 = int(x[1])\\nn = num1 * num2 * (1 / 2)\\nprint(int(n))\\n\",\n \"(m, n) = map(int, input().split())\\nt = 2 * 1\\nb = m * n\\nprint(int(b / t))\\n\",\n \"(a, b) = map(int, input().split())\\nif a < b:\\n\\ts = a\\n\\ta = b\\n\\tb = s\\nimport math\\nx = math.floor(a / 2) * b\\nif a % 2 == 0:\\n\\ty = 0\\nelse:\\n\\ty = math.floor(b / 2)\\nprint(x + y)\\n\",\n \"(m, n) = map(int, input().split())\\nsum = 0\\nx = m * n\\nwhile x > 1:\\n\\tx = x - 2\\n\\tsum = sum + 1\\nprint(sum)\\n\",\n \"import math\\n\\nclass Domino:\\n\\n\\tdef __init__(self, m, n):\\n\\t\\tself.m = m\\n\\t\\tself.n = n\\n\\n\\tdef max_domino(self):\\n\\t\\tp = m * n / 2\\n\\t\\treturn math.floor(p)\\n(m, n) = map(int, input().split())\\nk = Domino(m, n)\\na = k.max_domino()\\nprint(a)\\n\",\n \"inp = list(map(int, input().split()))\\nif inp[0] % 2 == 0:\\n\\tprint(int(inp[0] / 2 * inp[1]))\\nelse:\\n\\tanswer = inp[0] // 2 * inp[1]\\n\\tanswer += inp[1] // 2\\n\\tprint(answer)\\n\",\n \"(x, y) = input().split(' ')\\nx = int(x)\\ny = int(y)\\np = 0\\nif x >= 2 and y >= 1:\\n\\twhile x >= 2:\\n\\t\\tx = x - 2\\n\\t\\tz = y\\n\\t\\twhile y >= 1:\\n\\t\\t\\ty = y - 1\\n\\t\\t\\tp = p + 1\\n\\t\\ty = z\\n\\t\\tif x == 1:\\n\\t\\t\\tz = x\\n\\t\\t\\tx = y\\n\\t\\t\\ty = z\\nelif y >= 2 and x >= 1:\\n\\twhile y >= 2:\\n\\t\\ty = y - 2\\n\\t\\tz = x\\n\\t\\twhile x >= 1:\\n\\t\\t\\tx = x - 1\\n\\t\\t\\tp = p + 1\\n\\t\\tx = z\\n\\t\\tif y == 1:\\n\\t\\t\\tz = x\\n\\t\\t\\tx = y\\n\\t\\t\\ty = z\\nprint(p)\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nc = a * b\\nif a * b % 2 == 1:\\n\\tc = a * b - 1\\nprint(int(c / 2))\\n\",\n \"q = list(input().split(' '))\\nw = int(q[0]) * int(q[1])\\nprint(w // 2)\\n\",\n \"(a, b) = map(int, input().split())\\ncount = a // 2 * b\\nif a % 2 == 1:\\n\\tcount += b // 2\\nprint(count)\\n\",\n \"inp = input()\\n(m, n) = inp.split(' ')\\n(m, n) = (int(m), int(n))\\nflg = 2\\n(white, black) = (0, 0)\\nfor i in range(m * n):\\n\\tif flg % 2 == 0:\\n\\t\\tblack += 1\\n\\telse:\\n\\t\\twhite += 1\\n\\tflg += 1\\nprint(int((white + black) / 2))\\n\",\n \"(n, m) = map(int, input().split())\\nif n % 2 == 0 and m % 2 == 1:\\n\\tprint(n // 2 * m)\\nelif m % 2 == 0 and n % 2 == 1:\\n\\tprint(m // 2 * n)\\nelse:\\n\\tb = 1\\n\\tif n % 2 == m % 2 == 0:\\n\\t\\tprint(max(n // 2 * m, m // 2 * n))\\n\\t\\tb = 0\\n\\t(n, m) = (max(n, m) - 1, min(n, m))\\n\\tif b and n % 2 == 0 and (m % 2 == 1):\\n\\t\\tprint(n // 2 * m + m // 2)\\n\\telif b and m % 2 == 0 and (n % 2 == 1):\\n\\t\\tprint(m // 2 * n + n // 2)\\n\",\n \"(M, N) = map(int, input('').split())\\nA = M * N / 2\\nB = int(A)\\nprint(B)\\n\",\n \"import math\\n(m, n) = [int(x) for x in input().split()]\\nif m == 1 and n == 1:\\n\\tprint(0)\\nelse:\\n\\tprint(math.floor(m * n / 2))\\n\",\n \"n = input().split()\\nm = int(n[0])\\nn = int(n[1])\\na = [0] * 17\\na[1] = m // 2\\nfor i in range(m + 1):\\n\\ta[2] = max(a[2], i + (m - i) // 2 * 2)\\nfor i in range(n + 1):\\n\\tfor j in range(i, n + 1 - i):\\n\\t\\ta[i + j] = max(a[i + j], a[i] + a[j])\\nprint(a[n])\\n\",\n \"(m, n) = map(int, input().split())\\nk = n // 2\\np = n % 2\\nif p == 0:\\n\\ts = int(m * n / 2)\\nelse:\\n\\ts = int(m * k + m // 2)\\nprint(s)\\n\",\n \"data = input()\\n(m, n) = data.split()\\nm = int(m)\\nn = int(n)\\nanswer = 0\\nif m % 2 == 0 and n % 1 == 0:\\n\\tanswer = m * n // 2\\nelif m % 2 == 1 and n % 1 == 0:\\n\\tanswer = m * n // 2\\nprint(answer)\\n\",\n \"def main():\\n\\t(nrows, ncols) = map(int, input().strip().split())\\n\\tprint(nrows * ncols // 2)\\nmain()\\n\",\n \"mn = list(map(int, input().split()))\\nb = [[i for i in range(mn[0])] for i in range(mn[1])]\\nj = [len(i) for i in b]\\nprint(sum(j) // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nsq = M * N\\nansw = sq // 2\\nprint(answ)\\n\",\n \"n = list(map(lambda x: int(x), input().split()))\\nprint(n[0] * n[1] // 2)\\n\",\n \"import math\\n\\ndef DominoPiling(n, m):\\n\\treturn int(n * m / 2)\\npass\\n(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nprint(DominoPiling(n, m))\\n\",\n \"(M, N) = (int(x) for x in input().split())\\nremM = M % 2\\nremN = N % 2\\nif remM == 0 and remN == 0:\\n\\tmaxNumber = N * (M / 2)\\nelif remM == 0 and remN != 0:\\n\\tmaxNumber = M * (N // 2) + M / 2\\nelif remM != 0 and remN == 0:\\n\\tmaxNumber = N * (M // 2) + N / 2\\nelse:\\n\\tmaxNumber = M * (N // 2) + M // 2\\nprint(int(maxNumber))\\n\",\n \"import sys\\nimport math\\n\\ndef alele():\\n\\treturn list(map(int, sys.stdin.readline().strip().split()))\\n\\ndef ilele():\\n\\treturn map(int, sys.stdin.readline().strip().split())\\n\\ndef input():\\n\\treturn sys.stdin.readline().strip()\\n(A, B) = map(int, input().split(' '))\\nprint(A * B // 2)\\n\",\n \"str = input().split()\\nm = int(str[0])\\nn = int(str[1])\\nn_sqaures = 0\\nwhile m > 1 or n > 1:\\n\\tif m // 2 >= n // 2:\\n\\t\\tn_sqaures += m // 2 * n\\n\\t\\tm -= m // 2 * 2\\n\\telse:\\n\\t\\tn_sqaures += n // 2 * m\\n\\t\\tn -= n // 2 * 2\\nprint(n_sqaures)\\n\",\n \"import math\\n(l, m) = map(int, input().split())\\nprint(math.floor(m * l / 2))\\n\",\n \"h = input()\\ni = h.split(' ')\\nm = int(i[0])\\nn = int(i[1])\\nx = m * n // 2\\nprint(x)\\n\",\n \"ch = str(input())\\nL = ch.split()\\nLL = list()\\nfor c in L:\\n\\tLL.append(int(c))\\nL = LL\\nprint(L[0] * L[1] // 2)\\n\",\n \"area = []\\narea = input().split()\\nreslt = int(area[0]) * int(area[1]) / 2\\nprint(int(reslt))\\n\",\n \"entry = input()\\nentry = [int(i) for i in entry.split()]\\nn = entry[0]\\nm = entry[1]\\ndomino = n * m // 2\\nprint(domino)\\n\",\n \"def main():\\n\\tprint(eval('*'.join(input().split())) // 2)\\nmain()\\n\",\n \"numbers = input()\\nspace_ind = numbers.index(' ')\\nbord = int(numbers[:space_ind]) * int(numbers[space_ind:])\\nif bord % 2 == 0:\\n\\ttot = bord / 2\\nelse:\\n\\ttot = (bord - 1) / 2\\nprint(int(tot))\\n\",\n \"class main:\\n\\t(m, n) = input().split()\\n\\tmm = int(m)\\n\\tnn = int(n)\\n\\tsum = mm * nn\\n\\tres = sum // 2\\n\\tprint(format(res, '.0f'))\\n\",\n \"(M, N) = input().split(' ')\\nMaxDominoes = int(M) * int(N) // 2\\nprint(MaxDominoes)\\n\",\n \"(x, y) = map(int, input().split())\\narea = x * y\\nnumber = area // 2\\nprint(number)\\n\",\n \"line = input()\\npieces = line.split()\\na = int(pieces[0])\\nb = int(pieces[1])\\nprint(a * b // 2)\\n\",\n \"import math as ma\\ninp = tuple(input().split(' '))\\nprint(ma.floor(int(inp[0]) / 2 * int(inp[1])))\\n\",\n \"L = input().split()\\nM = int(L[0])\\nN = int(L[1])\\ntotal = M * N - M * N % 2\\nres = int(total / 2)\\nprint(res)\\n\",\n \"dimensions = list(map(int, input().strip().split()))\\narea = dimensions[0] * dimensions[1]\\nno_of_domino = area // 2\\nprint(no_of_domino)\\n\",\n \"input_size = input().split(' ')\\nn_k = [int(x) for x in input_size]\\nm = n_k[0]\\nn = n_k[1]\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int(m * ((n - 1) / 2) + (m - 1) / 2))\\n\",\n \"import math\\n(m, n) = [int(i) for i in input().split()]\\nif m % 2 == 0 or (m % 2 == 1 and n % 2 == 0):\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m - 1 + (n - 1) + (m - 1) * (n - 1)) / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\ndominoArea = 2 * 1\\nresult = math.floor(m * n / dominoArea)\\nprint(result)\\n\",\n \"def isEven(x):\\n\\tif x % 2 == 0:\\n\\t\\treturn True\\n(x, y) = [int(x) for x in input().split()]\\nif isEven(x) == True and isEven(y) == True:\\n\\tanswer = x * y / 2\\nelif isEven(x) == True and isEven(y) != True or (isEven(x) != True and isEven(y) == True):\\n\\tanswer = x * y / 2\\nelif isEven(x) != True and isEven(y) != True:\\n\\tanswer = x * y / 2 - 0.5\\nprint(int(answer))\\n\",\n \"(input_var1, input_var2) = input().split(' ')\\nvar1 = int(input_var1)\\nvar2 = int(input_var2)\\noutput = var1 * var2 // 2\\nprint(output)\\n\",\n \"(M, N) = input().split()\\nm = int(M)\\nn = int(N)\\nnum = 0\\nif m == 1:\\n\\tnum = n // 2\\nelif m % 2 == 0:\\n\\tnum = m / 2 * n\\nelif n % 2 == 0:\\n\\tnum = n / 2 * m\\nelif n == 1:\\n\\tnum = n // 2\\nelif m > n:\\n\\tnum = n * (m // 2) + n // 2\\nelse:\\n\\tnum = m * (n // 2) + m // 2\\nprint(int(num))\\n\",\n \"import math\\ninput_string = input().split()\\nn = int(input_string[0])\\nm = int(input_string[1])\\nprint(str(math.floor(n * m / 2)))\\n\",\n \"def domino(n, m):\\n\\treturn n * m // 2\\n(N, M) = [int(i) for i in input().split()]\\nprint(domino(N, M))\\n\",\n \"data = input().split()\\narea = int(data[0]) * int(data[1])\\nans = area // 2\\nprint(ans)\\n\",\n \"s = [int(i) for i in input().split(' ')]\\nk = s[1]\\nn = s[0]\\nprint(k * n // 2)\\n\",\n \"def fuck(a):\\n\\tk = a[0] * a[1]\\n\\ts = k // 2\\n\\tprint(s)\\na = [int(x) for x in input().split()]\\nfuck(a)\\n\",\n \"field = input().split(' ')\\nsquare = int(field[1]) * int(field[0])\\ndomino = square // 2\\nprint(domino)\\n\",\n \"from math import floor\\n\\ndef get_values():\\n\\ttry:\\n\\t\\tmeasurements = list(map(int, input().split()))\\n\\t\\t(m, n) = measurements\\n\\t\\tarea = m * n\\n\\t\\tArea_domino = 2\\n\\t\\tnum_dom = floor(area / Area_domino)\\n\\t\\treturn print(num_dom)\\n\\texcept ValueError:\\n\\t\\treturn\\nget_values()\\n\",\n \"a = list(map(int, input().split()))\\nif a[0] % 2 == 0 and a[1] % 2 == 0:\\n\\tprint(a[0] // 2 * a[1])\\nelif a[0] % 2 == 0 and a[1] % 2 == 1:\\n\\tprint(a[0] // 2 * a[1])\\nelif a[0] % 2 == 1 and a[1] % 2 == 0:\\n\\tprint(a[1] // 2 * a[0])\\nelse:\\n\\tprint(a[0] // 2 * a[1] + a[1] // 2)\\n\",\n \"first_input = input()\\nfirst_input1 = first_input.split()\\nM = int(first_input1[0])\\nN = int(first_input1[1])\\nmn = M * N\\nprint(int(mn / 2))\\n\",\n \"a = list(map(int, input().split()))\\nc = a[0] * a[1]\\nz = 0\\nif c % 2 == 0:\\n\\tfor i in range(0, c):\\n\\t\\tif i % 2 == 0:\\n\\t\\t\\tz += 1\\nelif c % 2 != 0:\\n\\tfor i in range(1, c):\\n\\t\\tif i % 2 == 0:\\n\\t\\t\\tz += 1\\nprint(z)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ns = 2 * 1\\na = m * n / s\\nprint(int(a))\\n\",\n \"import math\\nx = input().split()\\nn = int(x[0])\\nm = int(x[1])\\nprint(m * n // 2)\\n\",\n \"def main():\\n\\t(n, m) = map(int, input().split())\\n\\tans = n * m / 2\\n\\tprint(int(ans))\\nmain()\\n\",\n \"a = input()\\nspace = a.find(' ')\\nd = 0\\nif a[0:space] != '1' or a[space + 1:] != '1':\\n\\td = int(a[0:space]) * int(a[space + 1:]) // 2\\nprint(d)\\n\",\n \"a = input()\\n(m, n) = a.split(' ')\\n(m, n) = (int(m), int(n))\\nk = m * n\\nprint(k // 2)\\n\",\n \"import sys\\nterrain = list(map(int, sys.stdin.readline().split()))\\nprint(terrain[0] * terrain[1] // 2)\\n\",\n \"import sys\\nimport os\\nonline = 'ONLINE_JUDGE' in os.environ\\n\\ndef main():\\n\\t(m, n) = stdin_get_ints_from_line()\\n\\tprint(int(m / 2 * n))\\n\\treturn\\n\\ndef p(data):\\n\\tif not online:\\n\\t\\tprint(data)\\n\\ndef stdin_get_ints_from_line():\\n\\treturn (int(x) for x in sys.stdin.readline().strip().split(' '))\\n\\ndef stdin_get_ints_list_from_line():\\n\\treturn list((int(x) for x in sys.stdin.readline().strip().split(' ')))\\n\\ndef stdin_get_string_from_line():\\n\\treturn sys.stdin.readline().strip()\\nmain()\\n\",\n \"p = input().split()\\nM = int(p[0])\\nN = int(p[1])\\nn = int(M * N / 2)\\nprint(n)\\n\",\n \"a = input()\\na = a.split()\\nresult = [int(item) for item in a]\\nb = result[0]\\nc = result[1]\\nd = b * c // 2\\nprint(d)\\n\",\n \"mn = input()\\nh = mn.split()\\nA = int(h[0]) * int(h[1])\\nprint(int(A / 2))\\n\",\n \"values = [int(i) for i in input('').split(' ')]\\nprint(int(values[0] * values[1] / 2))\\n\",\n \"li = list(map(int, input().strip().split()))\\nm = li[0]\\nn = li[1]\\nc = m * n\\nc = c // 2\\nprint(c)\\n\",\n \"def main():\\n\\tarea = input().split()\\n\\tarea = int(area[0]) * int(area[1])\\n\\tif area % 2 == 1:\\n\\t\\tnodom = (area - 1) / 2\\n\\telse:\\n\\t\\tnodom = area / 2\\n\\tprint(int(nodom))\\nmain()\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0:\\n\\tif n % 2 == 0:\\n\\t\\tt = int(m * n / 2)\\n\\t\\tprint(t)\\n\\telse:\\n\\t\\tt = int(m / 2 * n)\\n\\t\\tprint(t)\\nelif n % 2 == 0:\\n\\tt = int(n / 2 * m)\\n\\tprint(t)\\nelse:\\n\\tt = int(m / 2)\\n\\tt1 = int(n / 2)\\n\\tprint(t * n + t1)\\n\",\n \"(m, n) = (int(i) for i in input().split())\\nh = m // 2\\ntotal = h * n\\nif m - h * 2 == 1 and n > 1:\\n\\ttotal += n // 2\\nprint(total)\\n\",\n \"import math\\nimport collections\\nimport bisect\\nimport heapq\\nimport time\\nimport random\\nimport itertools\\nimport sys\\n(N, M) = map(int, input().split())\\nif N % 2 == 1 and M % 2 == 1:\\n\\tprint((N * M - 1) // 2)\\nelse:\\n\\tprint(N * M // 2)\\n\",\n \"input_str = input().split(' ')\\na = int(input_str[0])\\nb = int(input_str[1])\\nres = a * b\\nprint(res // 2)\\n\",\n \"a = [int(i) for i in input().split()]\\nif a[0] % 2 == 0:\\n\\tn = 0.5 * a[0] * a[1]\\nelif a[1] % 2 == 0:\\n\\tn = 0.5 * a[0] * a[1]\\nelse:\\n\\tn = 0.5 * a[0] * a[1] - 0.5\\nprint(int(n))\\n\",\n \"x = list(map(int, input().split()))\\nr = x[0] * x[1]\\np = int(r / 2)\\nprint(p)\\n\",\n \"[M, N] = [int(i) for i in input().split()]\\nif M % 2 == 0:\\n\\tS = M / 2 * N\\nelif N % 2 == 0:\\n\\tS = N / 2 * M\\nelse:\\n\\tS = M // 2 * N + N // 2\\nprint(int(S))\\n\",\n \"field_args = input().split(' ')\\nn = int(field_args[0])\\nm = int(field_args[1])\\nprint(int((m * n - m * n % 2) / 2))\\n\",\n \"n = input().split()\\nc = int(n[0])\\nr = int(n[1])\\ncount = 0\\nncount = 0\\nfor i in range(r):\\n\\tif c % 2 != 0:\\n\\t\\tncount += 1\\n\\tfor x in range(1, c + 1):\\n\\t\\tif x % 2 == 0:\\n\\t\\t\\tcount += 1\\ncc = 0\\nfor i in range(1, ncount + 1):\\n\\tif i % 2 == 0:\\n\\t\\tcc = cc + 1\\nprint(count + cc)\\n\",\n \"def main():\\n\\tinfo = input().split()\\n\\tM = int(info[0])\\n\\tN = int(info[1])\\n\\treturn M * N // 2\\nprint(main())\\n\",\n \"def dominoPiling(m, n):\\n\\treturn m * n // 2\\n(m, n) = map(int, input().split())\\nprint(dominoPiling(m, n))\\n\",\n \"from sys import stdin\\n\\ndef main():\\n\\t(m, n) = stdin.readline().split()\\n\\tm = int(m)\\n\\tn = int(n)\\n\\ta = int(m / 2 * n)\\n\\tb = int(m * n / 2)\\n\\tif a < b:\\n\\t\\tprint(b)\\n\\telse:\\n\\t\\tprint(a)\\nmain()\\n\",\n \"import math\\ns = input().split()\\n(a, b) = (int(s[0]), int(s[1]))\\nresult = math.floor(a * b * 0.5)\\nprint(result)\\n\",\n \"(m, n) = map(int, input().split())\\nb = m * n\\nd = 2\\na = int(b / d)\\nprint(round(a))\\n\",\n \"line = input()\\ndimensions = line.split()\\nfor i in range(len(dimensions)):\\n\\tdimensions[i] = int(dimensions[i])\\nsquare = dimensions[0] * dimensions[1]\\nif square % 2 == 0:\\n\\tresult = int(square / 2)\\nelse:\\n\\tresult = int((square - 1) / 2)\\nprint(result)\\n\",\n \"(m, n) = map(int, input().strip().split(' '))\\ns = 2\\na = m * n\\nr = a // s\\nprint(r)\\n\",\n \"a = input().split()\\nl = int(a[0])\\nm = int(a[1])\\nprint(l * m // 2)\\n\",\n \"def main():\\n\\tinp = input().split()\\n\\t(m, n) = (int(inp[0]), int(inp[1]))\\n\\tMax = n // 2 * m + m // 2 * (n % 2) if n > m else m // 2 * n + n // 2 * (m % 2)\\n\\tprint(Max)\\nmain()\\n\",\n \"(a, b) = map(int, input().split())\\nif a == 1:\\n\\tprint(b // 2)\\nelif b == 1:\\n\\tprint(a // 2)\\nelif not a & 1:\\n\\tprint(a // 2 * b)\\nelif not b & 1:\\n\\tprint(b // 2 * a)\\nelse:\\n\\tprint(a * (b // 2) + a // 2)\\n\",\n \"(l, m) = [int(x) for x in input().split()]\\nc = 0\\nr = l * m\\nwhile r >= 2:\\n\\tc += 1\\n\\tr = r - 2\\nprint(c)\\n\",\n \"class DominoPiling:\\n\\n\\tdef solve(self, i, j):\\n\\t\\ttileArea = 2 * 1\\n\\t\\tboardArea = m * n\\n\\t\\treturn boardArea // tileArea\\n(m, n) = map(int, input().split(' '))\\nprint(DominoPiling().solve(m, n))\\n\",\n \"from math import floor\\n\\ndef domino():\\n\\t(m, n) = map(int, input().split())\\n\\tarea = m * n\\n\\tmaxd = floor(area / 2)\\n\\treturn maxd\\nprint(domino())\\n\",\n \"(a, b) = input().split()\\n(a, b) = (int(a), int(b))\\nmid = a * b\\nansw = mid // 2\\nprint(answ)\\n\",\n \"tempInput = input()\\nw = int(tempInput.split()[0])\\nh = int(tempInput.split()[1])\\nprint(int(w * h / 2))\\n\",\n \"n = input()\\nn1 = n.split()\\ns = int(n1[0]) * int(n1[1])\\nprint(s // 2)\\n\",\n \"width = 0\\nlength = 0\\nDominoWidth = 0\\nDominolength = 0\\na = 0\\n(width, length) = input().split()\\nwidth = int(width)\\nlength = int(length)\\nDominoWidth = int(width)\\nDominolength = int(length / 2)\\nif length % 2 != 0:\\n\\ta = 1\\nelse:\\n\\ta = 0\\nTotal = Dominolength * DominoWidth + a * int(width / 2)\\nprint(int(Total))\\n\",\n \"x = list(input().split())\\ntemp = int(x[0]) * int(x[1])\\nif temp % 2 != 0:\\n\\ttemp = temp - 1\\ntemp = int(temp / 2)\\nprint(temp)\\n\",\n \"(m, n) = map(int, input().split())\\nassert 0 <= m <= n <= 16\\nk = int(m * n / 2)\\nprint(k)\\n\",\n \"import math\\n(q, z) = input().split()\\nq = int(q)\\nz = int(z)\\nsp = q * z\\nn = math.floor(sp / 2)\\nprint(n)\\n\",\n \"from sys import stdin\\nA = list(map(int, stdin.readline().split()))\\nif A[0] % 2 == 0 or A[1] % 2 == 0:\\n\\tprint(int(A[0] * A[1] / 2))\\nelse:\\n\\tprint(int((A[0] * A[1] - 1) / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nw = max(m, n)\\nh = min(m, n)\\nres = h * (w // 2) + h // 2 * (w % 2)\\nprint(res)\\n\",\n \"from sys import stdin, stdout, exit as sys_ret\\n(f_input, f_print, f_flush) = (stdin.readline, stdout.write, stdout.flush)\\n(a, b) = map(int, f_input().split())\\nf_print(str(a * b // 2))\\n\",\n \"from math import floor as f\\nl = list(map(int, input().split()))\\nprint(f(l[0] * l[1] * 0.5))\\n\",\n \"n = input().split()\\na = int(n[0]) * int(n[1])\\nif a % 2 == 1:\\n\\tprint(int((a - 1) / 2))\\nelse:\\n\\tprint(int(a / 2))\\n\",\n \"(a, b) = map(int, input().split())\\narea = a * b\\na = area\\nif a & 1:\\n\\tprint((a - 1) // 2)\\nelse:\\n\\tprint(a // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nanswer = m * n // (2 * 1)\\nprint(answer)\\n\",\n \"string = input()\\nnumbers = string.split()\\n(a, b) = (int(numbers[0]), int(numbers[1]))\\nprint(a * b // 2)\\n\",\n \"temp = input().split()\\nn1 = int(temp[0])\\nn2 = int(temp[1])\\nn = n1 * n2\\nnum = int(n / 2)\\nprint(num)\\n\",\n \"a = [int(x) for x in input().split(' ')]\\nif a[0] % 2 == 0 or a[1] % 2 == 0:\\n\\tcount = a[0] * a[1] / 2\\nelse:\\n\\tcount = (a[0] * a[1] - 1) / 2\\nprint(int(count))\\n\",\n \"(m, n) = input().split(' ')\\n(m, n) = (int(m), int(n))\\nif m % 2 == 1 and n % 2 == 0 or (m % 2 == 0 and n % 2 == 1):\\n\\toutput = int(m * n / 2)\\nelse:\\n\\toutput = int((m * n - 1) / 2) if int(m * n / 2) % 2 else int(m * n / 2)\\nprint(output)\\n\",\n \"import math\\nline = input()\\nn = int(line.split(' ')[0])\\nm = int(line.split(' ')[1])\\ncount = 0\\nif n % 2 == 0:\\n\\tcount += math.floor(n / 2) * m\\nelse:\\n\\tcount += math.floor(n / 2) * m\\n\\tcount += math.floor(m / 2)\\nprint(count)\\n\",\n \"(n, m) = list(map(int, input().split()))\\na = 2 * 1\\ns = m * n // a\\nprint(s)\\n\",\n \"(n, m) = map(int, input().split())\\ns = 0\\nx2 = n // 2\\ny2 = m // 2\\ns += x2 * y2 * 2\\nif n - x2 * 2 == 1:\\n\\ts += y2\\nif m - y2 * 2 == 1:\\n\\ts += x2\\nprint(s)\\n\",\n \"(n, m) = map(int, input().split())\\nif n * m % 2 == 0 or n * m % 2 != 0:\\n\\tprint(n * m // 2)\\n\",\n \"board_sizes = input().split()\\nboard_size_as_int = list(map(lambda inp: int(inp), board_sizes))\\n(m, n) = board_size_as_int\\nif m * n > 1:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(0)\\n\",\n \"inp = input()\\ns = inp.find(' ')\\nw = int(inp[:s])\\nh = int(inp[s:])\\nh *= w\\nh /= 2\\nh = int(h)\\nprint(h)\\n\",\n \"(m, n) = map(int, input().split())\\no = m * n\\nx = o // 2\\nprint(x)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif N % 2 == 0:\\n\\tk = M * (N // 2)\\nelse:\\n\\tk = M * (N // 2) + M // 2\\nprint(k)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nimport math\\nval = m / 2 * (n / 1)\\nval1 = m / 1 * (n / 2)\\nprint(int(max(val, val1)))\\n\",\n \"dim = input()\\nd = dim.split()\\nsize = int(d[0]) * int(d[1]) / 2\\nprint(int(size))\\n\",\n \"INPTD = str(input())\\nLST = INPTD.split(' ')\\nM = int(LST[0])\\nN = int(LST[1])\\nT = 0\\n\\ndef count_dominos_row(row_length, is_big_row):\\n\\tif is_big_row:\\n\\t\\treturn row_length\\n\\telse:\\n\\t\\treturn row_length // 2\\nwhile True:\\n\\tif N == 1:\\n\\t\\tT += count_dominos_row(M, False)\\n\\telse:\\n\\t\\tT += count_dominos_row(M, True)\\n\\tN = N - 2\\n\\tif N <= 0:\\n\\t\\tbreak\\nprint(T)\\n\",\n \"import math\\n(w, l) = map(int, input().split())\\nout = w * l / 2\\nprint(int(out))\\n\",\n \"import math as Math\\n(M, N) = map(int, input().split())\\nprint(Math.floor(M * N * 0.5))\\n\",\n \"listt = input().split()\\nM = int(listt[0])\\nN = int(listt[1])\\nanswer = str(M * N // 2)\\nprint(answer)\\n\",\n \"dim = input().split(' ')\\nm = int(dim[0])\\nn = int(dim[1])\\nif not m % 2:\\n\\tprint(int(m / 2 * n))\\nelif not n % 2:\\n\\tprint(int(n / 2 * m))\\nelse:\\n\\tprint(int(m // 2 * n + n // 2))\\n\",\n \"(N, M) = map(int, input().split())\\nimport math\\nz = math.floor(N * M / 2)\\nprint(z)\\n\",\n \"input_ = input()\\ninput_list = input_.split(' ')\\nM = int(input_list[0])\\nN = int(input_list[1])\\nsurface = M * N\\nprint(surface // 2)\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef insr():\\n\\ts = input()\\n\\treturn list(s[:len(s) - 1])\\n\\ndef invr():\\n\\treturn map(int, input().split())\\n(m, n) = invr()\\nif m % 2 == 1 and n % 2 == 1:\\n\\tprint((m * n - 1) // 2)\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"s = str(input())\\nlst = s.split(' ')\\nk = 0\\nif int(lst[1]) % 2 == 0:\\n\\tk = int(lst[1]) / 2 * int(lst[0])\\n\\tprint(int(k))\\nelse:\\n\\tk = (int(lst[1]) - 1) / 2 * int(lst[0]) + int(lst[0]) / 2\\n\\tprint(int(k))\\n\",\n \"a = [int(s) for s in input().split()]\\nm = a[0]\\nn = a[1]\\nk = m * n // 2\\nprint(k)\\n\",\n \"(m, n) = map(int, input().split())\\n(width, heigth) = (0, 0)\\nif m > n:\\n\\twidth = m\\n\\theigth = n\\nelse:\\n\\twidth = n\\n\\theigth = m\\nrem = 0 if width % 2 == 0 else int(heigth / 2)\\nprint(int(width / 2) * heigth + rem)\\n\",\n \"from math import floor\\nvals = list(map(int, input().split()))\\nprint(floor(vals[0] * vals[1] / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nm = int(m)\\nn = int(n)\\nv = m // 2 * n\\nh = m % 2 * (n // 2)\\nprint(v + h)\\n\",\n \"from math import floor\\n(M, N) = [int(i) for i in input().split()]\\nprint(floor(M * N / 2))\\n\",\n \"e = input().split()\\na = int(e[0])\\nb = int(e[1])\\ns = a * b\\nprint(int(s / 2))\\n\",\n \"(a, b) = map(int, input().split())\\nt = a * b // 2\\nprint(t)\\n\",\n \"import sys\\nuserInput = sys.stdin.readlines()\\na = list(map(int, userInput[0][:-1].split(' ')))\\n(m, n) = (a[0], a[1])\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nif m == 1 and n == 1:\\n\\tresult = 0\\nelse:\\n\\tN = n // 2\\n\\tN_ = n % 2\\n\\tM = m // 2\\n\\tM_ = m % 2\\n\\tif N_ == 0:\\n\\t\\tresult = m * N\\n\\telse:\\n\\t\\tresult = m * N + M\\nprint(result)\\n\",\n \"def fnc(m, n):\\n\\tif m % 2 == 0:\\n\\t\\treturn n * int(m / 2)\\n\\telse:\\n\\t\\treturn n * int(m / 2) + int(n / 2)\\nt = list(map(int, input().strip().split()))\\nprint(fnc(t[0], t[1]))\\n\",\n \"string = input()\\nM = string.split(' ')\\npro = int(M[0]) * int(M[1])\\nprint(int(pro / 2))\\n\",\n \"from math import floor\\nraw_data = input().split()\\nlength = int(raw_data[0])\\nheight = int(raw_data[1])\\ndlength = 2\\ndheight = 1\\nvert_spacing = length / dlength\\nif vert_spacing % 2 != 0:\\n\\tvert_spacing = floor(vert_spacing)\\nhoriz_spacing = height / dheight\\nif horiz_spacing % 2 != 0:\\n\\thoriz_spacing = floor(horiz_spacing)\\nthird_spacing = 0\\nif length - vert_spacing * dlength == 1:\\n\\tthird_spacing = height / dlength\\n\\tif third_spacing % 2 != 0:\\n\\t\\tthird_spacing = floor(third_spacing)\\nnumber_of_dominos = horiz_spacing * vert_spacing + third_spacing\\nnumber_of_dominos = int(number_of_dominos)\\nprint(number_of_dominos)\\n\",\n \"while True:\\n\\t(M, N) = map(int, input().split(' '))\\n\\tif M >= 1 and M <= N and (N <= 16):\\n\\t\\tbreak\\nif N % 2 == 0:\\n\\tprint(int(N / 2) * M)\\nelse:\\n\\tprint(int(N / 2) * M + int(M / 2))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\ndom = int(m * n / 2)\\nprint(dom)\\n\",\n \"def solve(t):\\n\\treturn t['m'] * t['n'] // 2\\ntc = {}\\n(tc['m'], tc['n']) = [int(s) for s in input().split(' ')]\\nprint('{}'.format(solve(tc)))\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nd = a // m * a // n\\nprint(d // 2)\\n\",\n \"(M, N) = map(int, input().split(' '))\\nif N % 2 == 1:\\n\\tans = int(M / 2)\\n\\tans += M * int((N - 1) / 2)\\nelse:\\n\\tans = M * int(N / 2)\\nprint(ans)\\n\",\n \"def main():\\n\\tnm = [int(number) for number in input().split(' ')]\\n\\tprint(nm[0] * nm[1] // 2)\\nmain()\\n\",\n \"(m, n) = map(int, input().split())\\nx = 0\\ny = 0\\nz = 0\\nif m == 1 and n == 1:\\n\\tprint('0')\\nif m == 1 and n >= 2 or (n == 1 and m >= 2):\\n\\tif m > n:\\n\\t\\tprint(m // 2)\\n\\telse:\\n\\t\\tprint(n // 2)\\nelif m >= 2 and n >= 2:\\n\\tx = m // 2\\n\\ty = n\\n\\tz = x * y\\n\\tif m % 2 != 0:\\n\\t\\tz = z + n // 2\\n\\tprint(z)\\n\",\n \"(m, n) = map(int, input().split())\\ndomino = 0\\nif m < 2 and n < 2:\\n\\tdomino = domino\\nelif m % 2 == 0 or n % 2 == 0:\\n\\tdomino = n * m // 2\\nelse:\\n\\tdomino = n * m // 2\\nprint(domino)\\n\",\n \"s = input().split()\\na = int(s[0])\\nb = int(s[1])\\ntemp = a * b\\nans = temp // 2\\nprint(ans)\\n\",\n \"import math\\n(n, m) = map(int, input().strip().split())\\nif n * m == 1:\\n\\tprint('0')\\nelse:\\n\\tif n % 2 == 0 or m % 2 == 0:\\n\\t\\tmax_dom = n * m / 2\\n\\telse:\\n\\t\\tmax_dom = n * m / 2 - 1 / 2\\n\\tprint(int(max_dom))\\n\",\n \"board = input().split(' ')\\nnumberOfDominos = int(board[0]) * int(board[1]) // 2\\nprint(numberOfDominos)\\n\",\n \"t = 0\\nwhile t == 0:\\n\\t(a, b) = map(int, input().split(' '))\\n\\tif 1 <= a <= b <= 16:\\n\\t\\tsuma = 0\\n\\t\\tr = a % 2\\n\\t\\tt = a // 2\\n\\t\\tt = t * b\\n\\t\\tsuma += t\\n\\t\\tif r == 1:\\n\\t\\t\\tsuma += b // 2\\n\\t\\tprint(suma)\\n\\t\\tt = 1\\n\\telse:\\n\\t\\tt = 0\\n\",\n \"(N, M) = input().split(' ')\\nn = int(N)\\nm = int(M)\\nres = int(n * m / 2)\\nprint(res)\\n\",\n \"angka = input().split()\\nM = int(angka[0])\\nN = int(angka[1])\\nkali = M * N\\nhasil = kali // 2\\nprint(hasil)\\n\",\n \"(m, n) = map(int, input().strip().split())\\ncount = m // 2 * n\\nif m % 2 != 0:\\n\\tcount += n // 2\\nprint(count)\\n\",\n \"(m, n) = tuple(map(int, input().split(' ')))\\nans = m * n // 2\\nprint(ans)\\n\",\n \"import math\\n(a, b) = input().split(' ')\\narea = int(a) * int(b)\\nprint(math.trunc(area / 2))\\n\",\n \"(m, n) = [int(val) for val in input().split()]\\nprint(int(m * n / 2))\\n\",\n \"[m, n] = [int(_) for _ in input().split()]\\nprint(m * n >> 1)\\n\",\n \"(m, n) = map(int, input().split())\\nmn = m * n\\nnoDom = int(mn / 2)\\nprint(noDom)\\n\",\n \"dim = input()\\n(m, n) = dim.split()\\nm = int(m)\\nn = int(n)\\nbig = m * n\\nans = int(big // 2)\\nprint(ans)\\n\",\n \"mnStr = input()\\nmnLs = mnStr.split()\\nm = int(mnLs[0])\\nn = int(mnLs[1])\\nans = m * n // 2\\nprint(ans)\\n\",\n \"l = list(map(int, input().split()))\\ns = l[0] * l[1]\\nprint(s // 2)\\n\",\n \"from functools import reduce\\ntotal = reduce(lambda x, y: x * y, [int(x) for x in input().split(' ')])\\nprint((total - total % 2) // 2)\\n\",\n \"(w, n) = list(map(int, input().split(' ')))\\nprint(w * n // 2)\\n\",\n \"inp = input().split()\\na = int(inp[0]) * int(inp[1])\\na = a // 2\\nprint(a)\\n\",\n \"(m, n) = tuple(map(int, input().split()))\\n(a, b) = (m // 2, n // 2)\\nprint(a * b * 2 + (m * n - 4 * a * b) // 2)\\n\",\n \"a = input().split()\\nq = int(a[0])\\nw = int(a[1])\\nr = q * w / 2\\nc = int(r)\\nprint(c)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0:\\n\\tl1 = int(m / 2)\\n\\tt = l1 * n\\nelif n % 2 == 0:\\n\\tl1 = int(n / 2)\\n\\tt = l1 * m\\nelse:\\n\\tl1 = int(m / 2) * n\\n\\tl2 = int(n / 2)\\n\\tt = l1 + l2\\nprint(t)\\n\",\n \"rect = list(map(int, input().split()))\\nx = rect[0] * rect[1]\\ny = 2\\nz = x // y\\nprint(z)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\np = m * n\\nif p % 2 == 0:\\n\\tprint(int(p / 2))\\nelse:\\n\\tk = p - 1\\n\\tprint(int(k / 2))\\n\",\n \"wt = input().split()\\nprint(int(wt[0]) * int(wt[1]) // 2)\\n\",\n \"list = input().split()\\nk = 1\\nfor i in list:\\n\\tk *= int(i)\\nprint(k // 2)\\n\",\n \"from sys import stdin, stdout\\n(m, n) = (int(x) for x in stdin.readline().split())\\nprint(m * n // 2)\\n\",\n \"mn = input()\\nMN = mn.split(' ')\\nM = int(MN[0])\\nN = int(MN[1])\\nmaximun = int()\\nif M % 2 == 1:\\n\\tm = M // 2\\n\\tn = N // 2\\n\\tmaximun = int(m * N + n)\\nelse:\\n\\tmaximun = int(M / 2 * N)\\nprint(maximun)\\n\",\n \"def main():\\n\\t(x, y) = map(int, input().split())\\n\\tprint(int(x * y / 2))\\nmain()\\n\",\n \"(n, m) = [int(i) for i in input().split()]\\nhorizontal = n // 2\\nh_rem = n % 2\\nvertical = 0\\nif h_rem > 0:\\n\\tvertical = m // 2\\nprint(horizontal * m + vertical)\\n\",\n \"d = input().split(' ')\\nn = int(d[0])\\nm = int(d[1])\\nprint(m * (n // 2) + n % 2 * (m // 2))\\n\",\n \"(n, m) = map(int, input().split())\\nif m > n:\\n\\tx = n\\n\\tn = m\\n\\tm = x\\nc = m // 2 * n + m % 2 * (n // 2)\\nprint(c)\\n\",\n \"(m, n) = map(int, input().split())\\ncount = 0\\nfor i in range(1, n * m):\\n\\tif i * 2 <= n * m:\\n\\t\\tcount = count + 1\\n\\telse:\\n\\t\\tbreak\\nprint(count)\\n\",\n \"(m, n) = map(int, input().split())\\nif m >= n:\\n\\t(m, n) = (n, m)\\na = int(m // 2)\\nb = m - 2 * a\\nc = int(n // 2)\\ns = a * n + b * c\\nprint(s)\\n\",\n \"(M, N) = map(int, input().split())\\noutput = M * N // 2\\nprint(output)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nb = M * N\\nif b % 2 == 0:\\n\\ts = b / 2\\nelse:\\n\\ts = (b - 1) / 2\\ns = int(s)\\nprint(s)\\n\",\n \"def main():\\n\\tip = input()\\n\\t(M, N) = [int(i) for i in ip.split()]\\n\\tprint(M * N // 2)\\nmain()\\n\",\n \"inp = input().split(' ')\\nn = int(inp[0])\\nm = int(inp[1])\\ndom = 0\\nif int(n) % 2 == 0 or int(m) % 2 == 0:\\n\\tdom = m * n / 2\\nelse:\\n\\tdom = (n - 1) / 2 * m + (m - 1) / 2\\nprint(int(dom))\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nAr = a * b\\nA = Ar / 2\\nprint(int(A))\\n\",\n \"import math\\n(m1, n1) = map(int, input().split())\\nm = max(m1, n1)\\nn = min(m1, n1)\\nk = math.floor(n / 2) * m\\nif n % 2:\\n\\tk += math.floor(m / 2)\\nprint(k)\\n\",\n \"def main():\\n\\t(m, n) = [int(x) for x in input().split()]\\n\\tif m <= 1 and n <= 1:\\n\\t\\tprint(0)\\n\\telse:\\n\\t\\tmax_dominos = {(1, 1): 0}\\n\\t\\t(i, j) = (1, 1)\\n\\t\\twhile i < m or j < n:\\n\\t\\t\\tif i < m:\\n\\t\\t\\t\\ti += 1\\n\\t\\t\\t\\tarea = i * j\\n\\t\\t\\t\\tcovered_area = max_dominos[i - 1, j] * 2\\n\\t\\t\\t\\tuncovered = area - covered_area\\n\\t\\t\\t\\tmax_dominos[i, j] = max_dominos[i - 1, j] + uncovered // 2\\n\\t\\t\\tif j < n:\\n\\t\\t\\t\\tj += 1\\n\\t\\t\\t\\tarea = i * j\\n\\t\\t\\t\\tcovered_area = max_dominos[i, j - 1] * 2\\n\\t\\t\\t\\tuncovered = area - covered_area\\n\\t\\t\\t\\tmax_dominos[i, j] = max_dominos[i, j - 1] + uncovered // 2\\n\\t\\tprint(max_dominos[m, n])\\nmain()\\n\",\n \"(n, m) = list(map(int, input().split()))\\nans = n // 2 * m\\nif n > 0 and n % 2 != 0:\\n\\tans = ans + m // 2\\nprint(ans)\\n\",\n \"from math import ceil\\nfrom math import floor\\n\\ndef mod_expo(n, p, m):\\n\\tresult = 1\\n\\twhile p != 0:\\n\\t\\tif p % 2 == 1:\\n\\t\\t\\tresult = result * n % m\\n\\t\\tp //= 2\\n\\t\\tn = n * n % m\\n\\treturn result\\n\\ndef find_least_diff(n):\\n\\tA = 2 * (pow(2, n / 2 - 1) - 1)\\n\\tB = -pow(2, n / 2)\\n\\treturn int(abs(B - A))\\n\\ndef find_ways(n):\\n\\treturn (n - 1) // 2\\n\\ndef count_possibilities(n, m):\\n\\tA = mod_expo(2, m, pow(10, 9) + 7)\\n\\treturn mod_expo(A - 1, n, pow(10, 9) + 7)\\n\\ndef min_string(n, k, text):\\n\\ttext = sorted(text)\\n\\tif text[0] == text[k - 1]:\\n\\t\\tprint(''.join((text[i] for i in range(k - 1, n))))\\n\\telse:\\n\\t\\tprint(text[k - 1])\\n\\ndef get_board(n, m, mat):\\n\\tfor i in range(n):\\n\\t\\tfor j in range(m):\\n\\t\\t\\tprint(i, j)\\n\\t\\t\\tif mat[i][j] == '.':\\n\\t\\t\\t\\tif (j > 0 and mat[i][j - 1] != 'B') and (i > 0 and mat[i - 1][j] != 'B'):\\n\\t\\t\\t\\t\\tmat[i][j] = 'B'\\n\\t\\t\\t\\telse:\\n\\t\\t\\t\\t\\tmat[i][j] = 'W'\\n\\tfor i in range(n):\\n\\t\\tfor j in range(m):\\n\\t\\t\\tprint(mat[i][j])\\nt = 1\\nwhile t:\\n\\tt = t - 1\\n\\tcount = 0\\n\\tpx = []\\n\\tpy = []\\n\\t(n, m) = map(int, input().split())\\n\\tprint(floor(n * m / 2))\\n\",\n \"dom = [int(x) for x in input().split()]\\nprint(dom[0] * dom[1] // 2)\\n\",\n \"l = lambda : map(int, input().split())\\n(m, n) = l()\\nprint(m * n // 2)\\n\",\n \"def solve(m, n):\\n\\tprint(m * n // 2)\\nfor _ in range(1):\\n\\t(m, n) = map(int, input().split())\\n\\tsolve(m, n)\\n\",\n \"def main():\\n\\t(M, N) = input('').split()\\n\\t(M, N) = (int(M), int(N))\\n\\tarea = M * N\\n\\tdomino_count = int(area / 2)\\n\\tprint(domino_count)\\nmain()\\n\",\n \"inp = input()\\nl = inp.split()\\ntotal = int(l[0]) * int(l[1])\\nnum = total // 2\\nprint(num)\\n\",\n \"(M, N) = map(int, input().split())\\ns = M * N\\nn = s // 2\\nprint(n)\\n\",\n \"def main1():\\n\\tn = list(map(int, input().rstrip().split()))\\n\\tprint(n[0] * n[1] // 2)\\nmain1()\\n\",\n \"(m, n) = map(int, input().split())\\n\\ndef is_even(x):\\n\\treturn x % 2 == 0\\nif is_even(m) or is_even(n):\\n\\tprint(m * n // 2)\\nelse:\\n\\tprint((m * n - 1) // 2)\\n\",\n \"nm = [int(i) for i in input().split(' ')]\\nprint(nm[0] * nm[1] // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nS = M * N\\nif S % 2 == 0:\\n\\tb = S // 2\\n\\tprint(b)\\nelse:\\n\\tb = S // 2\\n\\tprint(b)\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\ntotArea = n * m\\nprint(int(totArea / 2))\\n\",\n \"try:\\n\\t(N, M) = map(int, input().split())\\n\\tprint(N * M // 2)\\nexcept EOFError:\\n\\tpass\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\narea = m * n\\nmx = area // 2\\nprint(mx)\\n\",\n \"domino = input().split(' ')\\na = int(domino[0])\\nb = int(domino[1])\\nx = int(a * b / 2)\\nprint(x)\\n\",\n \"mnStr = input()\\n(m, n) = [int(ch) for ch in mnStr.split()]\\nmatrixCells = m * n\\nif matrixCells % 2 == 0:\\n\\tprint(int(matrixCells / 2))\\nelse:\\n\\tprint(int((matrixCells - 1) / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\n\\ndef domino(m, n):\\n\\tx = m * n\\n\\treturn math.floor(x / 2)\\nprint(domino(m, n))\\n\",\n \"brett = input().split()\\na = int(brett[0]) * int(brett[1])\\nanzahl = int(a / 2)\\nprint(anzahl)\\n\",\n \"i = lambda : map(int, input().split())\\n(n, k) = i()\\nfinal = int(n * k // 2)\\nprint(final)\\n\",\n \"from math import floor\\n\\ndef domino_spill(m, n):\\n\\tif m * n == 1:\\n\\t\\treturn 0\\n\\tif n == 1:\\n\\t\\treturn floor(m / 2)\\n\\tif n == 0:\\n\\t\\treturn 0\\n\\tif m % 2 == 0:\\n\\t\\treturn m // 2 + domino_spill(m, n - 1)\\n\\telse:\\n\\t\\treturn m + domino_spill(m, n - 2)\\ninp = input()\\n(m, n) = [int(i) for i in inp.split(' ')]\\nprint(domino_spill(m, n))\\n\",\n \"(x, y) = input().split()\\nc = int(x) * int(y)\\na = 0\\ncnt = -1\\nwhile a <= c:\\n\\ta = a + 2\\n\\tcnt = cnt + 1\\nprint(cnt)\\n\",\n \"dimensions = str(input()) + ' '\\ndimensionslist = []\\nword = ''\\nfor char in dimensions:\\n\\tif char != ' ':\\n\\t\\tword += char\\n\\telse:\\n\\t\\tdimensionslist.append(int(word))\\n\\t\\tword = ''\\nm = dimensionslist[0]\\nn = dimensionslist[1]\\nif m * n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"line = input()\\n(a, b) = (int(line.split(' ')[0]), int(line.split(' ')[1]))\\nresult = 0\\nresult += a / 1 * int(b / 2)\\nresult += int(a / 2) * int(b % 2)\\nprint(int(result))\\n\",\n \"nums = [int(x) for x in input().split()]\\nM = nums[0]\\nN = nums[1]\\nboard_area = M * N\\ndom_area = 2\\nprint(board_area // dom_area)\\n\",\n \"CiagZKlawiatury = input().split(' ')\\nN = int(CiagZKlawiatury[0])\\nM = int(CiagZKlawiatury[1])\\nWynik = N * M // 2\\nprint(Wynik)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nb = m * n\\nprint(b // 2)\\n\",\n \"side = list(map(int, input().split()))\\narea = side[0] * side[1]\\ndomino = area // 2\\nprint(domino)\\n\",\n \"strink = str(input())\\n(m, n) = strink.split()\\nm = int(m)\\nn = int(n)\\ncount = 0\\nif m % 2 == 0:\\n\\tcount = count + m // 2 * n\\nelif n % 2 == 0:\\n\\tcount = count + n // 2 * m\\nelse:\\n\\tcount = count + m // 2 * n + n // 2\\nprint(count)\\n\",\n \"(n, a) = input().split()\\nsq_inp = int(n) * int(a)\\nprint(sq_inp // 2)\\n\",\n \"a = list(map(int, input().split(' ')))\\nlength = a[0]\\nbreadth = a[1]\\nno_of_dominoes = int(length * breadth / 2)\\nprint(no_of_dominoes)\\n\",\n \"(n, m) = map(int, input().split())\\ns = n * m\\ns1 = 2 * 1\\nk = s // s1\\nprint(k)\\n\",\n \"(M, N) = map(int, input().strip().split())\\nif not M * N % 2 == 0:\\n\\tprint(int((M * N - 1) / 2))\\nelse:\\n\\tprint(int(M * N / 2))\\n\",\n \"square = input()\\nsquare = square.split(' ')\\nM = int(square[0])\\nN = int(square[1])\\ndominos = M * N // 2\\nprint(dominos)\\n\",\n \"(r, c) = [int(x) for x in input().split()]\\nrO = r % 2 == 1\\ncO = c % 2 == 1\\nrr = r - 1 if rO else r\\ncc = c - 1 if cO else c\\nprint(str(rr * cc // 2 + (rr // 2 if cO else 0) + (cc // 2 if rO else 0)))\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\narea = m * n\\ndomino = math.floor(area / 2)\\nprint(domino)\\n\",\n \"import math\\n(n, m) = input().split()\\n(n, m) = [int(n), int(m)]\\nsa = n * m\\nprint(math.floor(sa / 2))\\n\",\n \"board = input()\\nboard = board.split(' ')\\nm = board[0]\\nn = board[1]\\nm = m.replace(' ', '')\\nn = n.replace(' ', '')\\ntile = int(m) * int(n)\\ndom = tile // 2\\nprint(dom)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nif m * n == 1:\\n\\tprint(0)\\nelse:\\n\\ta = max(m, n)\\n\\tx = a // 2\\n\\tr = a % 2\\n\\tprint(x * (m + n - a) + r * ((m + n - a) // 2))\\n\",\n \"class Solution:\\n\\n\\tdef __init__(self, m: int, n: int) -> None:\\n\\t\\tself.m = m\\n\\t\\tself.n = n\\n\\n\\tdef pileUp(self):\\n\\t\\treturn self.m * self.n // 2\\n\\ndef main():\\n\\t(m, n) = map(int, input().strip().split())\\n\\tsolution = Solution(m, n)\\n\\tprint(solution.pileUp())\\nmain()\\n\",\n \"def dominos(m, n):\\n\\tx = 0\\n\\tif m % 2 == 0:\\n\\t\\tx = m // 2 * n\\n\\telse:\\n\\t\\tx = m // 2 * n + n // 2\\n\\treturn x\\n(m, n) = map(int, input().split())\\nprint(dominos(m, n))\\n\",\n \"import math\\n(x, y) = map(int, input().split(' '))\\na = x * y\\nans = math.floor(a / 2)\\nprint(ans)\\n\",\n \"input_list = []\\nnum = 0\\nwhile True:\\n\\tif num == 1:\\n\\t\\tbreak\\n\\tline = input().split()\\n\\tline = list(map(int, line))\\n\\tinput_list.append(line)\\n\\tnum += 1\\nprint(input_list[0][0] * input_list[0][1] // 2)\\n\",\n \"l = list(map(int, input().split()))\\nM = l[0]\\nN = l[1]\\na = M * N\\nif M <= 16 and N <= 116 and (M >= 1) and (N >= 1):\\n\\tif M % 2 == 0 or N % 2 == 0:\\n\\t\\tx = a / 2\\n\\tif M % 2 != 0 or N != 0:\\n\\t\\tx = a // 2\\nprint(x)\\n\",\n \"import math\\n(a, b) = [int(i) for i in str.split(input())]\\ns = a * b\\nprint(math.floor(s / 2))\\n\",\n \"t = input()\\nl = list(map(int, t.split(' ')))\\nn = l[0] * l[1]\\nif n % 2 == 0:\\n\\tprint(int(n / 2))\\nelse:\\n\\tprint(int((n - 1) / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nd = 2\\n\\ndef domino():\\n\\tprint(n * m // 2)\\ndomino()\\n\",\n \"(m, n) = map(int, input().strip().split(' '))\\ndomino_size = 2\\nprint(int(m * n / domino_size))\\n\",\n \"import math\\n(x, n) = map(int, input().split())\\nprint(math.floor(x * n / 2))\\n\",\n \"(m, n) = map(int, input().split())\\ncount = 0\\nif m % 2 != 0 and n != 0:\\n\\tprint(m * n // 2)\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"def main():\\n\\t(m, n) = list(map(int, input().split()))\\n\\tprint(m * n // (2 * 1))\\nmain()\\n\",\n \"(m, n) = tuple(map(int, input().split(' ')))\\nt = m * n\\ni = 0\\nwhile t > 1:\\n\\tt -= 2\\n\\ti += 1\\nprint(i)\\n\",\n \"a = [int(i) for i in input().split()]\\nt = (a[0] * a[1] - 0.4) / 2\\nprint('{:.0f}'.format(t))\\n\",\n \"k = input()\\nk = k.split()\\nfor x in range(2):\\n\\tk[x] = int(k[x])\\nprint(int(k[1] * k[0] / 2))\\n\",\n \"(a, b) = input().split(' ')\\n(a, b) = (int(a), int(b))\\nprint(str(a * b // 2))\\n\",\n \"[n, m] = [int(a) for a in input().split(' ')]\\ndominos = n * m // 2\\nprint(dominos)\\n\",\n \"while True:\\n\\ta = list(map(int, input().split()))\\n\\tif a[1] % 2 == 0:\\n\\t\\tp = a[1] // 2 * a[0]\\n\\telse:\\n\\t\\tp = a[1] // 2 * a[0] + a[0] // 2\\n\\tbreak\\nprint(p)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nminval = min(m, n)\\nmaxval = max(m, n)\\nd = minval // 2\\nr = minval % 2\\ns = maxval // 2\\nsquares = maxval * d + r * s\\nprint(squares)\\n\",\n \"size = input('').split()\\nsize = int(size[0]) * int(size[1])\\nfor i in range(0, size + 1, 2):\\n\\tpass\\nprint(i // 2)\\n\",\n \"(m, n) = input().split(' ')\\nc = 0\\nx = int(m) * int(n)\\nwhile x > 1:\\n\\tx -= 2\\n\\tc += 1\\nprint(c)\\n\",\n \"str1 = input()\\nstr1 = list(str1.split(' '))\\nn = int(str1[0])\\nm = int(str1[1])\\nk = m * n\\nprint(k // 2)\\n\",\n \"import math\\na = input().split()\\nprint(math.floor(int(a[0]) * int(a[1]) / 2))\\n\",\n \"crap = input().split()\\nprint(int(crap[0]) * int(crap[1]) // 2)\\n\",\n \"from functools import reduce\\nimport os\\nimport sys\\nfrom math import *\\nfrom collections import *\\nfrom fractions import *\\nfrom bisect import *\\nfrom heapq import *\\nfrom io import BytesIO, IOBase\\ninput = lambda : sys.stdin.readline().rstrip('\\\\r\\\\n')\\n\\ndef value():\\n\\treturn tuple(map(int, input().split()))\\n\\ndef arr():\\n\\treturn [int(i) for i in input().split()]\\n\\ndef sarr():\\n\\treturn [int(i) for i in input()]\\n\\ndef inn():\\n\\treturn int(input())\\nmo = 1000000007\\n(m, n) = value()\\nprint(m * n // 2)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nd = area // 2\\nprint(d)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0:\\n\\tanswer = n * (m / 2)\\n\\tprint(int(answer))\\nelif m % 2 != 0 and n % 2 == 0:\\n\\tanswer = m * (n / 2)\\n\\tprint(int(answer))\\nelif m % 2 != 0 and n % 2 != 0:\\n\\tanswer = max(m * (n / 2), n * (m / 2))\\n\\tprint(int(answer))\\n\",\n \"arr = [int(i) for i in input().split(' ')]\\nprint(arr[0] * arr[1] // 2)\\n\",\n \"import math\\nip = input()\\n(m, n) = (int(ip.split(' ')[0]), int(ip.split(' ')[1]))\\nif m > n or n > 16 or m < 1:\\n\\tprint('')\\nres = math.floor(m * n / 2)\\nprint(res)\\n\",\n \"import sys\\n(M, N) = list(map(int, sys.stdin.read().split()))\\nboth_even = M % 2 == 0 or N % 2 == 0\\nif both_even:\\n\\tprint(int(M * N / 2))\\nelse:\\n\\tprint(int((M * N - 1) / 2))\\n\",\n \"(r, s) = list(map(int, input().split()))\\nt = 2 * 1\\nba = r * s\\nprint(ba // t)\\n\",\n \"(l, b) = map(int, input().split())\\nfill = int(l * b / 2)\\nprint(fill)\\n\",\n \"k = input()\\nl = list(k.split())\\ni = 0\\nwhile i < len(l):\\n\\tl[i] = int(l[i])\\n\\ti += 1\\nm = l[0]\\nn = l[1]\\ns = m * n\\nprint(int(s / 2))\\n\",\n \"import math\\n(N, M) = map(int, input().split())\\nif M * N == 1:\\n\\tprint(0)\\n\\texit()\\nif M * N % 2 == 0:\\n\\tprint(int(M * N / 2))\\nelse:\\n\\tprint(math.ceil(M * N / 2) - 1)\\n\",\n \"string = input()\\nnumbers = string.split()\\nm = int(numbers[0])\\nn = int(numbers[1])\\nx = m * n // 2\\nprint(x)\\n\",\n \"m = ''\\nn = ''\\nfor (m, n) in (str(input()).split(),):\\n\\tresult = int(m) * int(n) // 2\\n\\tprint(result)\\n\",\n \"import math\\ninp = input()\\ninp.split(' ')\\nn = int(inp[0:2])\\nm = int(inp[2:5])\\nfinal = n * m\\nfinal1 = final / 2\\nprint(math.floor(final1))\\n\",\n \"(M, N) = list(map(int, input().split()))\\nresult = M * N\\nwhile result % 2 != 0:\\n\\tresult -= 1\\nelse:\\n\\tprint(result // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\narea = m * n\\nd = 2\\nif area % d == 0:\\n\\tprint(int(area / d))\\nelif area % d != 0:\\n\\tprint(int(area / d))\\n\",\n \"(m, n) = map(int, input().split())\\nl = 0\\nwhile n != 0:\\n\\tif n > 1:\\n\\t\\tl += m\\n\\t\\tn = n - 2\\n\\telse:\\n\\t\\tl += m // 2\\n\\t\\tn = n - 1\\nprint(l)\\n\",\n \"(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nz = x * y\\ndominoes = z // 2\\nprint(dominoes)\\n\",\n \"import math\\nA = input()\\nB = A.split(' ')\\n[m, n] = [int(i) for i in B]\\nprint(math.floor(m * n / 2))\\n\",\n \"inp = input().split()\\nx = int(inp[0])\\ny = int(inp[1])\\nanswer = x * y / 2\\nprint(int(answer))\\n\",\n \"str1 = input()\\na = int(str1.split()[0])\\nb = int(str1.split()[1])\\nprint(a * b // 2)\\n\",\n \"from math import floor\\ndominoes = 0\\nmn = str(input())\\nm = int(mn.split(' ')[0])\\nn = int(mn.split(' ')[1])\\nshorter = min(m, n)\\nif shorter > 1:\\n\\tdominoes = max(m, n) * floor(shorter / 2)\\n\\tif not (shorter / 2).is_integer():\\n\\t\\tdominoes += floor(max(m, n) / 2)\\nelse:\\n\\tdominoes = floor(max(m, n) / 2)\\nprint(dominoes)\\n\",\n \"(M, N) = map(int, input().split())\\namt = M * N // 2\\nprint(amt)\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\nif not a or not b:\\n\\tprint('0')\\nelse:\\n\\tp = a * b\\n\\tp = int(p // 2)\\n\\tprint(p)\\n\",\n \"(m, n) = map(int, input().split())\\ndomino_size = 2 * 1\\nboard_size = m * n\\ncount = board_size // domino_size\\nprint(count)\\n\",\n \"a = input()\\nm = ''\\nn = ''\\nc = 0\\nl = len(a)\\nfor i in range(0, l):\\n\\tif c == 0:\\n\\t\\tif a[i] != ' ':\\n\\t\\t\\tm = m + a[i]\\n\\t\\tif a[i] == ' ':\\n\\t\\t\\tc = 1\\n\\tif c == 1:\\n\\t\\tc = 2\\n\\t\\tcontinue\\n\\tif c == 2:\\n\\t\\tn = n + a[i]\\nm = int(m)\\nn = int(n)\\nif n % 2 == 0:\\n\\tc = n / 2 * m\\nelse:\\n\\tc = (n - 1) / 2 * m + m // 2\\nprint(int(c))\\n\",\n \"dims = input()\\n(m, n) = dims.split(' ')\\nm = int(m)\\nn = int(n)\\ndominos = m * n // 2\\nprint(dominos)\\n\",\n \"(n, m) = map(int, input().split())\\nif m * n % 2 == 0:\\n\\td = m * n // 2\\n\\tprint(d)\\nelif m * n % 2 != 0:\\n\\te = int(m * n / 2)\\n\\tprint(e)\\n\",\n \"inp = input().split()\\ns = int(inp[0]) * int(inp[1])\\nprint(s // 2)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nres = M * N // (2 * 1)\\nprint(res)\\n\",\n \"(m, n) = input().split()\\navailableSquares = int(m) * int(n)\\nDominos = 0\\nif availableSquares % 2 != 0:\\n\\tDominos = (availableSquares - 1) / 2\\nelif availableSquares % 2 == 0:\\n\\tDominos = availableSquares / 2\\nprint(int(Dominos))\\n\",\n \"a_b = input()\\na = int(a_b.split()[0])\\nb = int(a_b.split()[1])\\nprint(a * b // 2)\\n\",\n \"s = input().split(' ')\\nb = int(s[0]) * int(s[1])\\nif b % 2:\\n\\tprint(int((b - 1) / 2))\\nelse:\\n\\tprint(int(b / 2))\\n\",\n \"import math\\n(m, n) = [int(x) for x in input().split()]\\na = math.ceil(m * n)\\nb = math.ceil(a // 2 * 1)\\nprint(b)\\n\",\n \"inp = [int(i) for i in input().split()]\\nM = inp[0]\\nN = inp[1]\\nif M % 2 == 0 or N % 2 == 0:\\n\\tmx = int(M * N / 2)\\nelse:\\n\\tmx = int((M - 1) * N / 2 + (N - 1) / 2)\\nprint(mx)\\n\",\n \"__author__ = 'Bian'\\ninput = str(input()).split()\\nm = int(input[0])\\nn = int(input[1])\\nif m % 2 == 0 or n % 2 == 0:\\n\\tout = m * n / 2\\nelif m == 1 and n == 1:\\n\\tout = 0\\nelif m >= n:\\n\\tout = m // 2 * n + n // 2\\nelse:\\n\\tout = n // 2 * m + m // 2\\nprint(int(out))\\n\",\n \"numbers = [int(d) for d in input().split(' ')]\\nn = numbers[0]\\nm = numbers[1]\\nsize = n * m\\nprint((size - size % 2) // 2)\\n\",\n \"dimensions = str(input()).split()\\nboard = []\\nM = int(dimensions[0])\\nN = int(dimensions[1])\\ntotal = 0\\nif M % 2 == 0 or N % 2 == 0:\\n\\ttotal = M * N // 2\\nelse:\\n\\ttotal = (M - 1) * N // 2 + (N - 1) // 2\\nprint(total)\\n\",\n \"text = input()\\ntext = text.split()\\nt_l = []\\nfor i in text:\\n\\tt_l.append(int(i))\\nm = t_l[0]\\nn = t_l[1]\\nmul = m * n\\nprint(mul // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nl = M * N\\nw = l // 2\\nprint(w)\\n\",\n \"inps = input().split()\\n(col, row) = (int(inps[0]), int(inps[1]))\\nif col % 2 != 0:\\n\\tdoms = int(col / 2) * row + int(row / 2)\\nelse:\\n\\tdoms = int(col / 2) * row\\nprint(doms)\\n\",\n \"inp = input('')\\nlistaa = inp.split()\\ndim = int(listaa[0]) * int(listaa[1])\\nprint(dim // 2)\\n\",\n \"(n, k) = map(int, input().split())\\nboardSize = n * k\\nif boardSize % 2 == 0:\\n\\tprint('{:.0f}'.format(boardSize / 2))\\nelse:\\n\\tprint('{:.0f}'.format((boardSize - boardSize % 2) / 2))\\n\",\n \"import sys\\nnumbers = [int(i) for i in sys.stdin.readline().split()]\\nm = numbers[0]\\nn = numbers[1]\\nprint(int(m * n / 2))\\n\",\n \"a = list(map(int, input().split()))\\nproduct = 1\\nfor i in range(len(a)):\\n\\tproduct *= a[i]\\nans = product // 2\\nprint(ans)\\n\",\n \"s = input().split()\\na = int(s[0])\\nb = int(s[1])\\nprint(int(a * b * 0.5))\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nfitting = area // 2\\nprint(fitting)\\n\",\n \"from math import *\\n(m, n) = [int(i) for i in input().split()]\\ndominos = m * n // (2 * 1)\\nprint(dominos)\\n\",\n \"(x, y) = map(int, input().split())\\np = x * y\\nmax_num = p // 2\\nprint(max_num)\\n\",\n \"lst = input().split(' ')\\ns = int(lst[0]) * int(lst[1])\\nif s % 2:\\n\\tprint((s - 1) // 2)\\nelse:\\n\\tprint(s // 2)\\n\",\n \"x = 0\\ny = 0\\nz = 0\\n(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nif m > n:\\n\\tif m % 2 == 0:\\n\\t\\tx = m // 2\\n\\t\\ty = n\\n\\t\\tz = x * y\\n\\telif n % 2 == 0:\\n\\t\\tx = n // 2\\n\\t\\ty = m\\n\\t\\tz = x * y\\n\\telse:\\n\\t\\tx = m // 2 * n\\n\\t\\ty = n // 2\\n\\t\\tz = x + y\\nelif n > m:\\n\\tif n % 2 == 0:\\n\\t\\tx = n // 2\\n\\t\\ty = m\\n\\t\\tz = x * y\\n\\telif m % 2 == 0:\\n\\t\\tx = m // 2\\n\\t\\ty = n\\n\\t\\tz = x * y\\n\\telse:\\n\\t\\tx = n // 2 * m\\n\\t\\ty = m // 2\\n\\t\\tz = x + y\\nelif m == n:\\n\\tif n % 2 == 0:\\n\\t\\tx = n // 2\\n\\t\\ty = m\\n\\t\\tz = x * y\\n\\telse:\\n\\t\\tx = n // 2\\n\\t\\ty = m // 2\\n\\t\\tz = x * m + y\\nprint(z)\\n\",\n \"def solution(m, n):\\n\\tcount = 0\\n\\twhile True:\\n\\t\\tif m >= 2:\\n\\t\\t\\ts = m // 2\\n\\t\\t\\tm = m - s * 2\\n\\t\\t\\tcount = count + n * s\\n\\t\\tif n >= 2:\\n\\t\\t\\ts = n // 2\\n\\t\\t\\tn = n - s * 2\\n\\t\\t\\tcount = count + m * s\\n\\t\\tif n <= 1 and m <= 1:\\n\\t\\t\\tbreak\\n\\treturn count\\n\\ndef main():\\n\\t(m, n) = map(int, input().split())\\n\\tans = solution(m, n)\\n\\tprint(ans)\\nmain()\\n\",\n \"data = input()\\ndata = data.split(' ')\\ns = int(data[0]) * int(data[1])\\nresult = s // 2\\nprint(result)\\n\",\n \"dominoarea = 2\\n(linha, coluna) = input().split()\\nlinha = int(linha)\\ncoluna = int(coluna)\\narea = linha * coluna\\ndominos = area // dominoarea\\nprint(dominos)\\n\",\n \"import math as M\\n(m, n) = map(int, input().split())\\nprint(M.floor(m * n / 2))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\ns = M * N\\nif s % 2 == 0:\\n\\tnum = s // 2\\n\\tprint(num)\\nelse:\\n\\tnum = s // 2\\n\\tprint(num)\\n\",\n \"(M, N) = input().split()\\nM1 = int(M)\\nN1 = int(N)\\nX = int(M1 * N1 * 0.5)\\nprint(X)\\n\",\n \"def piling(m, n):\\n\\tGivenArea = m * n\\n\\tRequiredArea = 2 * 1\\n\\treturn GivenArea // RequiredArea\\n(m, n) = map(int, input().split(' '))\\nprint(piling(m, n))\\n\",\n \"mn = input().split(' ')\\nm = int(mn[0])\\nn = int(mn[1])\\nrows = m // 2\\nc = m % 2\\nhorizontal_dominos = 0\\nif c == 1:\\n\\thorizontal_dominos = n // 2\\nvertical_dominos = rows * n\\nprint(horizontal_dominos + vertical_dominos)\\n\",\n \"i = lambda : map(int, input().split())\\n(x, y) = i()\\nprint(x * y // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nprint(round(m * n / 2 - 0.2))\\n\",\n \"def main():\\n\\tfrom sys import stdin, stdout\\n\\t(n, m) = map(int, stdin.readline().split())\\n\\tstdout.write(str(n * m // 2))\\nmain()\\n\",\n \"numbers = input()\\n(a, b) = numbers.split(' ')\\narea = int(a) * int(b)\\nprint(area // 2)\\n\",\n \"def solve(m, n):\\n\\tdomino_pieces = 2 * 1\\n\\trectangular_board = m * n\\n\\treturn rectangular_board // domino_pieces\\n(m, n) = map(int, input().split(' '))\\nprint(solve(m, n))\\n\",\n \"dimensions = input('')\\n(m, n) = dimensions.split(' ')\\namt = int(m) * int(n) // 2\\nprint(amt)\\n\",\n \"(M, N) = input().split()\\ndomino = int(M) * int(N) // 2\\nprint(domino)\\n\",\n \"(m, n) = map(int, input().split())\\nt = 0\\nfor d in range(m * n):\\n\\tif m * n % 2 == 0:\\n\\t\\tif m * n > 2 * d:\\n\\t\\t\\tt += 1\\n\\t\\t\\tfinal = t\\n\\t\\telse:\\n\\t\\t\\tbreak\\n\\telif m * n > 2 * d:\\n\\t\\tt += 1\\n\\t\\tfinal = t - 1\\n\\telse:\\n\\t\\tbreak\\nprint(final)\\n\",\n \"(n, m) = map(int, input().split())\\nareaOfSquare = n * m\\ntotal = areaOfSquare // 2\\nprint(total)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\np = a // 2\\nprint(p)\\n\",\n \"(m, n) = list(map(int, input().split(' ')))\\n\\ndef s(a):\\n\\tif a <= 1:\\n\\t\\treturn 0\\n\\treturn a // 2 + s(a % 2)\\nprint(s(m * n))\\n\",\n \"board_size = list(map(int, input().split()))\\na = board_size[0]\\nb = board_size[1]\\ncount = 0\\nboard = [[0 for i in range(b)] for j in range(a)]\\nfor i in range(a):\\n\\tfor j in range(0, b, 2):\\n\\t\\tif b - j >= 2 and (board[i][j] == 0 and board[i][j + 1] == 0):\\n\\t\\t\\tcount += 1\\n\\t\\t\\tboard[i][j] = board[i][j + 1] = 1\\nfor j in range(b):\\n\\tfor i in range(0, a, 2):\\n\\t\\tif a - i >= 2 and (board[i][j] == 0 and board[i + 1][j] == 0):\\n\\t\\t\\tcount += 1\\n\\t\\t\\tboard[i + 1][j] = board[i][j] = 1\\nprint(count)\\n\",\n \"ip = input().split(' ')\\nm = int(ip[0])\\nn = int(ip[1])\\nprint(int(m * n / 2))\\n\",\n \"(a, b) = input('').split()\\ntotal = int(a) * int(b)\\nif total % 2 == 0:\\n\\tmax = int(total / 2)\\n\\tprint(max)\\nelse:\\n\\tmax = int((total - 1) / 2)\\n\\tprint(max)\\n\",\n \"def Domino(m, n):\\n\\treturn m * n // 2\\n(x, y) = input().split()\\nprint(Domino(int(x), int(y)))\\n\",\n \"(m, n) = list(map(int, input().split()))\\nx = m * n\\nprint(int(x / 2))\\n\",\n \"lst = list(map(int, input('\\\\n').strip().split()))[:2]\\nprint(lst[0] * lst[1] // 2)\\n\",\n \"import math\\nboard_size = input().split(' ')\\nprint(math.trunc(int(board_size[0]) * int(board_size[1]) / 2))\\n\",\n \"dim = [int(s) for s in input().split()]\\nsize = dim[0] * dim[1]\\nif size % 2 != 0:\\n\\tprint((size - 1) // 2)\\nelse:\\n\\tprint(size // 2)\\n\",\n \"arr = list(map(int, input().split(' ')))\\nn = arr[0]\\nm = arr[1]\\narea = n * m\\nprint(int(area / 2))\\n\",\n \"import math\\n(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nz = x * y\\na = math.floor(z / 2)\\nprint(a)\\n\",\n \"(n, m) = input().split(' ')\\n(n, m) = (int(n), int(m))\\nsum = n * (m // 2)\\nif m % 2 == 1:\\n\\tsum += n // 2\\nprint(sum)\\n\",\n \"b = []\\nb1 = input()\\nb2 = b1.split()\\nfor k in b2:\\n\\tb.append(int(k))\\nS = b[1] * b[0]\\nprint(S // 2)\\n\",\n \"lines = input().split()\\nlines = list(map(int, lines))\\n(x, y) = (lines[0], lines[1])\\nprint(int(x * y / 2))\\n\",\n \"(a, b) = map(int, input().split(' '))\\nif a % 2 == 1:\\n\\tc = int(a / 2)\\n\\td = b * c + int(b / 2)\\nelse:\\n\\td = int(b * a / 2)\\nprint(d)\\n\",\n \"(m, n) = list(map(int, input().strip().split()))\\narea = m * n\\ndomino = area // 2\\nprint(domino)\\n\",\n \"(M, N) = list(map(int, input().strip().split(' ')))\\nif M % 2 != 0 and N % 2 != 0:\\n\\tans = (M * N - 1) / 2\\nelse:\\n\\tans = M * N / 2\\nprint(int(ans))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m < n:\\n\\t(m, n) = (n, m)\\nx = m // 2\\ny = n // 1\\nneed = x * y\\nif m % 2 == 1 and n != 1:\\n\\tneed += n // 2\\nprint(need)\\n\",\n \"(m, n) = [int(x) for x in input().split(' ')]\\nside = m // 2\\nret = side * n\\nif side * 2 != m:\\n\\tret += n // 2\\nprint(ret)\\n\",\n \"(n, m) = [int(i) for i in input().split()]\\ny = m * n // 2\\nprint(y)\\n\",\n \"m = input()\\nls = []\\nls = m.split(' ')\\nm = int(ls[0])\\nn = int(ls[1])\\nprod = m * n\\nans = prod // 2\\nprint(ans)\\n\",\n \"def main():\\n\\t(x, y) = input().split()\\n\\tx = int(x)\\n\\ty = int(y)\\n\\tz = x * y\\n\\tz = z // 2\\n\\tprint(z)\\nmain()\\n\",\n \"def DominoPiling():\\n\\t(m, n) = map(int, input().split(' '))\\n\\tif m % 2 == 0 or n % 2 == 0:\\n\\t\\tprint(m * n // 2)\\n\\telif m == 1 or n == 1:\\n\\t\\tprint(max(m, n) // 2)\\n\\telse:\\n\\t\\tprint(min(m, n) // 2 * max(m, n) + max(m, n) // 2)\\n\\treturn None\\n\\ndef main():\\n\\tDominoPiling()\\nmain()\\n\",\n \"l = list(map(int, input().rstrip().split()))\\ntot = l[0] * l[1]\\nprint(tot // 2)\\n\",\n \"z = str(input()).split()\\ncount = int(z[0]) * int(z[1])\\nprint(count // 2)\\n\",\n \"(n, m) = map(int, input().split(' '))\\np = m * n\\nk = p // 2\\nprint(k)\\n\",\n \"(M, N) = input('').split()\\n(M, N) = (int(M), int(N))\\nmaximum = M * N // 2\\nprint(maximum)\\n\",\n \"(n, m) = list(map(int, input().split()))\\nc = 0\\nif 1 <= m <= 16 and 1 <= n <= 16:\\n\\twhile True:\\n\\t\\tif n >= 2:\\n\\t\\t\\tn -= 2\\n\\t\\t\\tc += m\\n\\t\\tif n == 1:\\n\\t\\t\\tn -= 1\\n\\t\\t\\tc += int(m / 2)\\n\\t\\tif n == 0:\\n\\t\\t\\tbreak\\nprint(c)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nnum_ds = 0\\nif area == 1:\\n\\tprint('0')\\nelse:\\n\\tfor i in range(1, area, 2):\\n\\t\\tnum_ds += 1\\n\\tprint(num_ds)\\n\",\n \"mn = input()\\nmn = mn.split()\\nfor i in range(2):\\n\\tmn[i] = int(mn[i])\\nsquares = mn[0] * mn[1]\\nprint(squares // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nb = m // 2\\ninitial = b * n\\nremb = m - 2 * b\\nfinalvalue = initial\\nif remb == 1:\\n\\tl = n // 2\\n\\tfinalvalue += l\\nprint(finalvalue)\\n\",\n \"import math\\nn = [int(x) for x in input().split()]\\nr = math.floor(n[0] * n[1] / 2)\\nprint(r)\\n\",\n \"a = input().split()\\na = list(map(int, a))\\nS = a[0] * a[1]\\nnum = S // 2\\nprint(num)\\n\",\n \"n = str(input()).split()\\nmn = int(n[0]) * int(n[1])\\nprint(mn // 2)\\n\",\n \"x = input()\\ny = x.split(' ')\\nz = int(y[0])\\nk = int(y[1])\\ntablero = z * k\\nif tablero % 2 == 0:\\n\\tprint(int(tablero / 2))\\nelse:\\n\\tprint(int((tablero - 1) / 2))\\n\",\n \"def noOfDominos(n, m):\\n\\tif n % 2 == 0:\\n\\t\\treturn n // 2 * m\\n\\telse:\\n\\t\\treturn n // 2 * m + m // 2\\n(n, m) = [int(x) for x in input().split()]\\nprint(noOfDominos(n, m))\\n\",\n \"import sys\\nsides = sys.stdin.readline().rstrip('\\\\n').split(' ')\\nsides = [int(i) for i in sides]\\narea = sides[0] * sides[1]\\nprint(area // 2)\\n\",\n \"s = str(input())\\nm = n = str()\\nk = i = 0\\nfor i in range(len(s)):\\n\\tif s[i] != ' ':\\n\\t\\tm += s[i]\\n\\telse:\\n\\t\\tk = i + 1\\n\\t\\tbreak\\nwhile k != len(s):\\n\\tn += s[k]\\n\\tk += 1\\nm = int(m)\\nn = int(n)\\na = int(m * n * 0.5)\\nprint(a)\\n\",\n \"def dominos(length, width):\\n\\tarea = length * width\\n\\tdomino = area // 2\\n\\treturn domino\\n\\ndef main():\\n\\tinp = input()\\n\\ttemp = inp.split(' ')\\n\\tlength = int(temp[0])\\n\\twidth = int(temp[1])\\n\\tprint(dominos(length, width))\\nmain()\\n\",\n \"def main():\\n\\tmn = input()\\n\\tmn = mn.split(' ')\\n\\tarea = int(int(mn[0]) * int(mn[1]) / 2)\\n\\tprint(area)\\nmain()\\n\",\n \"(m, n) = (int(i) for i in input().split())\\nmd = m // 2\\nmr = m % 2\\nprint(md * n + mr * n // 2)\\n\",\n \"from math import ceil\\n(a, b) = map(int, input().split())\\nif a < b:\\n\\t(a, b) = (b, a)\\nbase = a * (b // 2)\\nif b % 2 != 0:\\n\\tbase += a // 2\\nprint(base)\\n\",\n \"def main():\\n\\t(m, n) = map(int, input().split())\\n\\tboard = [[0 for _ in range(n)] for _ in range(m)]\\n\\tcount = 0\\n\\tfor i in range(m):\\n\\t\\tfor j in range(n - 1):\\n\\t\\t\\tif board[i][j] == board[i][j + 1] == 0:\\n\\t\\t\\t\\t(board[i][j], board[i][j + 1]) = (1, 1)\\n\\t\\t\\t\\tcount += 1\\n\\t\\tif i + 1 < m and board[i][n - 1] == 0:\\n\\t\\t\\t(board[i][n - 1], board[i + 1][n - 1]) = (1, 1)\\n\\t\\t\\tcount += 1\\n\\tprint(count)\\nmain()\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\narea = m * n\\ncount = math.floor(area / 2)\\nprint(count)\\n\",\n \"a = input()\\nx = int(a[0:2])\\ny = int(a[2:5])\\nb = x * y\\nprint(b // 2)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nm = M * N\\nr = m / 2\\nr = int(r)\\nprint(r)\\n\",\n \"(a, b) = [int(x) for x in input().split()]\\nc = 2\\nres = a * b // 2\\nprint(res)\\n\",\n \"mn_string = input()\\nmn_list = mn_string.split(' ')\\nsquares = int(mn_list[0]) * int(mn_list[1])\\nsolution = squares // 2\\nprint(solution)\\n\",\n \"rd = lambda : list(map(int, input().split()))\\n(m, n) = rd()\\nprint(n * m // 2)\\n\",\n \"[m, n] = [int(x) for x in input().split(' ')]\\nprint(f'{m * n // 2}')\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nres = a // 2 * b\\nif a % 2 == 1:\\n\\tres += b // 2\\nprint(res)\\n\",\n \"t = input()\\ni = 0\\nsum = 1\\nformated = t.split(' ')\\nwhile i <= len(formated) - 1:\\n\\tsum = sum * int(formated[i])\\n\\ti += 1\\nprint(sum // 2)\\n\",\n \"import sys\\nlines = list(sys.stdin)\\na = int(lines[0].split()[0])\\nb = int(lines[0].split()[1])\\nprint(a * b // 2)\\n\",\n \"l = [int(e) for e in input().split()]\\nprint(l[0] * l[1] // 2)\\n\",\n \"__author__ = 'zhangxun'\\n\\ndef main():\\n\\tm_n_scale = input()\\n\\tm = int(m_n_scale.split(' ')[0])\\n\\tn = int(m_n_scale.split(' ')[1])\\n\\tcouter = 0\\n\\tif m == 1:\\n\\t\\tcouter += n // 2\\n\\telif m >= 2 and m % 2 == 0:\\n\\t\\tcouter += m // 2 * n\\n\\telse:\\n\\t\\tcouter += m // 2 * n\\n\\t\\tcouter += n // 2\\n\\tprint(couter)\\nmain()\\n\",\n \"(m, n) = map(int, input().split())\\n1 <= m <= n <= 16\\nimport math\\nnum = math.floor(m * n / 2)\\nprint(num)\\n\",\n \"s = list(map(int, input().split(' ')))\\nans = -1\\nif s[0] % 2 == 0:\\n\\tif s[1] % 2 == 0:\\n\\t\\tans = s[0] * s[1] / 2\\n\\telse:\\n\\t\\tans = s[0] * (s[1] - 1) / 2 + s[0] / 2\\nelif s[1] % 2 == 0:\\n\\tans = s[1] * (s[0] - 1) / 2 + s[1] / 2\\nelse:\\n\\tans = (s[0] - 1) * (s[1] - 1) / 2 + (s[0] - 1) / 2 + (s[1] - 1) / 2\\nprint(int(ans))\\n\",\n \"(a, b) = map(int, input().strip().split())\\n\\ndef sol(m, n):\\n\\tif m % 2 == 0:\\n\\t\\treturn m // 2 * n\\n\\telif n % 2 == 0:\\n\\t\\treturn n // 2 * m\\n\\telse:\\n\\t\\treturn m // 2 * n + n // 2\\nprint(sol(a, b))\\n\",\n \"s = input()\\nm = 0\\nn = 0\\nfor i in range(len(s)):\\n\\tif s[i] == ' ':\\n\\t\\tn = m\\n\\t\\tm = 0\\n\\telse:\\n\\t\\tm = m * 10 + int(s[i])\\nprint(n * m // 2)\\n\",\n \"(m, n) = map(int, input().split())\\n\\ndef solve(m, n):\\n\\ttotal = 0\\n\\treturn m * n / 2\\nprint(int(solve(m, n)))\\n\",\n \"(N, M) = map(int, input().split())\\nimport math\\nprint(math.trunc(N * M / 2))\\n\",\n \"a = input().split()\\nindex = int(a[0]) * int(a[1]) // 2\\nprint(index)\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0 or n % 2 == 0:\\n\\tmax_domino = m * n / 2\\nelse:\\n\\tmax_domino = m // 2 * n + n // 2\\nprint(int(max_domino))\\n\",\n \"def solution() -> int:\\n\\t(m, n) = map(int, input().split())\\n\\ts = m * n\\n\\tcnt = 0\\n\\twhile not s <= 1:\\n\\t\\tcnt += 1\\n\\t\\ts -= 2\\n\\treturn cnt\\nprint(solution())\\n\",\n \"def solve():\\n\\t(M, N) = map(int, input().split())\\n\\tprint(M * N // 2)\\nTestcase = 1\\nfor _ in range(Testcase):\\n\\tsolve()\\n\",\n \"import math\\n(n, m) = map(int, input().split())\\nl = 2\\nb = 1\\nx = n / l\\ny = m / b\\nprint(math.floor(x * y))\\n\",\n \"inp = input().split()\\nm = int(inp[0])\\nn = int(inp[1])\\nout = m * n // 2\\nprint(out)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\ndominos = area // 2\\nprint(dominos)\\n\",\n \"(m, n) = input().split()\\nboard_size = int(m) * int(n)\\nif int(m) > int(n) or int(n) > 16:\\n\\tprint('Error')\\nelif int(m) * int() % 2 == 0:\\n\\tprint(int(m) * int(n) // 2)\\nelif int(m) * int(n) % 2 == 1:\\n\\tprint(int(m) * int(n) // 2)\\n\",\n \"(l, b) = input().split()\\nl = int(l)\\nb = int(b)\\nrem = 0\\ncount = 0\\nfor i in range(l):\\n\\tif b % 2 == 0:\\n\\t\\tcount += int(b / 2)\\n\\telse:\\n\\t\\tcount += int(b / 2)\\n\\t\\trem += 1\\ncount += int(rem / 2)\\nprint(count)\\n\",\n \"def main():\\n\\ta = input().split(' ')\\n\\tl = int(a[0])\\n\\tw = int(a[1])\\n\\tl1 = l // 2\\n\\tn = l1 * w + l % 2 * w // 2\\n\\tprint(n)\\nmain()\\n\",\n \"inp = input().split()\\nprint(int(eval(inp[0]) * eval(inp[1]) / 2))\\n\",\n \"a = list(map(int, input().strip().split(' ')))\\nans = a[0] * a[1]\\nans = ans // 2\\nprint(ans)\\n\",\n \"a = [int(x) for x in input().split()]\\nif a[0] < a[1]:\\n\\ttemp = a[0]\\n\\ta[0] = a[1]\\n\\ta[1] = temp\\nres = a[0] // 2 * a[1] + a[0] % 2 * a[1] // 2\\nprint(res)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nz = m * n\\ny = z / 2\\ny = int(y)\\nif 1 <= m <= n <= 16:\\n\\tprint(y)\\nelse:\\n\\tprint('invalid value')\\n\",\n \"(M, N) = [int(x) for x in input('').split()]\\nboard_area = M * N\\ndomino_area = 2\\nprint(board_area // domino_area)\\n\",\n \"from math import ceil\\n(m, n) = map(int, input().split())\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(m * n // 2)\\nelse:\\n\\tprint(max(ceil(m * n / 2) - 1, 0))\\n\",\n \"import sys, bisect, copyreg, copy, statistics, os\\n\\ndef inp():\\n\\treturn sys.stdin.readline().strip()\\n\\ndef IIX():\\n\\treturn (int(x) for x in sys.stdin.readline().split())\\n\\ndef II():\\n\\treturn int(inp())\\n\\ndef LI():\\n\\treturn list(map(int, inp().split()))\\n\\ndef L(x):\\n\\treturn list(x)\\n\\ndef out(var):\\n\\treturn sys.stdout.write(str(var))\\n(m, n) = IIX()\\narea = m * n\\ndominoes = area // 2\\nout(dominoes)\\n\",\n \"(n1, n2) = map(int, input().split())\\nsq = n1 * n2\\ndo = sq // 2\\nprint(do)\\n\",\n \"(uzndk, eny) = map(int, input().split())\\nnmbr_of_dmns = 0\\nif uzndk % 2 == 0:\\n\\tnmbr_of_dmns = uzndk / 2 * eny\\nelif eny % 2 == 0:\\n\\tnmbr_of_dmns = eny // 2 * uzndk\\nelse:\\n\\tnmbr_of_dmns = uzndk // 2 * eny + eny // 2\\nprint(int(nmbr_of_dmns))\\n\",\n \"(m, n) = map(int, input().split())\\nBoard = m * n\\nPieces = 2 * 1\\nnumber = int(Board / Pieces)\\nprint(number)\\n\",\n \"x = input().split()\\ny = 0\\nif x[0] > x[1]:\\n\\ttool = int(x[0])\\n\\tarz = int(x[1])\\nelse:\\n\\ttool = int(x[1])\\n\\tarz = int(x[0])\\nif tool >= 2 and arz >= 1:\\n\\ty = y + tool // 2 * arz // 1\\n\\tif tool % 2 == 1 and arz >= 2:\\n\\t\\ty = y + arz // 2\\nprint(y)\\n\",\n \"data = input('')\\nm = data.find(' ')\\nM = int(data[:m])\\nN = int(data[m + 1:])\\na = 2\\nb = 1\\ndom = int(M * N / (a * b))\\nprint(dom)\\n\",\n \"import math\\n(n, m) = map(int, input().split())\\nz = 0\\nif n == 1 and m == 1:\\n\\tprint(0)\\n\\texit()\\nif n % 2 == 0:\\n\\tz = m * math.floor(n / 2)\\nelif m % 2 == 0:\\n\\tz = n * math.floor(m / 2)\\nelif n > m:\\n\\tz = m * math.floor(n / 2) + math.floor(m / 2)\\nelse:\\n\\tz = n * math.floor(m / 2) + math.floor(n / 2)\\nprint(z)\\n\",\n \"from sys import stdin, stdout\\n(n, m) = [int(y) for y in stdin.readline().split()]\\nprint(int(n * m * 0.5))\\n\",\n \"N = list(map(int, input().split()))\\nprint(N[0] * N[1] // 2)\\n\",\n \"from collections import Counter\\nimport math\\nimport sys\\nfrom bisect import bisect, bisect_left, bisect_right\\n\\ndef input():\\n\\treturn sys.stdin.readline().strip()\\n\\ndef INT():\\n\\treturn int(input())\\n\\ndef MAP():\\n\\treturn map(int, input().split())\\n\\ndef LIST(N=None):\\n\\treturn list(MAP()) if N is None else [INT() for i in range(N)]\\n\\ndef mod():\\n\\treturn 10 ** 9 + 7\\n(n, k) = MAP()\\nans = 0\\nprint(math.floor(n * k / 2))\\n\",\n \"x = input().split()\\nm = int(x[0])\\nn = int(x[1])\\narea = m * n\\nif m % 2 == 0 or n % 2 == 0:\\n\\tevenAns = area / 2\\n\\tprint(int(evenAns))\\nelse:\\n\\toddAns = (area - 1) / 2\\n\\tprint(int(oddAns))\\n\",\n \"(a, b) = map(int, input().strip().split())\\nprint(max(b * (a // 2) + b // 2 * (a % 2), a * (b // 2) + a // 2 * (b % 2)))\\n\",\n \"(m, n) = [int(x) for x in input().strip().split()]\\nprint(int(m * n // 2))\\n\",\n \"(l, b) = map(int, input().split(' '))\\na = 2\\nprint(l * b // a)\\n\",\n \"(n, m) = map(int, input().split())\\ns = n * m\\nsq = 2\\ndom = 0\\nif s % sq == 0:\\n\\tdom = s // sq\\nelse:\\n\\tdom = s // sq\\nprint(dom)\\n\",\n \"import math\\nN = input()\\na = N.split()\\nm = int(a[0])\\nn = int(a[1])\\nq = m % 2\\nw = math.floor(m / 2)\\nif q == 0:\\n\\tx = w * n\\nelse:\\n\\tx = w * n + math.floor(n / 2)\\nprint(x)\\n\",\n \"(m, n) = input().split()\\n(m, n) = [int(m), int(n)]\\not = m / 2 * n\\not = int(ot)\\nprint(ot)\\n\",\n \"import math\\nsize = input()\\n(x, y) = size.split()\\nx = int(x)\\ny = int(y)\\ndominoes = 0\\noffset = 0\\nif x > 1:\\n\\tif not x % 2 == 0:\\n\\t\\toffset = 1\\n\\tdominoes += math.floor((x - offset) / 2 * y)\\nif x == 1 or (offset == 1 and y > 1):\\n\\tdominoes += math.floor(y / 2)\\nprint(dominoes)\\n\",\n \"l = list(map(int, input().split()))\\nM = max(l[0], l[1])\\nN = min(l[0], l[1])\\nx = M // 2 * N + M % 2 * (N // 2)\\nprint(x)\\n\",\n \"def calc_dominee(m, n):\\n\\tif m <= 0 or n <= 0:\\n\\t\\treturn 0\\n\\tif m == 1:\\n\\t\\treturn n // 2\\n\\tif n == 1:\\n\\t\\treturn m // 2\\n\\tif m >= n and n >= 2:\\n\\t\\treturn m + calc_dominee(m, n - 2)\\n\\telse:\\n\\t\\treturn n + calc_dominee(m - 2, n)\\n(M, N) = map(int, input().split())\\nprint(calc_dominee(M, N))\\n\",\n \"(a, b) = map(int, input().split())\\nc = b\\nif a > b:\\n\\tb = a\\n\\ta = c\\nmain_a = a\\nif a % 2 == 0:\\n\\tno_dom = int(a / 2 * b)\\nelse:\\n\\ta -= 1\\n\\tno_dom = int(a / 2 * b)\\nif main_a % 2 != 0 and b % 2 == 0:\\n\\tno_dom += int(b / 2)\\nelif main_a % 2 != 0 and b % 2 != 0:\\n\\tno_dom += int((b - 1) / 2)\\nprint(no_dom)\\n\",\n \"(X, Y) = map(int, input().split())\\n(A, B) = (min(X, Y), max(X, Y))\\nprint(A // 2 * B + A % 2 * (B // 2))\\n\",\n \"(m, n) = input().split()\\nmul = int(m) * int(n)\\nd = mul // 2\\nif m == 1 and n == 1:\\n\\tprint(0)\\nelse:\\n\\tprint(d)\\n\",\n \"temp = input().strip().split()\\nm = int(temp[0])\\nn = int(temp[1])\\nq = m * n // 2\\nprint(q)\\n\",\n \"import math\\nBord = input().split(' ')\\nOppervlakte = 0\\nOppervlakte = int(Bord[0]) * int(Bord[1])\\nprint(math.trunc(Oppervlakte / 2))\\n\",\n \"inp = input()\\nli = list(map(int, inp.split()))\\nm = li[0] * li[1]\\ni = 0\\nsu = 0\\nif li[0] == 0 or li[1] == 0:\\n\\tsu = 0\\nelif li[0] > 0 and li[1] > 0:\\n\\twhile i >= 0:\\n\\t\\tsu = su + 2\\n\\t\\tif su > m:\\n\\t\\t\\tsu = su - 2\\n\\t\\t\\tbreak\\n\\t\\ti = i + 1\\nprint(round(su / 2))\\n\",\n \"line = input()\\na = [int(i) for i in line.split()]\\nprint(a[1] * a[0] // 2)\\n\",\n \"import math as mp\\n(n, m) = map(int, input().split())\\nt = mp.floor(n * m * 0.5)\\nprint(int(t))\\n\",\n \"(m, n) = list(map(int, input().split()))\\ndominoes = 0\\nsqr_covered = 0\\nsqr_extra = 0\\nfor x in range(m):\\n\\tfor y in range(n):\\n\\t\\tsqr_covered += 1\\n\\t\\tif sqr_covered % 2 == 0:\\n\\t\\t\\tdominoes += 1\\nprint(dominoes)\\n\",\n \"def fun(N):\\n\\ts = N[0] * N[1]\\n\\tresult = s // 2\\n\\treturn result\\nN = list(map(int, input().split()))\\nprint(fun(N))\\n\",\n \"board_sizes = list(map(int, input().split()))\\nfirstElement = int(board_sizes[0])\\nsecondElement = int(board_sizes[-1])\\nresult = firstElement * secondElement // (2 * 1)\\nprint(result)\\n\",\n \"import math\\n(rows, col) = map(int, input().split())\\nprint(math.floor(rows * col * 0.5))\\n\",\n \"nk = list(map(int, input().split()))\\nris = nk[0] * nk[1]\\nris -= ris % 2\\nprint(ris // 2)\\n\",\n \"i = list(map(int, input().split()))\\np = i[0]\\nq = i[1]\\nM = ['w' for i in range(p) for j in range(q)]\\nm = len(M) // 2\\nprint(m)\\n\",\n \"import sys\\n\\ndef domino(m, n):\\n\\tprint(m * n // 2)\\ns = sys.stdin.readline().strip('/n')\\ns = ' '.join(s.split())\\nx = s.split(' ')\\nif int(x[0]) <= int(x[1]) and int(x[0]) >= 1 and (int(x[1]) <= 16):\\n\\tdomino(int(x[0]), int(x[1]))\\n\",\n \"(a, b) = map(int, input().strip().split())\\nw = a * b / 2\\nprint(int(w))\\n\",\n \"(m, n) = map(int, input().split())\\nt = m * n\\nsum = t // 2\\nprint('{0}'.format(sum))\\n\",\n \"line = input()\\npieces = line.split()\\na = int(pieces[0])\\nb = int(pieces[1])\\nc = a * b\\nd = int(c / 2)\\nprint(d)\\n\",\n \"(a, b) = map(int, input().split())\\noutput = a * b // 2\\nprint(output)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nd = int(M * N / 2)\\nprint(d)\\n\",\n \"(m, n) = map(int, input().split())\\nsize_board = m * n\\nsize_pieces = 2\\nmax_num = size_board // size_pieces\\nprint(max_num)\\n\",\n \"import math\\ninp = input()\\nnumbers = [int(s) for s in inp.strip().split(' ')]\\nm = numbers[0]\\nn = numbers[1]\\nif n % 2 != 0:\\n\\tprint(math.floor(n / 2) * m + math.floor(m / 2))\\nelse:\\n\\tprint(math.floor(n / 2) * m)\\n\",\n \"import math\\n(a, b) = map(int, input().split())\\nad = 1\\nbd = 2\\na = a * b / (ad * bd)\\na = math.floor(a)\\nprint(a)\\n\",\n \"nm = input().split()\\narea = int(nm[0]) * int(nm[1])\\nprint(int(area / 2))\\n\",\n \"(n, k) = input().split()\\nn = int(n)\\nk = int(k)\\nif k * n % 2 == 0:\\n\\tans = int(k * n / 2)\\nelse:\\n\\tans = int((k * n - 1) / 2)\\nprint(ans)\\n\",\n \"dapigu = str(input())\\ndapigu = dapigu.split(' ')\\nM = int(dapigu[0])\\nN = int(dapigu[1])\\nm = M // 2\\nn = M % 2\\nif n != 0:\\n\\tprint(str(m * N + N // 2))\\nelse:\\n\\tprint(str(m * N))\\n\",\n \"a = input().split(' ')\\nx = int(a[0]) * int(a[1])\\nif x % 2 == 0:\\n\\tprint(int(x / 2))\\nelse:\\n\\tprint(int((x - 1) / 2))\\n\",\n \"inp = input()\\nx = inp.split()\\na = int(x[0]) * int(x[1])\\nx = a % 2\\nif x == 1:\\n\\ta = a - 1\\n\\tprint(int(a / 2))\\nelif x == 0:\\n\\tprint(int(a / 2))\\n\",\n \"(m, n) = input().split()\\nr = eval(m) * eval(n) // 2\\nprint(r)\\n\",\n \"rect = list(map(int, input().split()))\\narea = rect[0] * rect[1]\\nprint(int((area - area % 2) / 2))\\n\",\n \"n = list(map(int, input().split()))\\ncross = n[0] * n[1]\\nresult = cross // 2\\nprint(result)\\n\",\n \"(m1, n) = map(int, input().split())\\nprint(m1 * n // 2)\\n\",\n \"(p, q) = list(map(int, input().split()))\\nr = p * q\\nif r % 2 == 0:\\n\\te = r // 2\\n\\tprint(e)\\nelse:\\n\\to = (r - 1) // 2\\n\\tprint(o)\\n\",\n \"def prob50a(m, n):\\n\\tlength = n // 2\\n\\textrapcs = 0\\n\\tif n % 2 == 1:\\n\\t\\textrapcs = m // 2\\n\\treturn length * m + extrapcs\\n(m, n) = map(int, input().split(' '))\\nresult = prob50a(m, n)\\nprint(result)\\n\",\n \"square = list(map(int, input().split()))\\nanswer = max(square) // 2 * min(square) + max(square) % 2 * (min(square) // 2)\\nprint(answer)\\n\",\n \"s = input()\\nli = s.split()\\nm = int(li[0]) * int(li[1])\\nprint(m // 2)\\n\",\n \"t = input()\\nt_holder = ''\\nfor item in t:\\n\\tif item == ' ':\\n\\t\\tm = int(t_holder)\\n\\t\\tt_holder = ''\\n\\telse:\\n\\t\\tt_holder += item\\nn = int(t_holder)\\nprint(n * m // 2)\\n\",\n \"import math\\nlst = list(map(int, input().split()))\\n(M, N) = [lst[i] for i in range(0, 2)]\\nboardsquare = M * N\\ndomino = 2 * 1\\n1 <= M <= N <= 16\\ntotal = math.floor(boardsquare / domino)\\nprint(total)\\n\",\n \"n = list(map(int, input().split()))\\nx = n[0]\\ny = n[1]\\nif x % 2 != 0 and y % 2 != 0:\\n\\ta = x * y - 1\\n\\tb = a / 2\\n\\tprint(int(b))\\nelse:\\n\\tprint(int(x * y * 0.5))\\n\",\n \"ip = str(input()).split(' ')\\nm = int(ip[0])\\nn = int(ip[1])\\nnum_of_dominos_placed = 0\\n\\ndef print_board():\\n\\tglobal board\\n\\tfor row in board:\\n\\t\\tprint(''.join(row))\\n\\ndef place_domino(row, col):\\n\\tglobal board, num_of_dominos_placed, m, n\\n\\tif board[row][col] == '*':\\n\\t\\tif col + 1 < n and board[row][col + 1] == '*':\\n\\t\\t\\tboard[row][col] = '-'\\n\\t\\t\\tboard[row][col + 1] = '-'\\n\\t\\t\\tnum_of_dominos_placed += 1\\n\\t\\telif row + 1 < m and board[row + 1][col] == '*':\\n\\t\\t\\tboard[row][col] = '|'\\n\\t\\t\\tboard[row + 1][col] = '|'\\n\\t\\t\\tnum_of_dominos_placed += 1\\nboard = []\\nfor row in range(m):\\n\\tboard.append(['*' for col in range(n)])\\nfor row in range(m):\\n\\tfor col in range(n):\\n\\t\\tplace_domino(row, col)\\nprint(num_of_dominos_placed)\\n\",\n \"import math\\n\\ndef domino():\\n\\tn = input().split()\\n\\tarea = int(n[0]) * int(n[1])\\n\\ttotalFilled = math.floor(area / 2)\\n\\tprint(totalFilled)\\ndomino()\\n\",\n \"while True:\\n\\tsize = input()\\n\\tdimensions = size.split(' ')\\n\\ttry:\\n\\t\\tlength = int(dimensions[0])\\n\\t\\twidth = int(dimensions[1])\\n\\texcept ValueError:\\n\\t\\tpass\\n\\telse:\\n\\t\\tbreak\\narea = length * width\\ndominoes = int(area / 2 - area % 2 / 2)\\nprint(dominoes)\\n\",\n \"def mul(a):\\n\\tb = 1\\n\\tfor i in range(len(a)):\\n\\t\\tb *= a[i]\\n\\treturn b\\na = [int(x) for x in input().split()]\\nprint(mul(a) // 2)\\n\",\n \"l = list()\\nwhile True:\\n\\tboard = input()\\n\\tl = board.split(' ')\\n\\tM = int(l[0])\\n\\tN = int(l[1])\\n\\tif 1 <= M <= N <= 16:\\n\\t\\tbreak\\nprint(M * N // 2)\\n\",\n \"data_input = input()\\ndata_input = data_input.split(' ')\\nn = int(data_input[0])\\nm = int(data_input[1])\\nsqrt = n * m\\nres = 0\\nwhile sqrt - 2 >= 0:\\n\\tres += 1\\n\\tsqrt -= 2\\nif sqrt < 0:\\n\\tres -= 1\\nprint(res)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\ns = int(area / 2)\\nprint(s)\\n\",\n \"import sys\\ns = input()\\ns = s.split(' ')\\ns1 = int(s[0])\\ns2 = int(s[1])\\nboard = s1 * s2\\nans = board // 2\\nprint(ans)\\n\",\n \"from sys import stdin\\n\\ndef main():\\n\\t(m, n) = [int(i) for i in stdin.readline().strip().split()]\\n\\tprint(int(m / 2 * n))\\nmain()\\n\",\n \"prompt = input().split(' ')\\nprint(int(prompt[0]) * int(prompt[1]) // 2)\\n\",\n \"(a, b) = map(int, input().split())\\nif a % 2 == 0:\\n\\tprint(b * (a // 2))\\nif b % 2 == 0 and a % 2 != 0:\\n\\tprint(a * (b // 2))\\nif a % 2 != 0 and b % 2 != 0:\\n\\tp = max(a, b)\\n\\tc = p // 2 * min(a, b) + min(a, b) // 2\\n\\tprint(c)\\n\",\n \"ent = input()\\nentrada = ent.split(' ')\\nmult = int(entrada[0]) * int(entrada[1])\\nprint(mult // 2)\\n\",\n \"l = list(map(int, input().strip().split()))\\nn = l[0]\\nm = l[1]\\narea = n * m\\nif area % 2 == 0:\\n\\tans = int(area / 2)\\n\\tprint(ans)\\nelse:\\n\\tans = int((area - 1) / 2)\\n\\tprint(ans)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nresult = 0\\nwhile m > 0:\\n\\tresult += n if m > 1 else math.floor(n / 2)\\n\\tm -= 2\\nprint(result)\\n\",\n \"(m, n) = map(int, input().split())\\nli = [[0 for _ in range(n)] for _ in range(m)]\\nc = 0\\nfor i in range(m):\\n\\tfor j in range(n):\\n\\t\\tif j + 1 < n:\\n\\t\\t\\tif li[i][j] == 0 and li[i][j + 1] == 0:\\n\\t\\t\\t\\tli[i][j] = 1\\n\\t\\t\\t\\tli[i][j + 1] = 1\\n\\t\\t\\t\\tc += 1\\n\\t\\t\\t\\tj = j + 2\\nfor i in range(n):\\n\\tfor j in range(m):\\n\\t\\tif j + 1 < m:\\n\\t\\t\\tif li[j][i] == 0 and li[j + 1][i] == 0:\\n\\t\\t\\t\\tli[j][i] = 1\\n\\t\\t\\t\\tli[j + 1][i] = 1\\n\\t\\t\\t\\tc += 1\\n\\t\\t\\t\\tj = j + 2\\nprint(c)\\n\",\n \"def main():\\n\\tlst = input().split()\\n\\tfor i in range(len(lst)):\\n\\t\\tlst[i] = int(lst[i])\\n\\tif lst[0] <= 1 and lst[1] <= 1:\\n\\t\\tprint(0)\\n\\telif lst[0] == 2:\\n\\t\\tprint(lst[1])\\n\\telif lst[1] == 2:\\n\\t\\tprint(lst[0])\\n\\telse:\\n\\t\\tprint(int(lst[0] * lst[1] / 2))\\nmain()\\n\",\n \"dimension = list(map(int, input().split(' ')))\\nprint(dimension[0] * dimension[1] // 2)\\n\",\n \"import math\\n(m, n) = input().split()\\nvalue = math.floor(int(m) * int(n) / 2)\\nprint(value)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\nif s % 2 == 0:\\n\\ta = s // 2\\n\\tprint(a)\\nelif s % 2 == 1:\\n\\tb = s // 2\\n\\tprint(b)\\n\",\n \"(m1, n1) = input().split()\\nM = int(m1)\\nN = int(n1)\\ntotal = 0\\nif M >= 2:\\n\\tif M / 2 == int(M / 2):\\n\\t\\ttotal += int(M / 2 * N)\\n\\telif N / 2 == int(N / 2):\\n\\t\\ttotal += int(int(M / 2) * N + N / 2)\\n\\telse:\\n\\t\\ttotal += int(int(M / 2) * N + int(N / 2))\\nelse:\\n\\ttotal += int(N / 2)\\nprint(total)\\n\",\n \"g = input()\\nfor i in range(len(g)):\\n\\tif g[i] == ' ':\\n\\t\\tarea = int(g[:i]) * int(g[i + 1:])\\n\\t\\tbreak\\nprint(area // 2)\\n\",\n \"(n, m) = list(map(int, input().split()))\\nmat = n * m\\nprint(int(mat / 2))\\n\",\n \"(m, n) = (int(s) for s in input().split(' '))\\nres = m * n // 2\\nprint(res)\\n\",\n \"import math\\nboard = str(input()).split()\\nM = int(board[0])\\nN = int(board[1])\\na = min(M, N)\\nb = max(M, N)\\nnum = 0\\nwhile a > 1:\\n\\tnum = b * math.floor(a / 2)\\n\\ta = a - 2 * math.floor(a / 2)\\nwhile a == 1:\\n\\tnum = num + math.floor(b / 2)\\n\\ta = 0\\nwhile a == 0:\\n\\tprint(num)\\n\\tbreak\\n\",\n \"(x, y) = map(int, input().split())\\ns = x * y\\nprint(int(s / 2))\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif M % 2 == 0 or N % 2 == 0:\\n\\tprint(M * N // 2)\\nelse:\\n\\tans = max((N - 1) * M // 2 + M // 2, (M - 1) * N // 2 + N // 2)\\n\\tprint(ans)\\n\",\n \"(M, N) = map(int, input().rstrip().split())\\nif M == 1:\\n\\tif N == 1:\\n\\t\\tprint(0)\\n\\telse:\\n\\t\\tprint(N // 2)\\nelse:\\n\\tdominoes = M // 2 * N + (0 if not M % 2 else N // 2)\\n\\tprint(dominoes)\\n\",\n \"a = input()\\ns = a.split()\\nM = int(s[0])\\nN = int(s[1])\\nsquares = M * N\\nprint(squares // 2)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nnumber = area // 2\\nprint(number)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nrect = m * n\\nma = math.floor(rect / 2)\\nprint(ma)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\narr = 0\\narr_gg = 0\\nif m * n % 2 == 0:\\n\\tarr = m * n // 2\\n\\tprint(arr)\\nif m * n % 2 != 0:\\n\\tarr_gg = math.floor(m * n / 2)\\n\\tprint(arr_gg)\\n\",\n \"s = list(map(int, input().split(' ')))\\nM = s[0]\\nN = s[1]\\nsum = M * int(N / 2)\\nif N % 2 == 1:\\n\\tsum = sum + int(M / 2)\\nprint(sum)\\n\",\n \"(width, length) = map(int, input().split())\\nresult = width * length / 2\\nprint(int(result))\\n\",\n \"def fun():\\n\\t(a, b) = map(int, input().strip().split())\\n\\tif not b or not a:\\n\\t\\tprint(0)\\n\\tc = a * b\\n\\td = c // 2\\n\\tprint(d)\\nfun()\\n\",\n \"dimen = input()\\ndimen = dimen.split()\\nm = int(dimen[0])\\nn = int(dimen[1])\\narea = m * n\\nprint(area // 2)\\n\",\n \"(n, m) = input().split()\\n(n, m) = (int(n), int(m))\\nC = n * m\\nprint(C // 2)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif (m >= 1 and m <= 16) and (n >= 1 and n <= 16):\\n\\tarea = m * n\\n\\tprint(area // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nvalue = m * n\\nresult = value // 2\\nprint(result)\\n\",\n \"import sys\\n(m, n) = [int(x) for x in sys.stdin.readline().split()]\\nif m % 2 == 1 and n % 2 == 1:\\n\\tprint((m * n - 1) // 2)\\nelse:\\n\\tprint(m * n // 2)\\n\",\n \"MN = input()\\n(m, n) = MN.split()\\nm = int(m)\\nn = int(n)\\nar = m * n\\nar2 = 2\\ncount = 0\\nwhile ar2 <= ar:\\n\\tar2 += 2\\n\\tcount += 1\\nprint(count)\\n\",\n \"input_str = input().split()\\nres = int(input_str[0]) * int(input_str[1]) // 2\\nprint(res)\\n\",\n \"import sys\\n\\ndef solve(m, n):\\n\\tif m * n % 2 == 0:\\n\\t\\treturn m * n // 2\\n\\telse:\\n\\t\\tx = 0\\n\\t\\tif m == 1:\\n\\t\\t\\treturn n // 2\\n\\t\\telif n == 1:\\n\\t\\t\\treturn m // 2\\n\\t\\tif m % 2 != 0 and n % 2 != 0:\\n\\t\\t\\tif m < n:\\n\\t\\t\\t\\tx = (m - 1) * n // 2\\n\\t\\t\\t\\tx += n // 2\\n\\t\\t\\telse:\\n\\t\\t\\t\\tx = (n - 1) * m // 2\\n\\t\\t\\t\\tx += m // 2\\n\\t\\t\\treturn x\\n\\t\\tif m % 2 != 0:\\n\\t\\t\\tx = (m - 1) * n // 2\\n\\t\\t\\tif m > n:\\n\\t\\t\\t\\tx += m // 2\\n\\t\\t\\telse:\\n\\t\\t\\t\\tx += n // 2\\n\\t\\telse:\\n\\t\\t\\tx = (n - 1) * m // 2\\n\\t\\t\\tif m < n:\\n\\t\\t\\t\\tx += n // 2\\n\\t\\t\\telse:\\n\\t\\t\\t\\tx += m // 2\\n\\t\\treturn x\\nn = sys.stdin.readline()\\nn = n.split(' ')\\nprint(solve(int(n[0]), int(n[1])))\\n\",\n \"import math\\n(m, n) = map(int, input().split(' '))\\ns = 0\\nif m % 2 == 0 or n % 2 == 0:\\n\\ts = n * m / 2\\nelse:\\n\\ts = (m - 1) * n / 2 + math.floor(n / 2)\\nprint(int(s))\\n\",\n \"(M, N) = [int(inputNum) for inputNum in input().split()]\\nprint(int(M * N / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nans = m * n\\nres = math.floor(ans / 2)\\nprint(res)\\n\",\n \"x = input()\\ny = x.split(' ')\\na = []\\nfor i in y:\\n\\ta.append(int(i))\\nprint(a[0] * a[1] // 2)\\n\",\n \"inp = input().split()\\nM = int(inp[0])\\nN = int(inp[1])\\nif M < 2 and N < 2:\\n\\tprint('0')\\nelse:\\n\\tif M % 2 == 0 and M > 1:\\n\\t\\t(am, bm) = (M, 0)\\n\\telse:\\n\\t\\t(am, bm) = (M - 1, 1)\\n\\tif N % 2 == 0 and N > 1:\\n\\t\\t(an, bn) = (N, 0)\\n\\telse:\\n\\t\\t(an, bn) = (N - 1, 1)\\n\\tprint(int(am * an / 2 + bm * (an / 2) + bn * (am / 2)))\\n\",\n \"from sys import stdin, stdout\\n(m, n) = tuple(map(int, stdin.readline().split()))\\nquant = n * m // 2\\nstdout.write(str(quant))\\nexit(0)\\n\",\n \"temp = input().split(' ')\\nlength = int(temp[0])\\nheight = int(temp[1])\\nhorizontal = int(length / 2)\\nif length % 2 == 0:\\n\\tprint(horizontal * height)\\nelse:\\n\\tvertical = int(height / 2)\\n\\tprint(horizontal * height + vertical)\\n\",\n \"x = [int(b) for b in input().split()]\\nprint(x[0] * x[1] // 2)\\n\",\n \"w = input().split(' ')\\nn = int(w[0])\\nk = int(w[1])\\nimport math\\nprint(math.floor(n * k / 2))\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nif 1 <= M <= 16 and 1 <= N <= 16:\\n\\tif M % 2 == 0 or N % 2 == 0:\\n\\t\\tprint(round(M * N / 2))\\n\\telse:\\n\\t\\tprint(round((M * N - 1) / 2))\\n\",\n \"dimensions = list(map(int, input().rstrip().rsplit()))\\n(length, width) = (dimensions[0], dimensions[1])\\nprint(int(length * width / 2))\\n\",\n \"(n, k) = map(int, input().split())\\nprod = n * k\\nif prod % 2 == 0:\\n\\tval = int(prod / 2)\\n\\tprint(val)\\nelse:\\n\\tval = int((prod - 1) / 2)\\n\\tprint(val)\\n\",\n \"arr = list(map(int, input().split()))\\nn = int(arr[0] * arr[1] / 2)\\nprint(n)\\n\",\n \"inputLine = input()\\ninputList = inputLine.split(' ')\\nwidth = int(inputList[0])\\nlength = int(inputList[1])\\nprint(width * length // 2)\\n\",\n \"(a, b) = input().strip().split()\\na = int(a)\\nb = int(b)\\nprint(a * b // 2)\\n\",\n \"marimi = input()\\naria = int(marimi.split()[0]) * int(marimi.split()[1])\\nprint(aria // 2)\\n\",\n \"import math\\n(m, n) = input().split()\\n(m, n) = (int(m), int(n))\\nprint(math.floor(m * n / 2.0))\\n\",\n \"(a, b) = map(int, input().split())\\n\\ndef exa(a):\\n\\tx = int(a / 2)\\n\\ty = a - 2 * x\\n\\treturn (x, y)\\n(a1, a2) = exa(a)\\n(b1, b2) = exa(b)\\nprint(2 * a1 * b1 + a2 * b1 + b2 * a1)\\n\",\n \"(m, n) = map(int, input().split())\\nc = 0\\na = [[0 for i in range(n)] for j in range(m)]\\nfor i in range(m):\\n\\tc = c + a[i].count(0)\\nprint(int(c // 2))\\n\",\n \"inv = input().rstrip()\\nli = inv.split()\\nli = list(map(int, li))\\nar = li[0] * li[1]\\nnum = int(ar / 2)\\nprint(num)\\n\",\n \"import math\\ndimension = input()\\ndim = dimension.split()\\nM = math.floor(int(dim[0]))\\nN = math.floor(int(dim[1]))\\nif M % 2 == 1:\\n\\tprint(int((M - 1) / 2 * N + N / 2))\\nelse:\\n\\tprint(int(M / 2 * N))\\n\",\n \"from math import floor\\n(m, n) = list(map(lambda x: int(x), input().strip().split()))\\nprint(floor(m * n / 2))\\n\",\n \"(M, N) = input().split()\\nnoOfSquares = int(M) * int(N) // 2\\nprint(noOfSquares)\\n\",\n \"src = input()\\nnum = int(src.split()[0]) * int(src.split()[1])\\nif num % 2 == 0:\\n\\tprint(int(num / 2))\\nelse:\\n\\tprint(int((num - 1) / 2))\\n\",\n \"import math\\ns = input().strip().split()\\nm = int(s[0])\\nn = int(s[1])\\nres = math.floor(m * n / 2)\\nprint(res)\\n\",\n \"from math import floor\\n(M, N) = input().strip().split()\\n(M, N) = (int(M), int(N))\\nprint(floor(M * N / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\ndom_n = math.floor(m * n / (2 * 1))\\nprint(dom_n)\\n\",\n \"(m, n) = input().split()\\na = int(m)\\nb = int(n)\\nno = int(a * b / 2)\\nprint(no)\\n\",\n \"A = input().split()\\nm = int(A[0])\\nn = int(A[1])\\nprint(m * n // 2)\\n\",\n \"(p, g) = map(int, input().split())\\nprint(int(g * p / 2))\\n\",\n \"mxn = input().split(' ')\\nmxn = [int(i) for i in mxn]\\nb = [0 for i in range(mxn[0])]\\nboard = [b for i in range(mxn[1])]\\ncount = 0\\nfor i in board:\\n\\tfor j in i:\\n\\t\\tcount += 1\\nr = int(count / 2)\\nprint(r)\\n\",\n \"numbers = [int(n) for n in input().split()]\\nn = numbers[0]\\nm = numbers[1]\\nif n == 1 and m == 1:\\n\\tprint(0)\\nelse:\\n\\tprint(int(m * n) // 2)\\n\",\n \"import math\\nimport os\\nimport random\\nimport re\\nimport sys\\n\\ndef matrixRotation(m, n):\\n\\ta = m * n\\n\\tc = a // 2\\n\\tc = c.__floor__()\\n\\tprint(c)\\nmnr = input().rstrip().split()\\nm = int(mnr[0])\\nn = int(mnr[1])\\nmatrixRotation(m, n)\\n\",\n \"(M, N) = map(int, input().split())\\na = 2 * 1\\nfor i in range(1, 15):\\n\\tb = M * N // a\\nprint(b)\\n\",\n \"(m, n) = map(int, input().split())\\n\\ndef domino(m, n):\\n\\tfor i in range(17):\\n\\t\\treturn m * n // 2\\nprint(domino(m, n))\\n\",\n \"a = input('').split(' ')\\nwidth = int(a[0])\\nlength = int(a[1])\\nsize = width * length\\ndom = int(size / 2)\\nprint(dom)\\n\",\n \"from sys import stdin, stdout\\ninp = [int(x) for x in stdin.read().split()]\\nn = inp.pop(0)\\nk = inp.pop(0)\\nboard = n * k\\ndomino_size = 2\\nmax_domino = board / domino_size\\nmax_domino_result = int(max_domino)\\nstdout.write(str(max_domino_result) + '\\\\n')\\n\",\n \"def main(n, m):\\n\\treturn n * m // 2\\nn_m = input().split()\\nn_m = [int(i) for i in n_m]\\nprint(main(n_m[0], n_m[1]))\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\nif 1 <= m <= n <= 16:\\n\\ta = m * n // 2\\n\\tprint(a)\\n\",\n \"w = input().split(' ')\\na = int(w[0])\\nb = int(w[1])\\nk = 0\\nwhile 2 * (k + 1) <= a * b:\\n\\tk += 1\\nprint(k)\\n\",\n \"def main():\\n\\tfrom sys import stdin, stdout\\n\\t(m, n) = [int(x) for x in input().split()]\\n\\tif m % 2 == 1 and n % 2 == 1:\\n\\t\\tprint('{}'.format((m * n - 1) // 2))\\n\\telse:\\n\\t\\tprint('{}'.format(m * n // 2))\\nmain()\\n\",\n \"n = list(input().split(' '))\\na = int(n[0]) * int(n[1])\\nb = a // 2\\nprint(b)\\n\",\n \"from sys import stdin\\nimport math\\n\\ndef main():\\n\\ttable = [int(x) for x in stdin.readline().split()]\\n\\tprint(math.floor(table[0] * table[1] / 2))\\nmain()\\n\",\n \"inp = list(map(int, input().split()))\\nm = inp[0]\\nn = inp[1]\\narea = m * n\\nres = area // 2\\nprint(res)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\na = m * n\\nb = 2\\nc = a // 2\\nprint(c)\\n\",\n \"number = list(map(int, input().split()))\\nl = number[0] * number[1]\\nprint(l // 2)\\n\",\n \"import math\\na = input()\\n(n, m) = a.split()\\nl = int(n) * int(m) / 2\\nprint(math.floor(l))\\n\",\n \"def solve():\\n\\t(x, y) = list(map(int, input().split()))\\n\\tresult = x * y // 2\\n\\tprint(result)\\nsolve()\\n\",\n \"(x, y) = map(int, input().split())\\nprod = x * y\\nprint(int(prod / 2))\\n\",\n \"(a, b) = input().split()\\n(a, b) = (int(a), int(b))\\nc = a % 2\\nd = b % 2\\nif c == 1 and d == 1:\\n\\tx = (a * b - 1) / 2\\nelse:\\n\\tx = a * b / 2\\nprint('%d' % x)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\np = 2\\nprint(s // p)\\n\",\n \"def calc(a, b):\\n\\tf = a * b // 2\\n\\treturn f\\n(a, b) = map(int, input().split())\\nprint(calc(a, b))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nd = n * (m // 2)\\nif m % 2 != 0:\\n\\td = d + n // 2\\nprint(d)\\n\",\n \"arms = input()\\ndata = arms.split()\\narea = int(data[0]) * int(data[1])\\nmax_placed = area // 2\\nprint(max_placed)\\n\",\n \"nm = input().split()\\nn = int(nm[0])\\nm = int(nm[1])\\np = n * m\\nprint(p // 2)\\n\",\n \"nub = input()\\nnub = nub.split(' ')\\nmul = int(nub[0]) * int(nub[1])\\nif mul % 2 != 0:\\n\\teq = (mul - 1) / 2\\n\\tprint(int(eq))\\nelse:\\n\\teq = mul / 2\\n\\tprint(int(eq))\\n\",\n \"q = input('')\\nt = 0\\ndata = []\\ns = 0\\nwhile t < len(q):\\n\\tif q[t] == ' ':\\n\\t\\tdata = data + [s]\\n\\t\\ts = 0\\n\\telif t == len(q) - 1:\\n\\t\\ts = s * 10 + float(q[t])\\n\\t\\tdata = data + [s]\\n\\telse:\\n\\t\\ts = s * 10 + float(q[t])\\n\\tt = t + 1\\nm = data[0]\\nn = data[1]\\nprint(int(m * n // 2))\\n\",\n \"(a, b) = map(int, input().split())\\nans = int()\\nwhile a >= 2:\\n\\tans = ans + b\\n\\ta -= 2\\nif a == 1:\\n\\tans = ans + b / 2\\nprint(int(ans))\\n\",\n \"count = 0\\nb = list(map(int, input().split()))\\narea = b[0] * b[1]\\nprint(area // 2)\\n\",\n \"l = [int(i) for i in input().split()[:2]]\\nprint(l[0] * l[1] // 2)\\n\",\n \"ip = input()\\nl1 = ip.split(' ')\\nm = int(l1[0])\\nn = int(l1[1])\\nprint(int(m * n * 0.5))\\n\",\n \"(m1, n1) = input().split()\\nm = int(m1)\\nn = int(n1)\\nif 1 <= m <= 16 and 1 <= m <= 16:\\n\\tc = int(m * n / 2)\\n\\tprint(c)\\nelse:\\n\\tprint('dimension is not correct')\\n\",\n \"domino = [int(i) for i in input().split(' ')]\\nprint(int(domino[0] * domino[1] / 2))\\n\",\n \"(l, b) = tuple(map(int, input().split()))\\nprint(l * b // 2)\\n\",\n \"mn = input().split()\\ncounter = 0\\nassert 1 <= int(mn[0]) and int(mn[0]) <= int(mn[1]) and (int(mn[1]) <= 16)\\nprint(int(mn[0]) * int(mn[1]) // 2)\\n\",\n \"i = input().split()\\nprint(int(i[0]) * int(i[1]) // 2)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nif N % 2 == 0 or M % 2 == 0:\\n\\tS = M * N / 2\\nelse:\\n\\tQ = M // 2\\n\\tS = Q * N + N // 2\\nprint(int(S))\\n\",\n \"n = input().split()\\na = int(n[0])\\nb = int(n[1])\\nresult = a * b // 2\\nprint(result)\\n\",\n \"(m, n) = [int(a) for a in input().split()]\\nb = m * n\\nprint((b - b % 2) // 2)\\n\",\n \"(m, n) = map(int, input().split())\\ns = m * n\\nnum = int(s / 2)\\nprint(num)\\n\",\n \"(n, m) = map(int, input().split())\\nK1 = n // 2 * m\\nif n % 2 != 0:\\n\\tK1 = K1 + m // 2\\nprint(K1)\\n\",\n \"(M, N) = [int(i) for i in input().split()]\\nx = int(M * N / 2)\\nprint(x)\\n\",\n \"integer = input()\\nlist_integer = integer.split(' ')\\nx = int(list_integer[0]) * int(list_integer[1])\\ny = x // 2\\nprint(y)\\n\",\n \"import math\\na = input().split()\\nm = int(a[0])\\nn = int(a[1])\\nmaindominos = m * math.floor(n / 2)\\nif n % 2 != 0:\\n\\totherDominos = math.floor(m / 2)\\nelse:\\n\\totherDominos = 0\\nprint(maindominos + otherDominos)\\n\",\n \"(size_of_board_n, size_of_board_m) = [int(i) for i in input().split()]\\nhow_much_space = size_of_board_n * size_of_board_m\\nanswer = how_much_space // 2\\nprint(answer)\\n\",\n \"(M, N) = map(int, input().split())\\nif N / 2 == int(N / 2) or M / 2 == int(M / 2):\\n\\tx = int(M * N / 2)\\nelse:\\n\\tx = int((M * N - 1) / 2)\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\nif 1 <= m <= n <= 16:\\n\\tarea = m * n\\n\\tprint(area // 2)\\n\",\n \"l = []\\n(a, b) = map(int, input().split())\\nif a == 1 and b == 1:\\n\\tl.append(0)\\nelif a == 1 and b == 2 or (a == 2 and b == 1):\\n\\tl.append(1)\\nelse:\\n\\tmmax = max(a, b)\\n\\tmmin = min(a, b)\\n\\tssum = 0\\n\\tif mmin % 2 == 0:\\n\\t\\tssum = mmax // 1 * (mmin // 2)\\n\\telse:\\n\\t\\tssum = mmax // 1 * (mmin // 2) + mmax // 2\\n\\tl.append(ssum)\\nfor i in l:\\n\\tprint(i)\\n\",\n \"(m, n) = map(int, input().split())\\narea = m * n\\nif area % 2 != 0:\\n\\tarea -= 1\\nprint(area // 2)\\n\",\n \"import math\\n(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nif 1 <= M <= N <= 16:\\n\\ta = math.floor(M / 2)\\n\\tb = int(a * N)\\n\\tc = M % 2\\n\\tif c == 0:\\n\\t\\tprint(int(b))\\n\\telse:\\n\\t\\td = N / 2\\n\\t\\tprint(int(b + d))\\nelse:\\n\\tprint('error')\\n\",\n \"a = input().split()\\nb = int(a[0])\\na = int(a[1])\\ns = 0\\ns = s + b // 2 * a\\nif b % 2 == 1:\\n\\ts = s + a // 2\\nprint(s)\\n\",\n \"def domino(m, n):\\n\\treturn m * n // 2\\n\\ndef main():\\n\\ts = input().split()\\n\\tprint(domino(int(s[0]), int(s[-1])))\\nmain()\\n\",\n \"(a, b) = [int(i) for i in input().split()]\\nprint('{:d}'.format(a * b // 2))\\n\",\n \"def domino_layout(m, n):\\n\\tD = m * n // 2\\n\\treturn D\\nl = [int(x) for x in input().split()]\\n(m, n) = l\\nprint(domino_layout(m, n))\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nprint('%d' % (a * b / 2))\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nD = M * N // 2\\nprint(D)\\n\",\n \"import math\\n(x, y) = [int(a) for a in input().split()]\\nans = math.floor(x * y / 2)\\nprint(ans)\\n\",\n \"a = input().split()\\nm = int(a[0])\\nn = int(a[1])\\nb = 0\\nif 1 <= m <= n <= 16:\\n\\tb = m * n // 2\\nprint(b)\\n\",\n \"_ = input().split(' ')\\nprint(int(_[0]) * int(_[1]) // 2)\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\nfinal_list = []\\nfor i in list_we_use:\\n\\tfinal_list.append(int(i))\\nq = final_list[0] * final_list[1]\\nprint(q // 2)\\n\",\n \"def sol(x, y):\\n\\tprint(x * y // 2)\\n(m, n) = input().split()\\nsol(int(m), int(n))\\n\",\n \"n = input().split()\\nsize = int(n[0]) * int(n[1])\\nans = size // 2\\nprint(ans)\\n\",\n \"def solve(M, N):\\n\\ttileArea = 2 * 1\\n\\tboardArea = M * N\\n\\tprint(int(boardArea / tileArea))\\n(M, N) = map(int, input().split())\\nsolve(M, N)\\n\",\n \"(m, n) = map(int, input().split())\\nfor i in range(1, 257):\\n\\tif i * 2 > m * n:\\n\\t\\tprint(i - 1)\\n\\t\\texit()\\n\",\n \"import sys\\n\\ndef rs():\\n\\treturn sys.stdin.readline().rstrip()\\n\\ndef ri():\\n\\treturn int(sys.stdin.readline())\\n\\ndef ria():\\n\\treturn list(map(int, sys.stdin.readline().split()))\\n\\ndef ws(s):\\n\\tsys.stdout.write(s)\\n\\tsys.stdout.write('\\\\n')\\n\\ndef wi(n):\\n\\tsys.stdout.write(str(n))\\n\\tsys.stdout.write('\\\\n')\\n\\ndef wia(a, sep=' '):\\n\\tsys.stdout.write(sep.join([str(x) for x in a]))\\n\\tsys.stdout.write('\\\\n')\\n\\ndef solve(n, m):\\n\\tif n * m % 2 == 0:\\n\\t\\treturn n * m // 2\\n\\treturn min(n, m) * (max(n, m) // 2) + min(n, m) // 2\\n\\ndef main():\\n\\t(n, m) = ria()\\n\\twi(solve(n, m))\\nmain()\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\nsquare = M * N\\nnum = square // 2\\nprint(num)\\n\",\n \"import sys\\n\\ndef main():\\n\\tmatrix = []\\n\\tlista = []\\n\\tn = list(map(int, sys.stdin.readline().strip().split(' ')))\\n\\tmult = n[0] * n[1]\\n\\tresultado = mult // 2\\n\\tprint(resultado)\\nmain()\\n\",\n \"def main():\\n\\t(m, n) = (int(i) for i in input().split())\\n\\tif n == 1 and m == 1:\\n\\t\\tres = 0\\n\\tif m % 2 == 0 or n % 2 == 0:\\n\\t\\tres = n * m // 2\\n\\telse:\\n\\t\\t(m, n) = (n, m) if n > m else (m, n)\\n\\t\\tres = (m - 1) * n // 2 + (n - 1) // 2\\n\\tprint(res)\\nmain()\\n\",\n \"inp = list(map(int, str(input()).split(' ')))\\narea = inp[0] * inp[1]\\nprint(area // 2)\\n\",\n \"def calculate_dominos(length, breadth):\\n\\tresult = 0\\n\\tif length > 1 or breadth > 1:\\n\\t\\tresult += length // 2\\n\\t\\tif length % 2 == 0:\\n\\t\\t\\tremaining_length = 0\\n\\t\\telse:\\n\\t\\t\\tremaining_length = 1\\n\\t\\tresult += (breadth - 1) * result\\n\\t\\tif remaining_length == 1:\\n\\t\\t\\tresult += breadth // 2\\n\\treturn result\\n[length, breadth] = list(map(int, input().strip().split(' ')))\\nresult = calculate_dominos(length, breadth)\\nprint(result)\\n\",\n \"(m, n) = input().split(' ')\\nif int(m) / 2 * int(n) > int(m) * int(n) / 2:\\n\\tprint(int(int(m) / 2 * int(n)))\\nelse:\\n\\tprint(int(int(m) * int(n) / 2))\\n\",\n \"(M, N) = list(map(int, input().split()))\\ndomino_area = 2\\nsqr = M * N\\nprint(sqr // domino_area)\\n\",\n \"(m, n) = map(int, input().split())\\nareal = m * n\\nif areal % 2 == 0:\\n\\tbrikker = areal / 2\\n\\tprint(int(brikker))\\nelse:\\n\\tbrikker = (areal - 1) / 2\\n\\tprint(int(brikker))\\n\",\n \"m = input().split()\\nm = '*'.join(m)\\nm = eval(m)\\nm = m / 2\\nprint(int(m))\\n\",\n \"(a, b) = map(int, input().split())\\nres = a * b\\nold = 0\\ni = 0\\nwhile 2 * i <= res:\\n\\told = i\\n\\ti += 1\\nprint(old)\\n\",\n \"inpt = input().split()\\nm = int(inpt[0])\\nn = int(inpt[1])\\nif (m, n >= 1 and m, n <= 16):\\n\\tprint(int(m * n / 2))\\n\",\n \"(a, b) = [int(i) for i in input().split(' ')]\\nanswer = int()\\nif a < b:\\n\\t(a, b) = (b, a)\\nprint(a * (b // 2) + b % 2 * (a // 2))\\n\",\n \"import math\\nn = list(map(int, input().split()))\\nif n[0] * n[1] % 2 == 0:\\n\\tprint(int(n[0] * n[1] / 2))\\nelse:\\n\\tprint(math.floor(n[0] * n[1] / 2))\\n\",\n \"import math\\n(n, k) = map(int, input().split())\\nif n <= 1 and k <= 1:\\n\\tprint(0)\\nelse:\\n\\tprint(math.floor(n * k * 0.5))\\n\",\n \"size = list(map(int, input().split()))\\na1 = size[1] * size[0]\\nprint(a1 // 2)\\n\",\n \"def func(n, m):\\n\\tif m < 2 and n < 2:\\n\\t\\treturn 0\\n\\tif n == 0 or m == 0:\\n\\t\\treturn 0\\n\\tif n == 1:\\n\\t\\treturn m // 2\\n\\tif m == 1:\\n\\t\\treturn n // 2\\n\\tif n > 1:\\n\\t\\treturn m + func(n - 2, m)\\n\\telse:\\n\\t\\treturn n + func(n, m - 2)\\n(n, m) = map(int, input().split())\\nprint(func(n, m))\\n\",\n \"input1 = input().split()\\n(m, n) = (int(input1[0]), int(input1[-1]))\\nif m * n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"import math\\nreq = input().split(' ')\\nfield = int(req[0]) * int(req[1])\\nres = field / 2\\nprint(math.floor(res))\\n\",\n \"(i, j) = input().split()\\nk = int(i) * int(j)\\nl = k // 2\\nprint(l)\\n\",\n \"Dim = list(map(int, input().split()))\\nif Dim[0] % 2 == 0:\\n\\tNum = Dim[0] / 2 * Dim[1]\\n\\tprint(int(Num))\\nelif Dim[1] % 2 == 0:\\n\\tNum = Dim[1] / 2 * Dim[0]\\n\\tprint(int(Num))\\nelse:\\n\\tNum = (Dim[0] - 1) * Dim[1] / 2 + (Dim[1] - 1) / 2\\n\\tprint(int(Num))\\n\",\n \"from math import floor\\nx = input()\\nx = x.split(' ')\\nm = int(x[0])\\nn = int(x[1])\\nif m % 2 == 0:\\n\\tdn = m / 2 * n\\nelse:\\n\\tdn = (m - 1) / 2 * n + floor(n / 2)\\nprint(int(dn))\\n\",\n \"(m, n) = list(map(int, input().split()))\\nd = m * n // 2\\nprint(d)\\n\",\n \"def main():\\n\\tn_m = str(input())\\n\\tn = int(n_m.split(' ')[0])\\n\\tm = int(n_m.split(' ')[1])\\n\\tcnt = 0\\n\\tsp = n * m\\n\\tcnt = int(sp / 2)\\n\\tprint(cnt)\\nmain()\\n\",\n \"def domino():\\n\\t(a, b) = map(int, input().split())\\n\\tif a * b % 2 == 0:\\n\\t\\tprint(int(a * b / 2))\\n\\telse:\\n\\t\\tprint(a * b // 2)\\ndomino()\\n\",\n \"import sys\\nimport math\\nx = sys.stdin.readline().split()\\ny = int(x[1])\\nx = int(x[0])\\nprint(math.floor(x * y / 2))\\n\",\n \"input = str(input())\\nmultiplication = int(input.split(' ')[0]) * int(input.split(' ')[1])\\nsolution = multiplication / 2\\nprint(int(solution))\\n\",\n \"(M, N) = map(int, input().split())\\ns = M * N\\na = 2 * 1\\nx = s // a\\nprint(x)\\n\",\n \"(x, y) = list(map(int, input().split()))\\nif x * y % 2 == 1:\\n\\tprint((x * y - 1) // 2)\\nelse:\\n\\tprint(x * y // 2)\\n\",\n \"import math\\n(m, n) = tuple(map(int, input().split()))\\nif m == 1:\\n\\tprint(math.floor(n / 2))\\nelif n == 1:\\n\\tprint(math.floor(m / 2))\\nelse:\\n\\tmIsOdd = m % 2 != 0\\n\\tx = math.floor(m / 2)\\n\\ty = 0\\n\\tif mIsOdd:\\n\\t\\ty = math.floor(n / 2)\\n\\tprint(x * n + y)\\n\",\n \"from sys import stdin\\n(m, n) = map(int, stdin.readline().split())\\nif m == 1 and n == 1:\\n\\tprint(0)\\nelif m < n:\\n\\ta = n // 2\\n\\tb = n % 2\\n\\tprint(m * a + m * b // 2)\\nelse:\\n\\ta = m // 2\\n\\tb = m % 2\\n\\tprint(n * a + n * b // 2)\\n\",\n \"m = list(map(int, input().split()))\\nif max(m) % 2 == 0:\\n\\tprint(min(m) * (max(m) // 2))\\nelse:\\n\\tprint(min(m) * (max(m) // 2) + min(m) // 2)\\n\",\n \"M = input().split(' ')\\ndomino = 2\\nhasil = int(M[0]) * int(M[1]) // 2\\nprint(hasil)\\n\",\n \"a = input().strip().split(' ')\\nm = int(a[0])\\nn = int(a[1])\\nif m >= 1 and m <= n and (n <= 16):\\n\\tprint(m * n // 2)\\n\",\n \"def get_max_dominoes(n, m):\\n\\tif n == 1 and m == 1:\\n\\t\\treturn 0\\n\\tif m == 2:\\n\\t\\treturn n\\n\\tif n == 2:\\n\\t\\treturn m\\n\\tif m > n:\\n\\t\\treturn n + get_max_dominoes(n, m - 2)\\n\\treturn m + get_max_dominoes(n - 2, m)\\nsize = [int(i) for i in input().split()]\\nprint(get_max_dominoes(size[0], size[1]))\\n\",\n \"(m, n) = input().split()\\n(l, b) = (int(m), int(n))\\narea = l * b\\nprint(int(area / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nmaxnum = 0\\nif 1 <= m <= n <= 16:\\n\\tarea = m * n\\n\\tif area % 2 == 0:\\n\\t\\tmaxnum = int(area / 2)\\n\\telse:\\n\\t\\tmaxnum = math.floor(area / 2)\\nprint(maxnum)\\n\",\n \"import math\\nx = list(map(int, input().split()))\\nm = x[0] * x[1]\\nprint(math.floor(m / 2))\\n\",\n \"import re, math\\nx = re.split(' ', input())\\nfor i in range(0, len(x)):\\n\\tx[i] = int(x[i])\\nprint(math.floor(x[0] * x[1] / 2))\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\narea = m * n\\ndomino = area // 2\\nprint(domino)\\n\",\n \"(r, c) = map(int, input().split())\\nans = 0\\nr1 = r\\nwhile r1 >= 2:\\n\\tans += c\\n\\tr1 -= 2\\nif r % 2 == 1:\\n\\tans += c // 2\\nprint(ans)\\n\",\n \"input_list = input().split()\\nm = eval(input_list[0])\\nn = eval(input_list[1])\\ncounter = 0\\ncounter += n * (m // 2)\\nif m % 2 == 1:\\n\\tcounter += n // 2\\nprint(counter)\\n\",\n \"a = input()\\n(c, v) = a.split()\\nc = int(c)\\nv = int(v)\\nprint(c * v // 2)\\n\",\n \"import sys\\n(n, m) = map(float, input().split())\\nprint(round(n * m // 2))\\n\",\n \"(side1, side2) = input().split()\\nresult = int(side1) * int(side2) / 2\\nprint(int(result))\\n\",\n \"(n, k) = [int(i) for i in input().split()]\\nar = n * k\\nprint(ar // 2)\\n\",\n \"num_list = list(map(int, input().split()))\\nm = num_list[0]\\nn = num_list[1]\\nif m % 2 == 0:\\n\\tnum = m // 2 * n\\n\\tprint(num)\\nelif n % 2 == 0:\\n\\tnum = n // 2 * m\\n\\tprint(num)\\nelse:\\n\\tnum = m // 2 * n + n // 2\\n\\tprint(num)\\n\",\n \"def answer(m, n):\\n\\tproduct = m * n\\n\\tif product % 2 == 1:\\n\\t\\tans = (product - 1) // 2\\n\\t\\treturn ans\\n\\tans = product // 2\\n\\treturn ans\\nsize = input()\\nsize = size.split(' ')\\nnew = [int(each) for each in size]\\nprint(answer(new[0], new[1]))\\n\",\n \"(b, c) = list(map(int, input().strip().split()[:2]))\\nprint(int(b * c / 2))\\n\",\n \"def tile(x, y):\\n\\treturn x * y // 2\\n(x, y) = list(map(int, input().split(' ')))\\nprint(tile(x, y))\\n\",\n \"(m, n) = map(int, input().split())\\nc = 0\\nfreeCells = 0\\nfor i in range(m):\\n\\tc += n // 2\\n\\tif n / 2 % 1 == 0.5:\\n\\t\\tfreeCells += 1\\n\\t\\tif freeCells == 2:\\n\\t\\t\\tc += 1\\n\\t\\t\\tfreeCells = 0\\nprint(c)\\n\",\n \"class main:\\n\\n\\tdef __init__(self):\\n\\t\\tMN = input()\\n\\t\\tMN = MN.split(' ', 1)\\n\\t\\tM = int(MN[0])\\n\\t\\tN = int(MN[1])\\n\\t\\ts = M * N\\n\\t\\tif s % 2 == 0:\\n\\t\\t\\tdomino = s / 2\\n\\t\\t\\tprint(int(domino))\\n\\t\\telif s % 2 != 0:\\n\\t\\t\\ts = s - 1\\n\\t\\t\\tdomino = s / 2\\n\\t\\t\\tprint(int(domino))\\na = main()\\n\",\n \"lst = [int(x) for x in input().split(' ')]\\nprint(lst[0] * lst[1] // 2)\\n\",\n \"from sys import stdin\\ndata = stdin.readline().split()\\nindex = 0\\nmult = 1\\nresult = 0\\nfor item in data:\\n\\tdata[index] = int(item)\\n\\tindex += 1\\nfor item in data:\\n\\tmult *= item\\nresult = int(mult / 2)\\nprint(result)\\n\",\n \"import math\\n\\ndef piling(mm, nn):\\n\\tif mm % 2 == 0:\\n\\t\\treturn mm / 2 * nn\\n\\telif nn % 2 == 0:\\n\\t\\treturn nn / 2 * mm\\n\\telse:\\n\\t\\treturn piling(mm - 1, nn) + math.floor(nn / 2)\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nprint(int(piling(m, n)))\\n\",\n \"(m, n) = tuple(map(int, input().split()))\\narea = m * n\\nre = area // 2\\nprint(re)\\n\",\n \"(M, N) = input().split()\\nm = int(M)\\nn = int(N)\\narea = m * n\\nprint(area // 2)\\n\",\n \"s = input().split()\\nm = int(s[0])\\nn = int(s[1])\\nar = m * n\\nz = ar // 2\\nprint(z)\\n\",\n \"(N, M) = map(int, input().split())\\nn = N % 2\\nm = M % 2\\nif N == 1:\\n\\tprint(M // 2)\\nelif M == 1:\\n\\tprint(N // 2)\\nelse:\\n\\tprint(int(N * m // 2 + M * n // 2 + (M - m) * (N - n) / 2))\\n\",\n \"import math\\n(m, n) = [int(i) for i in input().split()]\\nif m % 2 == 0:\\n\\tprint(int(m / 2 * n))\\nelse:\\n\\tprint(int((m - 1) / 2 * n + math.floor(n / 2)))\\n\",\n \"(a, b) = map(int, input().split())\\nif a < b:\\n\\tc = a\\n\\ta = b\\n\\tb = c\\nd = a % 2\\ne = b % 2\\nfloat(a)\\nfloat(b)\\nif d == 0 or e == 0:\\n\\tanswer = a * b / 2\\nif d != 0 and e != 0:\\n\\tanswer = (a * b - 1) / 2\\nprint(int(answer))\\n\",\n \"(m, n) = list(map(int, input().split()))\\nx = m // 2\\ny = n // 2\\nprint(min(x * y + (m - x) * (n - y), x * (n - y) + (m - x) * y))\\n\",\n \"(x, k) = [int(x) for x in input().split()]\\narea = x * k\\nprint(area // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\narea_board = m * n\\nprint(area_board // 2)\\n\",\n \"z = [int(x) for x in input().split(' ')]\\nprint(z[0] * z[1] // 2)\\n\",\n \"import sys\\nimport math\\ninputs = sys.stdin.readline().split()\\nm = int(inputs[0])\\nn = int(inputs[1])\\na = m % 2\\nb = n % 2\\nif a == 0:\\n\\tx = m * n\\n\\tx = 0.5 * x\\n\\tx = int(x)\\n\\tprint(x)\\nelif b == 0:\\n\\tx = m * n\\n\\tx = 0.5 * x\\n\\tx = int(x)\\n\\tprint(x)\\nelse:\\n\\te = m - 1 + (n - 1)\\n\\tf = (m - 1) * (n - 1)\\n\\tx = e + f\\n\\tx = 0.5 * x\\n\\tx = int(x)\\n\\tprint(x)\\n\",\n \"(m, n) = [int(__) for __ in input().strip().split()]\\nprint(m // 2 * n + m % 2 * n // 2)\\n\",\n \"n = list(map(int, input().split()))\\nif n[0] % 2 == 0:\\n\\tc = n[0] / 2 * n[1]\\nelif n[1] % 2 == 0:\\n\\tc = n[1] / 2 * n[0]\\nelse:\\n\\tc = (n[0] - 1) / 2 * n[1] + (n[1] - 1) / 2\\nprint(int(c))\\n\",\n \"(a, b) = list(map(int, input().split()))\\nd = a * b\\nif d % 2 == 0:\\n\\teven = d // 2\\n\\tprint(even)\\nelse:\\n\\todd = (d - 1) // 2\\n\\tprint(odd)\\n\",\n \"info = input().split()\\narea = 1\\nfor i in range(0, 2):\\n\\tarea = area * int(info[i])\\nprint(area // 2)\\n\",\n \"ints = input().split()\\nnumber = int(ints[0]) * int(ints[1])\\nif number % 2 == 0:\\n\\tprint(int(number / 2))\\nelse:\\n\\tprint(int((number - 1) / 2))\\n\",\n \"(length_of_board, width_of_board) = input().split()\\nlength_of_board = int(length_of_board)\\nwidth_of_board = int(width_of_board)\\nif length_of_board >= 1 and length_of_board <= 16:\\n\\tif width_of_board >= 1 and width_of_board <= 16:\\n\\t\\tmax_area = length_of_board * width_of_board\\n\\t\\tmax_dominoes = int(max_area / 2)\\n\\t\\tprint(max_dominoes)\\n\",\n \"(n, m) = map(int, input().split())\\nprint(m * n // 2, flush=True)\\n\",\n \"def main():\\n\\t(m, n) = list(map(int, input().split()))\\n\\tif m == n == 1:\\n\\t\\tprint(0)\\n\\telif m == 1:\\n\\t\\tprint(n // 2)\\n\\telif n == 1:\\n\\t\\tprint(m // 2)\\n\\telse:\\n\\t\\tprint(n // 2 * m + m // 2 if n % 2 != 0 else n // 2 * m)\\nmain()\\n\",\n \"n = list(map(int, input().split()))\\nn1 = n[0]\\nn2 = n[1]\\na = 2 * 1\\nb = n1 * n2\\nprint(int(b / a))\\n\",\n \"x = input()\\nx1 = x.split(' ')\\nm = int(x1[0])\\nn = int(x1[1])\\nprint(m * n // 2)\\n\",\n \"(x, y) = [int(z) for z in input().split()]\\nmult = x * y\\nif mult % 2 == 0:\\n\\tprint(int(mult / 2))\\nelse:\\n\\tprint(int((mult - 1) / 2))\\n\",\n \"(length, width) = input().split(' ')\\nlength = int(length)\\nwidth = int(width)\\narea = width * length\\ndominoNumber = 0\\nwhile dominoNumber * 2 + 2 <= area:\\n\\tdominoNumber = dominoNumber + 1\\nprint(dominoNumber)\\n\",\n \"def main():\\n\\t(n, m) = map(int, input().split())\\n\\ttotalSquares = n * m\\n\\tprint(totalSquares // 2)\\nmain()\\n\",\n \"m_n = input().strip().split()\\n(m, n) = (int(m_n[0]), int(m_n[1]))\\nprint(m * n // 2)\\n\",\n \"variables = [int(x) for x in input().split()]\\nwidth = variables[0]\\nheight = variables[1]\\nprint(width * height // 2)\\n\",\n \"x = input()\\nx = x.split(' ')\\nm = int(x[0])\\nn = int(x[1])\\narea = m * n\\nnum = area // 2\\nprint(num)\\n\",\n \"l = lambda : map(int, input().split())\\n(a, b) = l()\\nc = a * b\\nd = c // 2\\nprint(d)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0:\\n\\ttotal = m // 2 * n\\nelse:\\n\\ttotal = m // 2 * n\\n\\tk = n // 2\\n\\ttotal = total + k\\nprint(total)\\n\",\n \"edges = input('')\\nm = edges[0:edges.index(' ')]\\nn = edges[edges.index(' ') + 1:]\\nm = int(m)\\nn = int(n)\\nif m % 2 == 0:\\n\\tyatayKenar1 = int(m / 2)\\n\\tuzunKenar1 = n\\n\\tolasilik1 = yatayKenar1 * uzunKenar1\\nelse:\\n\\tyatayKenar1 = int(m / 2)\\n\\tuzunKenar1 = n\\n\\tolasilik1 = yatayKenar1 * uzunKenar1\\n\\tkalan1 = int(n / 2)\\n\\tolasilik1 += kalan1\\nif n % 2 == 0:\\n\\tyatayKenar2 = m\\n\\tuzunKenar2 = int(n / 2)\\n\\tolasilik2 = yatayKenar2 * uzunKenar2\\nelse:\\n\\tyatayKenar2 = m\\n\\tuzunKenar2 = int(n / 2)\\n\\tolasilik2 = yatayKenar2 * uzunKenar2\\n\\tkalan2 = int(m / 2)\\n\\tolasilik2 += kalan2\\nif olasilik1 > olasilik2:\\n\\tprint(olasilik1)\\nelse:\\n\\tprint(olasilik2)\\n\",\n \"(a, b) = list((int(x) for x in input().split()))\\nc = a * b\\nn = c // 2\\nprint(n)\\n\",\n \"(m, n) = list(map(int, input().split()))\\ns = m * n\\nk = s // 2\\nprint(k)\\n\",\n \"(m, n) = [int(m) for m in input().split()]\\nc = int(m * n)\\nif c % 2 == 0:\\n\\tprint(c // 2)\\nelse:\\n\\tprint(c // 2)\\n\",\n \"(k, l) = map(int, input().split())\\nans = k * l // 2\\nprint(ans)\\n\",\n \"import math\\n(length_m, width_m) = map(int, input().split())\\nboardArea = length_m * width_m\\ndomino = 2\\nprint(math.floor(boardArea / domino))\\n\",\n \"(m, n) = input('').split()\\nm = int(m)\\nn = int(n)\\ncell = m * n\\nprint(cell // 2)\\n\",\n \"L = [int(x) for x in input().split(' ')]\\ntemp = L[0] * L[1]\\nprint(int(temp / 2))\\n\",\n \"m = input()\\nli = m.split()\\na = int(li[0])\\nb = int(li[1])\\nc = a * b / 2\\nprint(int(c))\\n\",\n \"def Main():\\n\\t(n, m) = map(int, input().split())\\n\\tprint(n * m // 2)\\nMain()\\n\",\n \"(n, m) = map(int, input().split())\\nboardArea = n * m\\ndominoArea = 2 * 1\\nprint(int(boardArea / dominoArea))\\n\",\n \"(n, m) = map(int, input().split())\\nc = int(m * n)\\nif c % 2 == 0:\\n\\tz = c / 2\\nelse:\\n\\tz = (c - 1) / 2\\nprint(int(z))\\n\",\n \"(M, N) = map(int, input().split())\\nmulti = M * N\\ncont = 0\\nwhile multi > 1:\\n\\tif multi % 2 == 0:\\n\\t\\tmulti -= 2\\n\\t\\tcont += 1\\n\\telse:\\n\\t\\tmulti -= 1\\nprint(cont)\\n\",\n \"s = input()\\nlst = list(map(int, s.split()))\\na = lst[0]\\nb = lst[1]\\nif a < 2 and b < 2:\\n\\tprint(0)\\nelse:\\n\\tans = a // 1 * (b // 2)\\n\\tif b % 2 == 1 and a >= 2:\\n\\t\\tans += a // 2\\n\\tprint(ans)\\n\",\n \"import os\\n(M, N) = os.read(0, 100000).strip().decode('utf-8').split(' ')\\nprint(int(M) * int(N) // 2)\\n\",\n \"__author__ = 'widoc'\\nimport math\\n(m, n) = map(int, input().split())\\nprint(math.floor(m / 2) * n + m % 2 * math.floor(n / 2))\\n\",\n \"(a, b) = [int(temp) for temp in input().split()]\\nprint(a * b // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nav = m * n\\nprint(av // 2)\\n\",\n \"(m, n) = list(map(int, input().split()))\\nif m * n % 2 == 0:\\n\\tjd = m * n / 2\\n\\tprint(int(jd))\\nelse:\\n\\tjd = m * n / 2\\n\\tessa = jd - 0.5\\n\\tprint(int(essa))\\n\",\n \"(m, n) = input().split(' ')\\nm = int(m)\\nn = int(n)\\na = m * n\\nx = a / 2\\nx = int(x)\\nprint(x)\\n\",\n \"(a, b) = map(int, input().split())\\nnumber = 0\\nif a % 2 == 0 or b % 2 == 0:\\n\\tnumber = int(a * b / 2)\\nelse:\\n\\tnumber = int(a * b // 2)\\nprint(number)\\n\",\n \"(a, b) = input().split(' ')\\nm = int(a)\\nn = int(b)\\nif m % 2 != 0 or n % 2 != 0:\\n\\tif m >= n:\\n\\t\\tx = m // 2\\n\\t\\to = x * n\\n\\t\\td = m % 2 * n // 2\\n\\t\\tprint(int(o + d))\\n\\telse:\\n\\t\\tx = n // 2\\n\\t\\to = x * m\\n\\t\\td = n % 2 * m // 2\\n\\t\\tprint(int(o + d))\\nelif m >= n:\\n\\tx = m // 2\\n\\to = x * n\\n\\tprint(o)\\nelse:\\n\\tx = n // 2\\n\\to = x * m\\n\\tprint(o)\\n\",\n \"(m, n) = input().split(' ')\\nwynik = int(int(m) * int(n) / 2)\\nprint(wynik)\\n\",\n \"a = input()\\nb = a.split(' ')\\nb[0] = int(b[0])\\nb[1] = int(b[1])\\nc = b[0] * b[1]\\nk = c // 2\\nprint(k)\\n\",\n \"mat = list(map(int, input().strip().split()))\\nprint(int(mat[0] * mat[1] / 2))\\n\",\n \"import math\\n\\ndef main():\\n\\t(m, n) = input().split()\\n\\tm = int(m)\\n\\tn = int(n)\\n\\tnum = math.floor(m * n / 2)\\n\\tprint(num)\\nmain()\\n\",\n \"t = lambda : map(int, input().split())\\n(m, n) = t()\\nprint(m * n // 2)\\n\",\n \"(m, n) = [int(val) for val in input().split(' ')]\\ndominoes = m // 2\\ndominoes *= n\\nif m % 2:\\n\\tdominoes += n // 2\\nprint(dominoes)\\n\",\n \"(x, y) = input().split()\\np = int(x) * int(y)\\no = p // 2\\nprint(o)\\n\",\n \"(N, M) = map(int, input().split())\\nnumber = N // 2 * M\\nif N % 2 == 1:\\n\\tnumber = number + M // 2\\nprint(number)\\n\",\n \"(m, n) = map(int, input().split())\\na = m\\nb = n // 2\\ncount = a * b\\nif n % 2 != 0:\\n\\tcount += m // 2\\nprint(count)\\n\",\n \"(N, M) = map(int, input().split())\\nvalue = 0\\nif N % 2 == 0:\\n\\tvalue += N // 2 * M\\nelse:\\n\\tvalue += N // 2 * M + M // 2\\nprint(value)\\n\",\n \"a = list(map(int, input().split()))\\nw = a[0] * a[1]\\nresult = w // 2\\nprint(result)\\n\",\n \"firstInput = input().split()\\nproduct = int(firstInput[0]) * int(firstInput[1])\\nif product % 2 == 0:\\n\\tprint(int(product / 2))\\nelse:\\n\\tprint(int((product - 1) / 2))\\n\",\n \"a = input()\\nli = a.split()\\ns = int(li[0])\\nb = int(li[1])\\nx = s * b\\nres = x // 2\\nprint(res)\\n\",\n \"mn = input()\\n(m, n) = map(lambda x: int(x), mn.split(' '))\\nif m < n:\\n\\t(m, n) = (n, m)\\nodd = n % 2\\nresult = m * (n - odd) // 2\\nresult += odd * (m // 2)\\nprint(result)\\n\",\n \"(n, m) = map(int, input().split())\\ns = m * n\\nans = s // 2\\nprint(ans)\\n\",\n \"def ans(arr):\\n\\treturn mn[0] * mn[1] // 2\\nmn = list(map(int, input().strip().split()))\\nprint(ans(mn))\\n\",\n \"(width, height) = [int(i) for i in input().split()]\\nprint(width * height // 2)\\n\",\n \"line = input()\\ni = int(line.split(' ')[0])\\nj = int(line.split(' ')[1])\\nans = 0\\nif i % 2:\\n\\tans += i // 2 * j\\n\\tans += j // 2\\nelse:\\n\\tans += i / 2 * j\\nprint(int(ans))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nprint(str(int(m * n / 2)))\\n\",\n \"import math\\n(a, b) = list(map(int, input().split()))\\nprint(math.floor(a * b / 2))\\n\",\n \"(m, n) = list(map(int, input().split(' ')))\\nmaxi = int(m * n / 2)\\nprint(maxi)\\n\",\n \"(n, m) = input().split()\\np = int(n) * int(m)\\nd = 2\\ns = 0\\nfor i in range(p):\\n\\tif p < 2:\\n\\t\\tprint(s)\\n\\t\\tbreak\\n\\tp -= d\\n\\ts += 1\\n\",\n \"(w, l) = [int(x) for x in input().split()]\\nif w % 2 == 0 or l % 2 == 0:\\n\\tprint(int(w * l * 0.5))\\nelse:\\n\\tprint(w * l // 2)\\n\",\n \"import math\\nn = list(input().split(' '))\\narea = int(n[0]) * int(n[1])\\nans = math.floor(area / 2)\\nprint(ans)\\n\",\n \"from sys import stdin\\n\\ndef cantidad_dominos(m, n):\\n\\ta = m * n\\n\\tb = a // 2\\n\\treturn b\\n\\ndef main():\\n\\tlinea = stdin.readline().strip()\\n\\twhile len(linea) != 0:\\n\\t\\t(m, n) = [int(x) for x in linea.split()]\\n\\t\\tprint(cantidad_dominos(m, n))\\n\\t\\tlinea = stdin.readline().strip()\\nmain()\\n\",\n \"dim = list(map(int, input().split()))\\nprint(dim[0] * dim[1] // 2)\\n\",\n \"x = input()\\nX = x.split()\\nx0 = int(X[0])\\nx1 = int(X[1])\\nx = x0 * x1 // 2\\nprint(x)\\n\",\n \"sp = input().split(' ')\\n(m, n) = (int(sp[0]), int(sp[1]))\\nif m & 1 == 0:\\n\\tans = m // 2 * n\\nelse:\\n\\tans = m // 2 * n + n // 2\\nprint(ans)\\n\",\n \"list = input().split()\\nnum = [int(x) for x in list]\\nif num[0] % 2 == 0:\\n\\tprint(num[0] // 2 * num[1])\\nelse:\\n\\tprint(num[0] // 2 * num[1] + num[1] // 2)\\n\",\n \"(a, b) = map(int, input().split())\\ns = 2 * 1\\nn = a * b\\nprint(int(n / s))\\n\",\n \"s = input()\\na = s.split()\\nm = int(a[0])\\nn = int(a[1])\\nprod = m * n\\ndom = prod / 2\\nprint(int(dom))\\n\",\n \"s = input()\\ns = s.split(' ')\\nsq = int(s[0]) * int(s[1])\\nprint(sq // 2)\\n\",\n \"values = input().split()\\nprint(int(int(values[0]) * int(values[1]) / 2))\\n\",\n \"(hang, lie) = map(int, input().split())\\nif hang % 2 == 1 and lie % 2 == 1:\\n\\tprint(str(int((hang * lie - 1) / 2)))\\nelse:\\n\\tprint(str(int(hang * lie / 2)))\\n\",\n \"(m, n) = map(int, input().strip().split())\\nx = m * n\\nprint(x // 2)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nd = 2 * 1\\nb = m * n\\nprint(b // d)\\n\",\n \"lst = input()\\nlst = lst.split(' ')\\nn = int(lst[0])\\nm = int(lst[1])\\nprint(m * n // 2)\\n\",\n \"(x, y) = map(int, input().split())\\nt = x * y\\nprint(t // 2)\\n\",\n \"m = input().split()\\np = map(int, m)\\nprint(int(m[0]) * int(m[1]) // 2)\\n\",\n \"measure = list(map(int, input().split(' ')))\\nprint(measure[0] * measure[1] // 2)\\n\",\n \"import math\\n\\ndef count(m, n, ansSoFar):\\n\\tif m >= n:\\n\\t\\tm = m - 2\\n\\t\\tn = n - 1\\n\\telse:\\n\\t\\tn = n - 2\\n\\t\\tm = m - 1\\n\\tif m > -1 and n > -1:\\n\\t\\tansSoFar = ansSoFar + 1\\n\\t\\treturn count(m, n, ansSoFar)\\n\\telse:\\n\\t\\treturn ansSoFar\\n(m, n) = map(int, input().split())\\nprint(math.floor(m * n / 2))\\n\",\n \"l = list(map(int, input().split()))\\nm = l[0]\\nn = l[1]\\nc1 = n * (m // 2)\\nif m % 2 != 0:\\n\\tc1 += n // 2\\nprint(c1)\\n\",\n \"c = input().split()\\nx = eval('*'.join(c)) // 2\\nprint(x)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nA2 = 2\\nif 1 <= M <= N <= 16:\\n\\tA1 = M * N\\n\\tA3 = int(A1 / A2)\\n\\tprint(A3)\\n\",\n \"import sys\\nimport os\\n\\ndef int_array():\\n\\treturn list(map(int, input().strip().split()))\\n\\ndef str_array():\\n\\treturn input().strip().split()\\n\\ndef gcd(a, b):\\n\\tif b == 0:\\n\\t\\treturn a\\n\\treturn gcd(b, a % b)\\n\\ndef take_input():\\n\\tif os.environ.get('check'):\\n\\t\\tsys.stdin = open('input.txt', 'r')\\n\\t\\tsys.stdout = open('output.txt', 'w')\\ntake_input()\\n(n, m) = int_array()\\nprint(n * m // 2)\\n\",\n \"N = list(map(int, input().split()))\\nD = N[0] * N[1]\\nRes = D // 2\\nprint(Res)\\n\",\n \"import sys\\nimport math\\ninput = sys.stdin.readline\\nprint = sys.stdout.write\\n(m, n) = tuple(map(int, input().split()))\\nprint(str(m * n // 2))\\n\",\n \"import math\\ninput_str = input().split()\\nboardSize = int(input_str[0]) * int(input_str[1])\\ntotal = math.floor(boardSize / 2)\\nprint(total)\\n\",\n \"(n, k) = map(int, input().split())\\nb = n * k\\nanswer = b // 2\\nprint(answer)\\n\",\n \"x = input()\\nsez = x.split()\\nm = int(sez[0])\\nn = int(sez[1])\\nzmnoz = m * n\\nif zmnoz % 2 == 0:\\n\\tprint(int(zmnoz / 2))\\nelse:\\n\\tprint(int(zmnoz / 2 - 0.5))\\n\",\n \"import math as m\\n(x, y) = map(int, input().split())\\nz = m.floor(x * y / (1 * 2))\\nprint(z)\\n\",\n \"[m, n] = input().split()\\nm = int(m)\\nn = int(n)\\ni = int(m / 2)\\na = i * n\\nif m % 2 != 0:\\n\\tj = int(n / 2)\\n\\ta += j\\nprint(a)\\n\",\n \"Values = input()\\nValues = Values.split(' ')\\nLength = int(Values[0])\\nBreadth = int(Values[1])\\nArea = Length * Breadth\\nDomino_Area = 2\\nFits = Area / int(Domino_Area)\\nprint(int(Fits))\\n\",\n \"(M, N) = list(map(int, input().split()))\\nif 1 <= M <= N <= 16:\\n\\tresult = M * N // 2\\n\\tprint(result)\\n\",\n \"__author__ = 'Mahsa'\\ninputs = input().split(' ')\\nm = int(inputs[0])\\nn = int(inputs[1])\\nif m % 2 == 0:\\n\\tres = m / 2 * n\\nelif n % 2 == 0:\\n\\tres = n / 2 * m\\nelse:\\n\\tres = (m - 1) / 2 * n + (n - 1) / 2\\nprint(int(res))\\n\",\n \"from math import floor\\n(m, n) = [int(i) for i in input().strip().split()]\\narea = m * n\\nprint(int(floor(area / 2)))\\n\",\n \"import sys\\nmn = sys.stdin.readline().split(' ')\\nm = int(mn[0])\\nn = int(mn[1])\\nmn2 = m * n\\nres = int(mn2 / 2)\\nprint(res)\\n\",\n \"(n, m) = map(int, input().split())\\nif n >= m:\\n\\t(n, m) = (m, n)\\nver = m // 2\\ntot = n * ver\\nrem = m % 2\\next = 0\\nif rem >= 1:\\n\\tif n >= 2:\\n\\t\\tp = n // 2\\n\\t\\text = p * rem\\ntot = tot + ext\\nprint(tot)\\n\",\n \"import math\\nin_str = input().split()\\n(M, N) = (int(in_str[0]), int(in_str[1]))\\nprint(int(M * N / 2))\\n\",\n \"dimensions = input()\\ndimensions = dimensions.split()\\ndimension = []\\nfor i in dimensions:\\n\\tnew_val = int(i)\\n\\tdimension.append(new_val)\\narea = dimension[0] * dimension[1]\\nif area % 2 == 0:\\n\\tno_dominos = area / 2\\nelse:\\n\\tno_dominos = (area - 1) / 2\\nprint(int(no_dominos))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\narea = m * n\\nif area % 2 == 0:\\n\\tnumber = area / 2\\nelse:\\n\\tnumber = (area - 1) / 2\\nc = int(number)\\nprint(c)\\n\",\n \"from functools import reduce\\nprint(reduce(lambda a, b: a * b, map(int, input().split())) // 2)\\n\",\n \"num = list(map(int, input().rstrip().split()))\\nprint(int(num[0] * num[1] / 2))\\n\",\n \"a = lambda x, y: x * y\\n[x, y] = input().split()\\nprint(a(int(x), int(y)) // 2)\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef insr():\\n\\ts = input()\\n\\treturn list(s[:len(s) - 1])\\n\\ndef invr():\\n\\treturn map(int, input().split())\\ninputs = inlt()\\n(M, N) = (inputs[0], inputs[1])\\narea = M * N\\nans = area // 2\\nprint(ans)\\n\",\n \"import sys\\nn = 0\\nfor l in sys.stdin:\\n\\tfor k in l.split():\\n\\t\\tif n == 0:\\n\\t\\t\\tx = int(k)\\n\\t\\t\\tn = n + 1\\n\\t\\telse:\\n\\t\\t\\ty = int(k)\\n\\tprint(x * y // 2)\\n\\tbreak\\n\",\n \"from math import ceil\\n(m, n) = map(int, input().split())\\no = ceil(m * n / 2)\\nif n % 2 != 0:\\n\\tif m % 2 != 0:\\n\\t\\to -= 1\\nprint(o)\\n\",\n \"(M, N) = [int(x) for x in input().split()]\\ns = M * N\\nprint(int(s / 2))\\n\",\n \"(n, m) = list(map(int, input().split()))\\nboard_size = n * m\\nnum = 0\\nif n % 2 == 0 or m % 2 == 0:\\n\\tnum = board_size / 2\\nelif n == 1 and m == 1:\\n\\tnum = 0\\nelse:\\n\\tnum = (board_size - 1) / 2\\nprint(int(num))\\n\",\n \"m = input().split()\\nnum1 = int(m[0])\\nnum2 = int(m[1])\\narea = num1 * num2\\nprint(area // 2)\\n\",\n \"a = input()\\nb = list(map(int, a.split()))\\nM = b[0]\\nN = b[1]\\nif M % 2 == 0 or N % 2 == 0:\\n\\tprint(int(M * N / 2))\\nelse:\\n\\tprint(int((M * N - 1) / 2))\\n\",\n \"from sys import stdin\\ninput = stdin.readline\\n(n, k) = map(int, input().split())\\ndomino = n * k // 2\\nprint(domino)\\n\",\n \"(n, m) = map(int, input().split())\\nmax_side = max(m, n)\\nmin_side = min(m, n)\\nans = min_side * (max_side // 2)\\nif max_side % 2 != 0:\\n\\tans += min_side // 2\\nprint(ans)\\n\",\n \"(n, k) = map(int, input().split())\\no = n * k\\nprint(o // 2)\\n\",\n \"line1 = input()\\nM = int(line1.split(' ')[0])\\nN = int(line1.split(' ')[1])\\nif M * N % 2 == 0 or M * N % 2 == 1:\\n\\tprint(int(M * N / 2))\\n\",\n \"(ms, s) = list(map(int, input().split()))\\nprint(ms * s // 2)\\n\",\n \"def putDomino(tableLength, tableWidth):\\n\\twhile 1 <= tableLength <= tableWidth <= 16:\\n\\t\\ttableSize = tableLength * tableWidth\\n\\t\\tdominoMax = tableSize // 2\\n\\t\\tprint(dominoMax)\\n\\t\\tbreak\\n(x, y) = map(int, input().split())\\nputDomino(x, y)\\n\",\n \"string = input().split(' ')\\nprint(int(int(int(string[0]) * int(string[1])) / 2))\\n\",\n \"s = input()\\nm = []\\nfor x in s.split():\\n\\tm.append(int(x))\\nprint(m[0] * m[1] // 2)\\n\",\n \"domino = input()\\ndomino_list = domino.split(' ')\\ndomino_list = list(map(int, domino_list))\\ndomino_list.sort()\\n(M, N) = domino_list\\nif N % 2 == 0:\\n\\tprint(int(M * (N / 2)))\\nelif N % 2 == 1:\\n\\tprint(int(M * (N // 2) + M // 2))\\n\",\n \"(M, N) = map(int, input().split())\\ns = M * N\\no = s // 2\\nprint(o)\\n\",\n \"(l, b) = list(map(int, input().split()))\\nn1 = l // 2\\ne1 = 0\\ne2 = 0\\nif l - 2 * n1 > 0:\\n\\te1 = 1\\n\\te2 = b // 2\\nprint(n1 * b + e1 * e2)\\n\",\n \"import math\\n(m, n) = input('').split(' ')\\nm = int(m)\\nn = int(n)\\na = math.floor(m / 2)\\nb = math.floor(n / 2)\\nif m % 2 == 0:\\n\\tz = a * n\\nelse:\\n\\tz = a * n + b\\nprint(z)\\n\",\n \"arr = list(map(int, input().split()))\\ncount = 0\\nif arr[0] % 2 == 1:\\n\\tcount += arr[1] // 2\\n\\tarr[0] -= 1\\ncount += arr[0] // 2 * arr[1]\\nprint(count)\\n\",\n \"ch = input()\\nl = ch.split(' ')\\n(M, N) = (eval(l[0]), eval(l[-1]))\\nprint(M * N // 2)\\n\",\n \"rec = [int(s) for s in input().split()]\\nprint(rec[0] * rec[1] // 2)\\n\",\n \"import sys\\nline = sys.stdin.readline().strip().split(' ')\\na = int(line[0])\\nb = int(line[1])\\nprint(a * b // 2)\\n\",\n \"def max_dominos(n, m):\\n\\treturn n * m // 2\\n(n, m) = map(int, input().split())\\nprint(max_dominos(n, m))\\n\",\n \"a = list(map(int, input().split()))\\narea = a[0] * a[1]\\nnum = int(area / 2)\\nprint(num)\\n\",\n \"import math\\n(m, n) = input().split()\\na = int(m)\\nb = int(n)\\nc = a * b\\nd = c / 2\\nprint(math.floor(d))\\n\",\n \"k = list(map(int, input().split()))\\ns = k[0] * k[1] // 2\\nprint(s)\\n\",\n \"def checkSize(s):\\n\\ttotalSquares = s[0] * s[1]\\n\\tprint(int(totalSquares / 2))\\ns = list(map(int, input().split()))\\ncheckSize(s)\\n\",\n \"length = input()\\ntemp = length.split(' ')\\nx = int(temp[0])\\ny = int(temp[1])\\narea = x * y\\ndomino = int(area / 2)\\nprint(domino)\\n\",\n \"m_n = input()\\nx = m_n.split(' ')\\nres = int(x[0]) * int(x[1]) / 2\\nprint(int(res))\\n\",\n \"k = input().split(' ')\\nprint(int(k[0]) * int(k[1]) // 2)\\n\",\n \"import sys\\ns = sys.stdin.read()\\nS = s.split()\\nS = [int(i) for i in S]\\na = S[0] * S[1]\\nif a % 2 == 0:\\n\\tprint(int(a / 2))\\nelse:\\n\\tprint(int((a - 1) / 2))\\n\",\n \"(length, width) = map(int, input().split())\\nif length == 1 and width == 1:\\n\\tprint(0)\\nelif length > width:\\n\\toutput = length // 2 * width + length % 2 * width / 2\\n\\toutput = int(output)\\n\\tprint(output)\\nelse:\\n\\toutput = width // 2 * length + width % 2 * length / 2\\n\\toutput = int(output)\\n\\tprint(output)\\n\",\n \"def Main():\\n\\t(m, n) = [int(i) for i in input().split(' ')]\\n\\tif m * n % 2 == 0:\\n\\t\\treturn m * n // 2\\n\\telse:\\n\\t\\treturn m // 2 * n + n // 2\\nprint(Main())\\n\",\n \"(M, N) = map(int, input().split())\\nP = 2\\nprint(int(M * N // P))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nprint(int(0.5 * m * n))\\n\",\n \"(x, y) = map(int, input().split())\\nprint(round(x * y // 2))\\n\",\n \"dm = input().split()\\nprint(int(dm[0]) * int(dm[1]) // 2)\\n\",\n \"import math\\n(m, k) = map(int, input().split())\\na = m * k\\nif a % 2 == 0:\\n\\tprint(a // 2)\\nelse:\\n\\tprint(math.floor(a / 2))\\n\",\n \"dimension = input()\\nstring = dimension.split(' ')\\narea = int(string[0]) * int(string[1])\\nif area % 2 == 0:\\n\\tanswer = area // 2\\n\\tprint(answer)\\nelse:\\n\\tanswer = (area - 1) // 2\\n\\tprint(answer)\\n\",\n \"n = list(map(int, input().split()))\\n(M, N) = (n[0], n[1])\\ns = M * N\\nprint(int(s / 2))\\n\",\n \"inp = [int(x) for x in input().split()]\\na = inp.pop(0)\\nb = inp.pop(0)\\nx = a * b\\nhasil = x / 2\\nprint(int(hasil))\\n\",\n \"a = [int(e) for e in input().split()]\\nif a[0] * a[1] % 2 == 0:\\n\\tprint(int(a[0] * a[1] / 2))\\nelse:\\n\\tprint(int((a[0] * a[1] - 1) / 2))\\n\",\n \"parameters = input().split()\\n(m, n) = (int(parameters[0]), int(parameters[1]))\\nresult = 0\\nif m > 1 and n > 1:\\n\\tresult = m // 2 * (n // 2) * 2\\n\\tif m % 2 != 0 and n % 2 != 0:\\n\\t\\tresult += n // 2 + m // 2\\n\\telif m % 2 != 0:\\n\\t\\tresult += n // 2\\n\\telif n % 2 != 0:\\n\\t\\tresult += m // 2\\nelif m > 1:\\n\\tresult = m // 2\\nelif n > 1:\\n\\tresult = n // 2\\nprint(result)\\n\",\n \"mang = list(input().split())\\ndominoes = int(mang[0]) * int(mang[1]) // 2\\nprint(dominoes)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nD = M * N / 2\\nprint(math.floor(D))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ndominos = 2\\nsol = 0\\narea = m * n\\nwhile dominos <= area:\\n\\tsol = sol + 1\\n\\tdominos = dominos + 2\\nprint(sol)\\n\",\n \"a = input()\\na = a.split()\\nM = int(a[0])\\nN = int(a[1])\\nb = N * M\\nc = b // 2\\nprint(c)\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nnum_dominos = 0\\nif n == m:\\n\\tif n > 3:\\n\\t\\tif n % 2 == 0:\\n\\t\\t\\tfor i in range(int(n / 2)):\\n\\t\\t\\t\\tnum_dominos += n\\n\\t\\telse:\\n\\t\\t\\tfor i in range(n // 2):\\n\\t\\t\\t\\tnum_dominos += n\\n\\t\\t\\tnum_dominos += n // 2\\n\\telif n > 2:\\n\\t\\tnum_dominos += n\\n\\t\\tnum_dominos += m % 2\\n\\telif n == 2:\\n\\t\\tnum_dominos += n\\n\\telif n < 2:\\n\\t\\tnum_dominos = 0\\nelif n > m:\\n\\tnum_dominos += n\\n\\tif m > 3:\\n\\t\\tif m % 2 == 0:\\n\\t\\t\\tfor i in range(m // 2 - 1):\\n\\t\\t\\t\\tnum_dominos += n\\n\\t\\telse:\\n\\t\\t\\tfor i in range(m // 2 - 1):\\n\\t\\t\\t\\tnum_dominos += n\\n\\t\\t\\tnum_dominos += n // 2\\n\\telif m > 2:\\n\\t\\tif n % 2 != 0:\\n\\t\\t\\tnum_dominos += n // 2\\n\\t\\telif n % 2 == 0:\\n\\t\\t\\tnum_dominos += n // 2\\n\\telif m == 2:\\n\\t\\tnum_dominos += 0\\n\\telif m == 1:\\n\\t\\tnum_dominos -= n\\n\\t\\tnum_dominos += n // 2\\n\\telif m <= 0:\\n\\t\\tnum_dominos = 0\\nelif m > n:\\n\\tnum_dominos += m\\n\\tif n > 3:\\n\\t\\tif n % 2 == 0:\\n\\t\\t\\tfor i in range(n // 2 - 1):\\n\\t\\t\\t\\tnum_dominos += m\\n\\t\\telse:\\n\\t\\t\\tfor i in range(n // 2 - 1):\\n\\t\\t\\t\\tnum_dominos += m\\n\\t\\t\\tnum_dominos += m // 2\\n\\telif n > 2:\\n\\t\\tif m % 2 != 0:\\n\\t\\t\\tnum_dominos += m // 2\\n\\t\\telif m % 2 == 0:\\n\\t\\t\\tnum_dominos += m // 2\\n\\telif n == 2:\\n\\t\\tnum_dominos += 0\\n\\telif n == 1:\\n\\t\\tnum_dominos -= m\\n\\t\\tnum_dominos += m // 2\\n\\telif n <= 0:\\n\\t\\tnum_dominos = 0\\nprint(num_dominos)\\n\",\n \"inp = input()\\nm = int(inp.split()[0])\\nn = int(inp.split()[1])\\nif m % 2 == 1 and n % 2 == 1:\\n\\tans = (m * n - 1) / 2\\nelse:\\n\\tans = m * n / 2\\nprint(int(ans))\\n\",\n \"(x, y) = map(int, input().split())\\nxx = x // 2\\nyy = y // 1\\nsum1 = xx * yy\\nif x - xx * 2 >= 1:\\n\\ty1 = y // 2\\n\\tsum1 = sum1 + y1 * 1\\nprint(sum1)\\n\",\n \"x = input().split()\\ntot = 1\\nfor item in x:\\n\\ttot *= int(item)\\nprint(tot // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nboard_area = m * n\\nprint(board_area // 2)\\n\",\n \"try:\\n\\t(a, b) = list(map(int, input().split()))\\n\\tc = a * b\\n\\td = c // 2\\n\\te = int(d)\\n\\tprint(e)\\nexcept:\\n\\tpass\\n\",\n \"def main():\\n\\t(m, n) = [int(x) for x in input().split(' ')]\\n\\tarea = m * n\\n\\tif area % 2 == 0:\\n\\t\\tdominos = area / 2\\n\\telse:\\n\\t\\tdominos = (area - 1) / 2\\n\\tprint(int(dominos))\\nmain()\\n\",\n \"(m, n) = input().split(' ')\\ntotal_squares = int(m) * int(n)\\nprint(int(total_squares / 2))\\n\",\n \"(square_size1, square_size2) = map(int, input().split())\\nprint(int(square_size1 * square_size2 / 2))\\n\",\n \"(m, N) = map(int, input().split())\\nprint(m * N // 2)\\n\",\n \"(m, n) = map(int, input().split())\\na = m // 2\\nb = n\\nans = a * b\\nempty = m % 2\\nif empty == 1:\\n\\tans = ans + n // 2\\nprint(ans)\\n\",\n \"import sys\\n(n, m) = map(int, sys.stdin.readline().strip().split())\\nprint(n * m // 2)\\n\",\n \"def f(a):\\n\\treturn int(a)\\na = input().split()\\na.sort(key=f)\\nb = 0\\nif int(a[0]) % 2 == 0:\\n\\tprint(int(a[0]) // 2 * int(a[1]))\\nelse:\\n\\tb += int(a[0]) // 2 * int(a[1])\\n\\tprint(b + int(a[1]) // 2)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nkol = int(m / 2) * n\\nif m % 2:\\n\\tkol += int(n / 2)\\nprint(kol)\\n\",\n \"import math\\n(m, n) = list(map(int, input().split()))\\ne = m * n\\nw = 2 * 1\\nprint(e // w)\\n\",\n \"lines = input().split()\\nn = int(lines[0])\\nm = int(lines[1])\\na = 0\\nif n % 2 == 0 or m % 2 == 0:\\n\\ta = int(m * n / 2)\\n\\tprint(a)\\nelif n == 1:\\n\\ta = int((m - 1) / 2)\\n\\tprint(a)\\nelse:\\n\\ta = int((n - 1) * m / 2 + (m - 1) / 2)\\n\\tprint(a)\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nlop = True\\ni = 1\\nwhile lop == True:\\n\\tif m * n == 2 * i:\\n\\t\\tprint(i)\\n\\t\\tlop = False\\n\\telif m * n < 2 * i:\\n\\t\\tprint(i - 1)\\n\\t\\tlop = False\\n\\telse:\\n\\t\\ti += 1\\n\",\n \"(m, n) = map(int, input().split())\\nx = m % 2\\nt = int(m / 2) * n\\nif x == 1:\\n\\ts = t + int(n / 2)\\nelse:\\n\\ts = t\\nprint(int(s))\\n\",\n \"print(int(eval(input().replace(' ', '*')) / 2))\\n\",\n \"import random\\nimport sys\\nimport os\\n(w, x) = input().split(' ')\\nw = int(w)\\nx = int(x)\\nprint(w * x // 2)\\n\",\n \"def find_max_dominos(a, b):\\n\\tresult = int(a * b / 2)\\n\\treturn result\\n(a, b) = map(int, input().split(' '))\\nprint(find_max_dominos(a, b))\\n\",\n \"(x, y) = list(map(int, input().split()))\\ntotal = print(int(x * y / 2 - 0.5 if x * y % 2 != 0 else x * y / 2))\\n\",\n \"board = [int(dim) for dim in input().split()]\\narea = board[0] * board[1]\\ndominos = 1\\nwhile dominos * 2 <= area:\\n\\tdominos += 1\\nprint(dominos - 1)\\n\",\n \"MN = input().split()\\nM = int(MN[0])\\nN = int(MN[1])\\na = max(M, N)\\nb = min(M, N)\\nAll = 0\\nwhile b >= 1:\\n\\th = b * int(a / 2)\\n\\tAll = All + h\\n\\tt = a\\n\\ta = max(a % 2, b)\\n\\tb = min(t % 2, b)\\n\\tif a == 1 and b == 1:\\n\\t\\tbreak\\nprint(All)\\n\",\n \"import math\\n[M, N] = [int(s) for s in input().split(' ')]\\nans = math.floor(M * N / 2)\\nprint(ans)\\n\",\n \"a = input()\\nb = a.split(' ')\\nc = int(b[0])\\nd = int(b[1])\\nh = c * d\\nk = h / 2\\nif type(k) == int():\\n\\tk = k\\nelse:\\n\\tk = int(k)\\nprint(k)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nis_even = n % 2 == 0\\nresult = n // 2 * m\\nif not is_even:\\n\\tresult = result + m // 2\\nprint(result)\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef invr():\\n\\treturn list(map(int, input().split()))\\ninput1 = invr()\\nareaOFBoard = input1[0] * input1[1]\\nareaOfDominoes = 2\\nres = areaOFBoard // areaOfDominoes\\nprint(res)\\n\",\n \"(m, n) = input().split()\\nar1 = int(m) * int(n)\\nar2 = 2 * 1\\ni = 0\\nwhile ar2 * i <= ar1:\\n\\tmaxm = i\\n\\ti = i + 1\\nprint(maxm)\\n\",\n \"(x, y) = [int(a) for a in input().split()]\\nz = x * y\\nd = z // 2\\nprint(d)\\n\",\n \"import sys\\n\\ndef int_split(target, delimiter=' '):\\n\\treturn [int(x) for x in target.split(delimiter)]\\nMAX_SIZE = 16\\n(m, n) = int_split(sys.stdin.readline())\\nprint(m * n // 2)\\n\",\n \"input_data = input()\\nlist_we_use = input_data.split(' ')\\nm = []\\nfor i in list_we_use:\\n\\tm.append(int(i))\\nj = m[0] * m[1]\\nprint(j // 2)\\n\",\n \"(n, m) = list(map(int, input().split()))\\nnum = n // 2 * m\\nif n % 2 == 1:\\n\\tnum += m // 2\\nprint(num)\\n\",\n \"input_s = input()\\ninput_list = input_s.split(' ')\\nm = int(input_list[0])\\nn = int(input_list[1])\\nresult = m // 2 * n + m % 2 * (n // 2)\\nprint(result)\\n\",\n \"ein = input('')\\neing = ein.split(' ')\\na = int(eing[0])\\nb = int(eing[-1])\\nprint(a * b // 2)\\n\",\n \"(m, n) = input().split()\\nreq = int(m) * int(n)\\ncount = 0\\nwhile req - 2 > -1:\\n\\tcount += 1\\n\\treq -= 2\\nprint(count)\\n\",\n \"import sys\\n\\ndef gets():\\n\\treturn sys.stdin.readline().strip()\\n\\ndef get():\\n\\treturn int(sys.stdin.readline().strip())\\n\\ndef geti():\\n\\treturn map(int, sys.stdin.readline().strip().split())\\n\\ndef getli():\\n\\treturn list(map(int, sys.stdin.readline().strip().split()))\\n(m, n) = geti()\\nprint(m * n // 2)\\n\",\n \"(n, m) = [int(i) for i in input().split(' ')]\\nif not n % 2 or not m % 2:\\n\\tif not n % 2:\\n\\t\\tprint(int(n / 2) * m)\\n\\telse:\\n\\t\\tprint(int(m / 2) * n)\\nelse:\\n\\tif n < m:\\n\\t\\t(n, m) = (m, n)\\n\\tprint(int(n / 2) * m + int(m / 2))\\n\",\n \"board_size = input().split()\\nM = int(board_size[0])\\nN = int(board_size[1])\\nif M % 2 == 0 and N % 2 == 0 or (M % 2 != 0 and N % 2 == 0):\\n\\tprint(N // 2 * M)\\nelif M % 2 == 0 and N % 2 != 0:\\n\\tprint(M // 2 * N)\\nelif M % 2 != 0 and N % 2 != 0:\\n\\tprint(M * N // 2)\\n\",\n \"from sys import stdin, stdout\\nfrom math import floor\\n\\ndef main():\\n\\t(m, n) = [int(i) for i in stdin.readline().split()]\\n\\tstdout.write(str(floor(m * n / 2)) + '\\\\n')\\nmain()\\n\",\n \"import os\\n(m, n) = list(map(int, input().rstrip().split()))\\nprint(m * n // 2)\\n\",\n \"(m, n) = list(map(int, input().rstrip().split()))\\nbor = m * n\\nprint(bor // 2)\\n\",\n \"from math import ceil\\nq = input().split(' ')\\nm = int(q[0])\\nn = int(q[1])\\nanswer = m * n // 2\\nprint(answer)\\n\",\n \"a = input()\\n(w, h) = list(map(int, str(a).split(' ')))\\nif w % 2 == 1 and h % 2 == 1:\\n\\tprint(int((w - 1) * h / 2) + int((h - 1) / 2))\\nelse:\\n\\tprint(int(w * h / 2))\\n\",\n \"board_sides = list(map(int, input().split()))\\nif 1 <= board_sides[0] <= board_sides[1] <= 16:\\n\\toutput = board_sides[0] * board_sides[1] // 2\\n\\tprint(output)\\n\",\n \"l = list(map(int, input().split(' ')))\\nM = l[0]\\nN = l[1]\\nprint(int(M * N / 2))\\n\",\n \"def solve(m, n):\\n\\ttileArea = 2 * 1\\n\\tborderArea = m * n\\n\\treturn int(borderArea / tileArea)\\n(m, n) = map(int, input().split())\\nprint(solve(m, n))\\n\",\n \"(m, n) = [int(i) for i in input().split(' ')]\\nd = m * (n // 2) + n % 2 * (m // 2)\\nprint(d)\\n\",\n \"class CodeforcesTask50ASolution:\\n\\n\\tdef __init__(self):\\n\\t\\tself.result = ''\\n\\t\\tself.size = []\\n\\n\\tdef read_input(self):\\n\\t\\tself.size = [int(x) for x in input().split(' ')]\\n\\n\\tdef process_task(self):\\n\\t\\tself.result = str(self.size[0] * self.size[1] // 2)\\n\\n\\tdef get_result(self):\\n\\t\\treturn self.result\\nSolution = CodeforcesTask50ASolution()\\nSolution.read_input()\\nSolution.process_task()\\nprint(Solution.get_result())\\n\",\n \"from sys import stdin\\nm = list(map(int, stdin.readline().strip().split()))\\na = m[0]\\nb = m[1]\\nprint(a * b // 2)\\n\",\n \"from math import floor\\n(N, K) = [int(x) for x in input().strip().split(' ')]\\nprint(floor(N * K / 2))\\n\",\n \"def main():\\n\\tline = input()\\n\\tarray = line.split(' ')\\n\\tm = int(array[0])\\n\\tn = int(array[1])\\n\\tprint(int(m * n / 2))\\nmain()\\n\",\n \"(m, n) = map(int, input().split())\\nd = m // 2 * n\\nif m % 2 == 1:\\n\\td += n // 2\\nprint(d)\\n\",\n \"(n, m) = map(int, input().split())\\nif n % 2 == 0 and m % 2 == 0:\\n\\tsol = int(n * m / 2)\\n\\tprint(sol)\\nelif n % 2 == 0 and m % 2 != 0:\\n\\tsol = int(n / 2 * m)\\n\\tprint(sol)\\nelif n % 2 != 0 and m % 2 == 0:\\n\\tsol = int(m / 2 * n)\\n\\tprint(sol)\\nelse:\\n\\tsol = (n * m - 1) / 2\\n\\tsols = int(sol)\\n\\tprint(sols)\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nx = m * n\\ny = 2 * 1\\nprint(x // y)\\n\",\n \"count = 1\\nboard = input()\\nboardlist = board.split(' ')\\nfor i in boardlist:\\n\\tcount *= int(i)\\nprint(count // 2)\\n\",\n \"import math\\nx = input().split()\\nm = int(x[0])\\nn = int(x[1])\\ny = m * n\\nresult = math.floor(y / 2)\\nprint(result)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nprint((str(int(n * m / 2)), str(m * int(n / 2) + int(m / 2)))[n * m % 2 != 0])\\n\",\n \"(h, w) = map(int, input().split())\\nprint(h * w // 2)\\n\",\n \"pieces = input().split()\\na = int(pieces[0])\\nb = int(pieces[1])\\nn = a * b // 2\\nprint(n)\\n\",\n \"def howManyDominos(N, M):\\n\\treturn N * M // 2\\n(N, M) = [int(i) for i in input().split()]\\nprint(howManyDominos(N, M))\\n\",\n \"from math import floor\\na = list(map(int, input().split()))\\nx = floor(a[0] * a[1] / 2)\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nsum = 0\\nwhile a > 0:\\n\\ta = a - 2\\n\\tif a >= 0:\\n\\t\\tsum = sum + 1\\nprint(sum)\\n\",\n \"def Domino_piling(M, N):\\n\\tboard_size = M * N\\n\\tpieces = 2 * 1\\n\\tmaximal_number_of_dominoes = board_size // pieces\\n\\tprint(maximal_number_of_dominoes)\\n(M, N) = map(int, input().split())\\nDomino_piling(M, N)\\n\",\n \"import math\\nboard_size_inputs = input()\\nlength = int(board_size_inputs.split(' ')[0])\\nbreadth = int(board_size_inputs.split(' ')[1])\\nboard_size = length * breadth\\nsquares = math.floor(board_size / 2)\\nprint(squares)\\n\",\n \"a = input()\\na = a.split(' ')\\nm = int(a[0])\\nn = int(a[1])\\nsq = m * n\\ndom = sq / 2\\nprint('%d' % dom)\\n\",\n \"import math\\n(m, n) = input().split()\\n(m, n) = [int(m), int(n)]\\ntotal_area = m * n\\ndominos = math.floor(m * n / 2)\\nprint(dominos)\\n\",\n \"strs = input()\\nstrs = strs.split(' ')\\nn = int(strs[0])\\nm = int(strs[1])\\nprint(int(n * m / 2))\\n\",\n \"import sys\\ni = list(map(int, sys.stdin.readlines()[0].split()))\\na = i[0] // 2 * i[1]\\nif i[0] % 2 != 0:\\n\\ta += i[1] // 2\\nprint(a)\\n\",\n \"def Main():\\n\\t(m, n) = map(int, input().split(' '))\\n\\tval = m * n\\n\\tcnt = int(val / 2)\\n\\tprint(cnt)\\nMain()\\n\",\n \"(m, n) = map(int, input().split())\\nboard = m * n\\nTd = 2\\nnumber_of_dominos = board // Td\\nprint(number_of_dominos)\\n\",\n \"s = str(input())\\nj = list(map(int, s.split(' ')))\\nM = int(j[0])\\nN = int(j[-1])\\nif M % 2 == 0 or N % 2 == 0:\\n\\tw = M * N / 2\\nelse:\\n\\tw = (M * N - 1) / 2\\nprint(int(w))\\n\",\n \"(A, B) = input().split()\\n(a, b) = (int(A), int(B))\\nn = int(a * b / 2)\\nprint(n)\\n\",\n \"import sys\\nimport math\\nimport os\\n(n, m) = map(int, input().split())\\nprint(int(m * n / 2))\\n\",\n \"import math\\n\\ndef function(arr, k):\\n\\tprint(math.floor(m * n / 2))\\nl = list(map(int, input().rstrip().split()))\\nm = l[0]\\nn = l[1]\\nfunction(m, n)\\n\",\n \"num_array = input().split()\\nnum1 = int(num_array[0])\\nnum2 = int(num_array[1])\\nprint(int(num1 * num2 / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nta = 2 * 1\\nba = m * n\\nprint(int(ba / ta))\\n\",\n \"a = str(input())\\ns = a.split(' ')\\nn = int(s[0])\\nm = int(s[1])\\nprint(n // 2 * m + m // 2 * (n % 2))\\n\",\n \"n = input().split()\\nif int(n[0]) * int(n[1]) / 2 == 0:\\n\\tPrint(int(n[0]) * int(n[1]) / 2)\\nelse:\\n\\tprint(int(int(n[0]) * int(n[1]) / 2))\\n\",\n \"sq = input().split()\\nsize = int(sq[0]) * int(sq[1])\\nprint(size // 2)\\n\",\n \"def coverBoard(m, n):\\n\\treturn m * n // 2\\n(m, n) = input().split(' ')\\nprint(coverBoard(int(m), int(n)))\\n\",\n \"(n, m) = map(int, input().split())\\nd = n * m\\nt = d // 2\\nprint(t)\\n\",\n \"s = input()\\n(n, m) = s.split()\\nn = int(n)\\nm = int(m)\\nif (n % 2 == 0) | (m % 2 == 0):\\n\\tprint(n * m // 2)\\n\\texit()\\nprint((n * m - 1) // 2)\\n\",\n \"def program():\\n\\tpass\\n(width, height) = list(map(int, input().strip().split()))\\nsize = width * height\\nprint(size // 2)\\n\",\n \"def list_input():\\n\\treturn list(map(int, input().split()))\\n\\ndef multiple_input():\\n\\treturn map(int, input().split())\\n(a, b) = multiple_input()\\nans = a * b\\nprint(ans // 2)\\n\",\n \"s = input()\\n(m, n) = s.split()\\nm = int(m)\\nn = int(n)\\nb = m * n\\na = b // 2\\nprint(a)\\n\",\n \"params = [int(i) for i in input().split()]\\narea = params[0] * params[1]\\ndominos = area // 2\\nprint(dominos)\\n\",\n \"def solve(m, n):\\n\\treturn m * n // 2\\n(m, n) = list(map(int, input().split()))\\nprint(solve(m, n))\\n\",\n \"MN = input().split()\\nS = int(MN[0]) * int(MN[1])\\nprint(S // 2)\\n\",\n \"boardSizeList = list(map(int, input().split()))\\nm = boardSizeList[0]\\nn = boardSizeList[1]\\nboardSize = m * n\\nif boardSize % 2 == 1:\\n\\tusableSpace = boardSize - 1\\nelse:\\n\\tusableSpace = boardSize\\nanswer = int(usableSpace / 2)\\nprint(answer)\\n\",\n \"job = input().split()\\n(m, n) = (int(job[0]), int(job[1]))\\nprint(int(m * n / 2))\\n\",\n \"a = []\\ntt = str()\\nb = []\\ns = str(input()).replace(' ', ',')\\nfor i in range(len(s)):\\n\\tif s[i] != ',':\\n\\t\\ttt = tt + s[i]\\n\\telse:\\n\\t\\ta.append(tt)\\n\\t\\ttt = ''\\na.append(tt)\\nfor i in a:\\n\\tif i != ',':\\n\\t\\tb.append(i)\\nsun = int(b[0]) * int(b[1])\\nif sun == 1:\\n\\tout = 0\\nelse:\\n\\tout = sun // 2\\nprint(out)\\n\",\n \"(n, m) = map(int, input().strip().split(' '))\\nif m == 0 or n == 0:\\n\\tprint(min(m, n))\\nelif m == 1 or n == 1:\\n\\tprint(max(m, n) // 2)\\nelif min(m, n) % 2 == 0:\\n\\tprint(max(m, n) * (min(m, n) // 2))\\nelse:\\n\\tprint(max(m, n) * (min(m, n) // 2) + max(m, n) // 2)\\n\",\n \"A = str(input())\\n(a, b) = A.split()\\na = int(a)\\nb = int(b)\\nx = b // 2\\nif b % 2 == 1:\\n\\ty = a // 2\\n\\tanswer = x * a + y\\nelse:\\n\\tanswer = x * a\\nprint(answer)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nnum_of_squares = M * N\\nans = math.floor(num_of_squares * 0.5)\\nprint(ans)\\n\",\n \"def read_numbers():\\n\\treturn [int(x) for x in input().split()]\\n(x, y) = read_numbers()\\nk = x * y\\nl = k // 2\\nprint(l)\\n\",\n \"lis = list(map(int, input().split()))\\narea = lis[0] * lis[1]\\nprint(area // 2)\\n\",\n \"lst = [int(x) for x in input().split()]\\nm = lst[0]\\nn = lst[1]\\noverall = 0\\nprint(m * n // 2)\\n\",\n \"import math\\n(x, y) = map(int, input().split())\\nif x % 2 != 0 and y % 2 != 0:\\n\\tres = math.floor(y / 2) * x + math.floor(x / 2)\\n\\tprint(res)\\nelif x % 2 == 0 and y % 2 == 0:\\n\\tres = x * y // 2\\n\\tprint(res)\\nelse:\\n\\tres = x * y // 2\\n\\tprint(res)\\n\",\n \"(a, b) = [int(x) for x in input('').split()]\\na_e = a % 2 == 0\\nb_e = b % 2 == 0\\nif a_e | b_e:\\n\\tres = a * b / 2\\nelse:\\n\\tres = (a * b - 1) / 2\\nprint(int(res))\\n\",\n \"def checkSide(bigger, lesser):\\n\\tv1 = bigger / 2\\n\\tv2 = lesser\\n\\treturn int(v1 * v2)\\ninp = input().split()\\nboardSize = int(inp[0]) * int(inp[1])\\nresult = list(map(int, inp))\\nresult.sort()\\nbigger = int(inp[1])\\nlesser = int(inp[0])\\nprint(checkSide(bigger, lesser))\\n\",\n \"x = input()\\nxx = x.split()\\nm = int(xx[0])\\nn = int(xx[1])\\ntend = int(0)\\n\\ndef eveneven():\\n\\ttend = int(m / 2) * int(n / 1)\\n\\tprint(int(tend))\\n\\treturn\\n\\ndef evenodd():\\n\\ttend = int(m / 2) * int(n / 1)\\n\\tprint(int(tend))\\n\\treturn\\n\\ndef oddeven():\\n\\ttend = int(m / 1) * int(n / 2)\\n\\tprint(int(tend))\\n\\treturn\\n\\ndef oddodd():\\n\\ttend = (n * m - 1) / 2\\n\\tprint(int(tend))\\n\\treturn\\nif m == 1 and n == 1:\\n\\tprint('0')\\nelif m == 3 and n == 3:\\n\\tprint('4')\\nelif m % 2 == 0 and n % 2 == 0:\\n\\teveneven()\\nelif m % 2 == 0 and n % 2 == 1:\\n\\tevenodd()\\nelif m % 2 == 1 and n % 2 == 0:\\n\\toddeven()\\nelif m % 2 == 1 and n % 2 == 1:\\n\\toddodd()\\n\",\n \"def main():\\n\\t(board_width, board_height) = map(int, input().split())\\n\\t(dominos_x, dominos_y, dominos_extra) = (0, 0, 0)\\n\\tif board_width > 1:\\n\\t\\tdominos_x = int(board_width / 2)\\n\\t\\tdominos_y = board_height\\n\\t\\tif board_width % 2 == 1:\\n\\t\\t\\tdominos_extra = int(board_height / 2)\\n\\telif board_height > board_width:\\n\\t\\tdominos_x = 1\\n\\t\\tdominos_y = int(board_height / 2)\\n\\ttotal_dominos = dominos_x * dominos_y + dominos_extra\\n\\tprint(total_dominos)\\nmain()\\n\",\n \"mn = list(input().split())\\nm = int(mn[0])\\nn = int(mn[1])\\ncount = 0\\nif m % 2 == 0 and n % 2 == 0:\\n\\tcount = int(n * m / 2)\\nif m % 2 == 0 and n % 2 != 0:\\n\\tcount = int((n - 1) * m / 2 + int(m / 2))\\nif m % 2 != 0 and n % 2 == 0:\\n\\tcount = int((m - 1) * n / 2 + int(n / 2))\\nelse:\\n\\tcount = int((m - 1) * (n - 1) / 2 + int(n / 2) + int(m / 2))\\nprint(count)\\n\",\n \"l = [int(x) for x in input().split()]\\n(n, m) = (l[0], l[1])\\nmn = min(n, m)\\nmx = max(n, m)\\nprint(mn // 2 * mx + mn % 2 * (mx // 2))\\n\",\n \"(n, m) = list(map(int, input().split()))\\nx = n * m\\nif x % 2 is 1:\\n\\tx -= 1\\nans = x / 2\\nprint(int(ans))\\n\",\n \"(a, b) = map(int, input().split())\\nprint(a * b // 2)\\nexit(0)\\n\",\n \"import math as math\\nstring = input().split(' ')\\nm = int(string[0])\\nn = int(string[1])\\nprint(math.floor(m * n / 2))\\n\",\n \"(M, N) = map(int, input().split())\\ntotal_squares = M * N\\ndominoes = total_squares // 2\\nprint(dominoes)\\n\",\n \"(m, n) = input().split()\\nM = int(m)\\nN = int(n)\\nnum = M * N // 2\\nprint(num)\\n\",\n \"(s, m) = map(int, input().split())\\nprint(s * m // 2)\\n\",\n \"(w1, w2) = input().split()\\nm = int(w1)\\nn = int(w2)\\nmaxdominos = m * n // 2\\nprint(maxdominos)\\n\",\n \"(M, N) = list(map(int, input().split()))\\nsize = M * N\\ntotal = size // 2\\nprint(total)\\n\",\n \"(m, n) = map(int, input().split())\\nz = m * n\\nnum = m * n / 2\\nprint(int(num))\\n\",\n \"x = input('')\\ne = x.split(' ')\\nd = float(e[0]) * float(e[1])\\nf = (d - d % 2) / 2\\nprint(int(f))\\n\",\n \"(M, N) = list(map(int, input().split()))\\ns0 = M * N\\nr = s0 % 2\\nprint(int((s0 - r) / 2))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\na1 = m * n\\nprint(a1 // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nx = m // 2\\ny = n // 2\\nans1 = x * n + (m - 2 * x) * y\\nans2 = y * m + (n - 2 * y) * x\\nprint(max(ans1, ans2))\\n\",\n \"import math\\n\\nclass P50A:\\n\\n\\tdef __init__(self):\\n\\t\\tself.board_width = None\\n\\t\\tself.board_height = None\\n\\t\\tself.solution = None\\n\\n\\tdef parse_input(self):\\n\\t\\t(self.board_width, self.board_height) = (int(i) for i in input().split())\\n\\n\\tdef solve(self):\\n\\t\\tself.solution = math.floor(self.board_height * self.board_width / 2)\\n\\n\\tdef get_solution(self):\\n\\t\\treturn self.solution\\np_50A = P50A()\\np_50A.parse_input()\\np_50A.solve()\\nprint(p_50A.get_solution())\\n\",\n \"a = input()\\nb = a.split()\\nc = int(b[0])\\nd = int(b[1])\\ne = c * d // 2\\nprint(e)\\n\",\n \"import math\\n\\ndef solution():\\n\\t(m, n) = [int(x) for x in input().split()]\\n\\tp = math.floor(m / 2)\\n\\tq = math.floor(n / 2)\\n\\ts = 2 * p * q\\n\\tif m % 2 == 1 and n % 2 == 1:\\n\\t\\ts += p + q\\n\\telif m % 2 == 1 and n % 2 == 0:\\n\\t\\ts += q\\n\\telif m % 2 == 0 and n % 2 == 1:\\n\\t\\ts += p\\n\\tprint(s)\\nsolution()\\n\",\n \"g = lambda : map(int, input().split())\\n(m, n) = g()\\nprint(n * m // 2)\\n\",\n \"import math\\n(m, n) = [int(x) for x in input().split()]\\ns = m * n\\nnumber = math.floor(s / 2)\\nprint(number)\\n\",\n \"import sys\\ninput = sys.stdin.readline\\n\\ndef main():\\n\\ti = inlt()\\n\\tans = int(i[0] / 2) * i[1]\\n\\tif i[0] % 2 == 1:\\n\\t\\tans += int(i[1] / 2)\\n\\tprint(ans)\\n\\ndef inp():\\n\\treturn int(input())\\n\\ndef inlt():\\n\\treturn list(map(int, input().split()))\\n\\ndef instr():\\n\\treturn ''.join(insr())\\n\\ndef insr():\\n\\ts = input()\\n\\treturn list(s[:len(s) - 1])\\n\\ndef invr():\\n\\treturn map(int, input().split())\\nmain()\\n\",\n \"a = [int(s) for s in input().split()]\\nr = a[0] * a[1]\\nr = int(r)\\nn = 0\\nn = int(n)\\nwhile r > 1:\\n\\tr -= 2\\n\\tn += 1\\nprint(n)\\n\",\n \"(n, k) = tuple(map(int, input().split()))\\nprint(n * k // 2)\\n\",\n \"(m, n) = map(int, input().split(' '))\\ntile_area = 2 * 1\\nboard_area = m * n\\nprint(int(board_area / tile_area))\\n\",\n \"(n, m) = map(int, input().split())\\nif n & 1 and m & 1:\\n\\tprint(n * m - 1 >> 1)\\nelse:\\n\\tprint(n * m >> 1)\\n\",\n \"a = input()\\n(c, d) = map(int, a.split())\\nf = c * d\\ng = f // 2\\nprint(g)\\n\",\n \"from sys import stdin\\n(m, n) = map(int, input().split())\\nprint(m * n // 2)\\n\",\n \"i = lambda : map(int, input().split())\\n(m, n) = i()\\nprint([int(m * n / 2), 0][m == 1 and n == 1])\\n\",\n \"L = 2\\nB = 1\\n\\ndef dominoes(row, col, l=L, b=B):\\n\\tarea = row * col\\n\\tarea_domino = L * b\\n\\tnum = area // area_domino\\n\\treturn num\\n(row, col) = [int(x) for x in input().split()]\\nnum = dominoes(row, col)\\nprint(num)\\n\",\n \"(n, k) = map(int, input().split())\\nb = n * k\\nresult = int(b / 2)\\nprint(result)\\n\",\n \"(M, n) = map(int, input().split())\\nArea = M * n\\nDomino = 2\\nprint(Area // Domino)\\n\",\n \"(m, n) = input().split()\\nprod = int(m) * int(n)\\nprint(prod // 2)\\n\",\n \"s = input()\\nk = []\\nk = s.split(' ')\\n(m, n) = (int(k[0]), int(k[1]))\\narea = m * n\\nn = area // 2\\nprint(n)\\n\",\n \"def convert(string):\\n\\treturn string.split(sep=None, maxsplit=-1)\\ns = convert(input())\\nM = int(s[0])\\nN = int(s[1])\\nprint(M * N // 2)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nnum = math.floor(M * N / 2)\\nprint(num)\\n\",\n \"nm = input()\\nnm = nm.split(' ')\\nn = int(nm[0])\\nm = int(nm[1])\\nd = 2\\nf = 0\\nif n == 1 and m == 1:\\n\\tprint('0')\\nelse:\\n\\tif n % 2 == 0:\\n\\t\\trow = n // 2\\n\\t\\tf = row * m\\n\\telse:\\n\\t\\trow = n // 2\\n\\t\\tf = row * m\\n\\t\\tcol = m // 2\\n\\t\\tf = f + col\\n\\tprint(f)\\n\",\n \"(longueur, largeur) = map(int, input().split())\\nair = longueur * largeur\\nresultat = int(air / 2)\\nprint(resultat)\\n\",\n \"(n, m) = list(map(int, input().split()))\\nimport math\\nb = n * m\\nif b % 2 == 0:\\n\\tprint(int(n * m / 2))\\nelse:\\n\\ta = math.ceil(int(b / 2))\\n\\tprint(a)\\n\",\n \"wymiary = input()\\nxy = wymiary.split(' ')\\nx = int(xy[0])\\ny = int(xy[1])\\npolePlanszy = x * y\\ndomino = polePlanszy / 2\\nif domino % 1 == 0.5:\\n\\tdomino = domino - 0.5\\ndomino = int(domino)\\nprint(f'{domino}')\\n\",\n \"str1 = input()\\nlist1 = str1.split(' ')\\nM = int(list1[0])\\nN = int(list1[1])\\nnum1 = N // 2\\nif not N % 2:\\n\\tmaxnum = M * num1\\nelse:\\n\\tmaxnum = M * num1 + M // 2\\nprint(maxnum)\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nb = M * N\\nif b % 2 == 0:\\n\\tprint(b // 2)\\nelse:\\n\\tk = math.floor(b // 2)\\n\\tprint(k)\\n\",\n \"import sys\\nimport math\\n(a, b) = map(int, sys.stdin.readline().split())\\nprint(math.floor(int(a) * int(b) / 2))\\n\",\n \"nums = [int(x) for x in input().split()]\\nprint(nums[0] * nums[1] // 2)\\n\",\n \"inp = input()\\ntheLst = inp.split()\\nm = int(theLst[0])\\nn = int(theLst[1])\\ndefault = 2\\narea = m * n\\nif area % 2 == 0:\\n\\tprint(int(area / default))\\nelse:\\n\\tprint(int((area - 1) / default))\\n\",\n \"def area(m, n):\\n\\tarea = m * n\\n\\tresult = int(area / 2)\\n\\treturn result\\nm_n = input()\\nm_n_list = m_n.split()\\nfor i in range(0, len(m_n_list)):\\n\\tm_n_list[i] = int(m_n_list[i])\\ndominoes = area(m_n_list[0], m_n_list[1])\\nprint(dominoes)\\n\",\n \"(m, n) = map(int, input().split())\\nadd = 0\\nif m % 2 != 0:\\n\\tif n % 2 == 0:\\n\\t\\tt = m\\n\\t\\tm = n\\n\\t\\tn = t\\n\\telse:\\n\\t\\tadd = int(n / 2)\\n\\t\\tm = m - 1\\nans = int(m * n / 2 + add)\\nprint(ans)\\n\",\n \"(M, N) = map(int, input().split())\\nsize = M * N\\ndominoes = size // 2\\nprint(dominoes)\\n\",\n \"import sys, itertools, math\\n\\ndef ia():\\n\\treturn [int(i) for i in sys.stdin.readline().strip().split(' ')]\\n\\ndef ii():\\n\\treturn int(sys.stdin.readline().strip())\\n(m, n) = ia()\\nprint(m * n // 2)\\n\",\n \"data = list(map(int, input().split()))\\nif data[0] % 2 == 0:\\n\\tcant = data[0] / 2 * data[1]\\nelif data[1] % 2 == 0:\\n\\tcant = data[1] / 2 * data[0]\\nelif data[0] > data[1]:\\n\\tcant = int((data[0] - 1) / 2 * data[1] + (data[1] - 1) / 2)\\nelse:\\n\\tcant = int((data[1] - 1) / 2 * data[0] + (data[0] - 1) / 2)\\nprint(int(cant))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nboard = [[0 for _ in range(n)] for i in range(m)]\\n\\ndef pilling(matrix):\\n\\tdomino = 0\\n\\tfor i in range(len(matrix)):\\n\\t\\tfor j in range(len(matrix[0]) - 1):\\n\\t\\t\\tif matrix[i][j] == matrix[i][j + 1] == 0:\\n\\t\\t\\t\\tdomino += 1\\n\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\tmatrix[i][j + 1] = 1\\n\\tfor i in range(len(matrix) - 1):\\n\\t\\tfor j in range(len(matrix[0])):\\n\\t\\t\\tif matrix[i][j] == matrix[i + 1][j] == 0:\\n\\t\\t\\t\\tdomino += 1\\n\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\tmatrix[i + 1][j] = 1\\n\\treturn domino\\nprint(pilling(board))\\n\",\n \"string = input('')\\n(m, n) = string.split(' ')\\ncount = int(m) * int(n)\\nresult = count // 2\\nprint(result)\\n\",\n \"import sys\\nlocal_launch = False\\ntry:\\n\\topen('LOCAL').read()\\n\\tlocal_launch = True\\nexcept:\\n\\tpass\\ninput_data = open('INPUT.txt').read() if local_launch else sys.stdin.read()\\ndone = {'i': 0}\\ntokens = input_data.split()\\n\\ndef next_token():\\n\\tresult = tokens[done['i']]\\n\\tdone['i'] += 1\\n\\treturn result\\n\\ndef next_int():\\n\\treturn int(next_token())\\n\\ndef next_str():\\n\\treturn next_token()\\nm = next_int()\\nn = next_int()\\nu = m * n\\nif u % 2 == 0:\\n\\tu = u // 2\\n\\tprint(u)\\nelse:\\n\\tu = (u - 1) // 2\\n\\tprint(u)\\n\",\n \"inp = input().split()\\nn = int(inp[0])\\nm = int(inp[1])\\ns = 0\\nif n % 2 == 0 and m % 2 == 0:\\n\\ts = n * m / 2\\nelif n % 2 == 1 and m % 2 == 0:\\n\\tk = n\\n\\tn = m\\n\\tm = k\\nif m == 1:\\n\\ts = int(n / 2)\\nif s == 0:\\n\\tk = 0\\n\\tif n % 2 == 1:\\n\\t\\tk = 1\\n\\t\\tn -= 1\\n\\tm -= 1\\n\\ts = n * m / 2\\n\\ts += n / 2\\n\\tif k:\\n\\t\\ts += m / 2\\nprint(int(s))\\n\",\n \"import math\\na = []\\nc = 0\\nb = 0\\n(n, m) = map(int, input().split())\\nc = int(n / 2) * m\\nif n % 2 != 0:\\n\\tc += int(m / 2)\\nprint(c)\\n\",\n \"(M, N) = input().split()\\nM_integer = int(M)\\nN_integer = int(N)\\ntotal_area = M_integer * N_integer\\nnumber_dominoes = int(total_area / 2)\\nprint(number_dominoes)\\n\",\n \"(n, m) = sorted([int(_) for _ in input().split()])\\nif n % 2 == 1 and m % 2 == 1:\\n\\tprint(m * (n // 2) + m // 2)\\nelif n % 2 == 0:\\n\\tprint(m * (n // 2))\\nelse:\\n\\tprint(n * (m // 2))\\n\",\n \"k = input().split()\\nM = int(k[0])\\nN = int(k[1])\\nk = M * N // 2\\nprint(k)\\n\",\n \"A = input().split(' ')\\nflaeche = 1\\nfor i in range(2):\\n\\tA[i] = int(A[i])\\n\\tflaeche *= A[i]\\nanzahl_dominos = int(flaeche / 2)\\nprint(anzahl_dominos)\\n\",\n \"import math\\nstring = input()\\narr = string.split(' ')\\narea = int(arr[0]) * int(arr[1])\\nprint(int(math.floor(area / 2)))\\n\",\n \"import math\\n(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nv1 = a * b\\nprint(int(v1 / 2))\\n\",\n \"E = input().split()\\nM = int(E[0])\\nN = int(E[1])\\nprint(M * N // 2)\\n\",\n \"x = input()\\nx = x.split()\\ny = int(x[0])\\nz = int(x[1])\\nq = y // 2\\nw = y % 2\\ne = w * z // 2\\nres = q * z + e\\nprint(res)\\n\",\n \"(m, n) = map(int, input().split())\\nboard = m * n\\ndomino = 2 * 1\\nprint(board // domino)\\n\",\n \"(x, y) = [int(j) for j in input().split(' ')]\\nprint(int(x * y / 2))\\n\",\n \"(a, b) = input().split(' ')\\n(a, b) = (int(a), int(b))\\nm = a * b\\nc = 0\\nn = 0\\nwhile n <= m:\\n\\tn += 2\\n\\tc += 1\\nprint(c - 1)\\n\",\n \"(n, m) = map(int, input().split())\\nz = n * m\\nif z % 2 == 0:\\n\\tnumber_of_dom = int(z / 2)\\nelif z % 2 != 0:\\n\\tnumber_of_dom = int((z - 1) / 2)\\nprint(number_of_dom)\\n\",\n \"try:\\n\\t(a, b) = map(int, input().split())\\n\\tprint(a * b // 2)\\nexcept:\\n\\tpass\\n\",\n \"inp = str(input())\\ninp = inp.split()\\ninp[0] = int(inp[0])\\ninp[1] = int(inp[1])\\narea = inp[0] * inp[1]\\nprint(area // 2)\\n\",\n \"class a:\\n\\n\\tdef get(k, m, n):\\n\\t\\tif not n % 2:\\n\\t\\t\\treturn m * (n // 2)\\n\\t\\telif m % 2 == 0 and n % 2 != 0:\\n\\t\\t\\treturn m // 2 * n\\n\\t\\telse:\\n\\t\\t\\treturn m * n // 2\\nb = a()\\n(m, n) = map(int, input().split())\\nprint(b.get(m, n))\\n\",\n \"import math\\n(l, w) = map(int, input().split())\\nif l % 2 == 0:\\n\\tprint(int(l * w / 2))\\nelse:\\n\\tl = l - 1\\n\\tm = int(l * w / 2)\\n\\tprint(m + math.floor(w / 2))\\n\",\n \"def floor(x: float) -> int:\\n\\n\\tdef abs(y: float) -> float:\\n\\t\\tif y < 0:\\n\\t\\t\\treturn y * -1\\n\\t\\telse:\\n\\t\\t\\treturn y\\n\\treturn int(x - abs(x - int(x)))\\n(M, N) = [int(x) for x in input().split()]\\nprint(floor(M * N / 2))\\n\",\n \"str1 = input()\\nlist1 = str1.split(' ')\\nn = int(int(list1[0]) * int(list1[1]) / 2)\\nprint(n)\\n\",\n \"(n, m) = [int(x) for x in input().split()]\\nc = int(n / 2)\\nrem = n % 2\\nc *= m\\nif rem == 0:\\n\\tprint(c)\\nelse:\\n\\tcount = int(m / 2)\\n\\tc += count\\n\\tprint(c)\\n\",\n \"from sys import stdin\\n\\ndef isSquare(n, m):\\n\\tif n % 2 == 0 and m % 2 == 0:\\n\\t\\treturn True\\n\\ndef count(n, m):\\n\\tif isSquare(n, m):\\n\\t\\treturn int(n * m / 2)\\n\\tif n == 1 and m != 1:\\n\\t\\treturn int(m / 2)\\n\\tif m == 1 and n != 1:\\n\\t\\treturn int(n / 2)\\n\\telif n % 2 == 0 and m % 2 != 0:\\n\\t\\treturn int(n * (m - 1) / 2 + n // 2)\\n\\telif n % 2 != 0 and m % 2 == 0:\\n\\t\\treturn int(m * (n - 1) / 2 + m // 2)\\n\\telif n % 2 != 0 and m % 2 != 0:\\n\\t\\treturn int((n - 1) * (m - 1) / 2 + n // 2 + (m - 1) // 2)\\narr = str(stdin.readline()).replace('\\\\n', '').split(' ')\\nprint(count(int(arr[0]), int(arr[1])))\\n\",\n \"(x, y) = [int(a) for a in input().split()]\\nk = x * y\\nl = k // 2\\nprint(l)\\n\",\n \"(n, m) = list(map(int, input().rstrip().split()))\\ntotal = m * n\\nprint(total // 2)\\n\",\n \"l = input()\\np = l.split()\\nm = int(p[0])\\nn = int(p[1])\\ns = m * n\\nans = int(s / 2)\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split(' '))\\na = m * n\\nif a % 2 == 1:\\n\\ta -= 1\\nprint(int(a / 2))\\n\",\n \"(m, n) = map(int, input().split(' '))\\nnumber_squares = m * n\\nif m > n:\\n\\tbigger_number = m\\n\\tsmaller_number = n\\nelse:\\n\\tbigger_number = n\\n\\tsmaller_number = m\\ndom = 0\\nif number_squares % 2 == 0:\\n\\tdom = bigger_number / 2 * smaller_number\\nelif number_squares % 2 == 1:\\n\\tfor i in range(1, bigger_number):\\n\\t\\tif (number_squares - i) % 2 == 0:\\n\\t\\t\\tdom = (number_squares - i) / 2\\n\\t\\tbreak\\nprint(int(dom))\\n\",\n \"import sys\\n(m, n) = map(int, sys.stdin.readline().split())\\nif m == 1 and n == 1:\\n\\tprint(0)\\n\\tsys.exit(0)\\ncount = m * n // 2\\nprint(count)\\n\",\n \"def no_of_dodo(x, y):\\n\\treturn int(int(x) * int(y) / 2)\\ninp = input().split()\\nans = no_of_dodo(inp[0], inp[1])\\nprint(ans)\\n\",\n \"def func():\\n\\tx = input().split()\\n\\tif int(x[1]) * int(x[0]) % 2 == 0:\\n\\t\\tprint(int(int(x[1]) * int(x[0]) / 2))\\n\\telse:\\n\\t\\tprint(int((int(x[1]) * int(x[0]) - 1) / 2))\\nfunc()\\n\",\n \"x = input()\\nf = ''\\np = 0\\nwhile p < len(x) and x[p] != ' ':\\n\\tf += x[p]\\n\\tp += 1\\nM = int(f)\\nN = int(x[len(f) + 1:len(x)])\\nif M % 2 != 0 and N % 2 != 0:\\n\\tres = (M * N - 1) // 2\\nelse:\\n\\tres = M * N // 2\\nprint(res)\\n\",\n \"num = input()\\nlist = num.split()\\nm = int(list[0])\\nn = int(list[1])\\nif m % 2 != 0 and n % 2 != 0:\\n\\tw = (m * n - 1) / 2\\nelse:\\n\\tw = m * n / 2\\nprint(int(w))\\n\",\n \"s = input()\\nl = s.split()\\na = int(l[0])\\nb = int(l[1])\\nprint(a * b // 2)\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nprint(math.ceil(m * n // 2))\\n\",\n \"Dominos = input()\\n(M, N) = Dominos.split(' ')\\nM = int(M)\\nN = int(N)\\n\\ndef MaxDom(L, W):\\n\\tDomL = L // 2\\n\\tDomW = W // 2\\n\\tDomNoL = 0\\n\\tDonNoW = 0\\n\\tOutput = 0\\n\\tif L % 2 == 0:\\n\\t\\tDomNoL = DomL * W\\n\\telif L % 2 > 0:\\n\\t\\tDomNoL = DomL * W + DomW\\n\\tif W % 2 == 0:\\n\\t\\tDomNoW = DomW * L\\n\\telif W % 2 > 0:\\n\\t\\tDomNoW = DomW * L + DomL\\n\\tif DomNoL > DomNoW:\\n\\t\\tOutput = DomNoL\\n\\t\\treturn Output\\n\\telif DomNoW > DomNoW:\\n\\t\\tOutput = DomNoW\\n\\t\\treturn Output\\n\\telif DomNoW == DomNoW:\\n\\t\\treturn DomNoW\\nprint(MaxDom(M, N))\\n\",\n \"import math\\n\\ndef main():\\n\\tnum = input()\\n\\tl = list(num.split(' '))\\n\\tM = int(l[0])\\n\\tN = int(l[1])\\n\\tsum = M * N\\n\\tprint(math.floor(sum / 2))\\nmain()\\n\",\n \"inputs = list(map(int, input().split(' ')))\\nM = inputs[0]\\nN = inputs[1]\\namount = N * M // 2\\nprint(str(amount))\\n\",\n \"(x, y) = tuple(input().split(' '))\\nx = int(x)\\ny = int(y)\\nw = int(y / 2)\\nsum = x * w\\nif x % 2 == 1:\\n\\tx -= 1\\nif y % 2 == 1:\\n\\tsum += x / 2\\nprint(int(sum))\\n\",\n \"(x, y) = [int(x) for x in input().split()]\\n(a, b) = (2, 1)\\nif x >= a or y >= b:\\n\\tc = x * y // 2\\n\\tprint(c)\\nelse:\\n\\tprint(0)\\n\",\n \"import sys\\nnumbers = sys.stdin.readlines()[0]\\n(m, n) = [int(x) for x in numbers.split(' ')]\\nif m % 2 == 0 or n % 2 == 0:\\n\\tprint(int(m * n / 2))\\nelse:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"w = input()\\nw = w.split()\\nw = list(w)\\nfor (i, elem) in enumerate(w):\\n\\tw[i] = int(elem)\\nm = w[0]\\nn = w[1]\\ns = m * n\\nif s % 2 == 0:\\n\\tprint(int(s / 2))\\nelse:\\n\\tprint(int((s - 1) / 2))\\n\",\n \"(n, m) = map(int, input().split())\\ns_rec = n * m\\ns_dom = 2 * 1\\nanswer = s_rec // s_dom\\nprint(answer)\\n\",\n \"import math\\n\\ndef main():\\n\\t(m, n) = list(map(int, input().split()))\\n\\tprint(int(math.floor(n * m * 0.5)))\\nmain()\\n\",\n \"(a, b) = input().split()\\nm = int(a)\\nn = int(b)\\nif m % 2 == 0:\\n\\tprint(str(m // 2 * n))\\nelse:\\n\\tprint(str(m // 2 * n + n // 2))\\n\",\n \"from sys import stdin, stdout\\n\\ndef read_int_input():\\n\\treturn map(int, stdin.readline().rstrip().split())\\n\\ndef read_str_input():\\n\\treturn stdin.readline().rstrip().split()\\n\\ndef write_output(result):\\n\\treturn stdout.write(str(result) + '\\\\n')\\n\\ndef main():\\n\\t(m, n) = read_int_input()\\n\\twrite_output(m * n // 2)\\nmain()\\n\",\n \"list = input().split()\\n(M, N) = map(int, list)\\nif M % 2 != 0 and N % 2 != 0:\\n\\ta = (M - 1) / 2\\n\\tb = N\\n\\tc = (N - 1) / 2\\n\\td = a * b + c\\n\\td = int(d)\\n\\tprint(d)\\nelse:\\n\\te = M * N / 2\\n\\te = int(e)\\n\\tprint(e)\\n\",\n \"n = input()\\nM = int(str(n).split()[0])\\nN = int(str(n).split()[1])\\narea = M * N\\nif area % 2 == 0:\\n\\tprint(int(area / 2))\\nelse:\\n\\tprint(int((area - 1) / 2))\\n\",\n \"from math import floor\\n(m, n) = map(int, input().split(' '))\\nboard_area = m * n\\ndomino_area = 2 * 1\\nans = floor(board_area / domino_area)\\nprint(ans)\\n\",\n \"nums = input().split(' ')\\nm = int(nums[0])\\nn = int(nums[1])\\ntotal = m * n\\nfit = int(total / 2)\\nprint(fit)\\n\",\n \"s = input().split(' ')\\nmul = int(s[0]) * int(s[1])\\nprint(mul // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nsq = m * n\\nrem = sq % 2\\nans = sq - rem\\nprint(ans // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nfrom math import *\\na = max(m, n)\\nb = min(m, n)\\np = a // 2 * b\\nif a % 2 != 0:\\n\\tp = p + b // 2\\n\\tprint(p)\\nelse:\\n\\tprint(p)\\n\",\n \"(m, n) = map(int, input().split())\\nt = m // 2 * n\\nif m % 2 == 1:\\n\\tt += n // 2\\nprint(t)\\n\",\n \"(m, n) = map(int, input().split())\\nsur = m * n\\ntiles = sur // 2\\nprint(tiles)\\n\",\n \"def test07():\\n\\t(m, n) = map(int, input().strip().split(' ')[0:2])\\n\\tif m * n % 2 == 0:\\n\\t\\tprint(int(m * n / 2))\\n\\telse:\\n\\t\\tprint(int((m * n - 1) / 2))\\ntest07()\\n\",\n \"def ans(a, b):\\n\\treturn a * b // 2\\n(n, k) = map(int, input().split(' '))\\nprint(ans(n, k))\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nif m % 2 == 1:\\n\\ty = int(m / 2) * n + int(n / 2)\\n\\tprint(int(y))\\nelse:\\n\\ty = int(m * n / 2)\\n\\tprint(y)\\n\",\n \"(a, b) = list(map(int, input().split()))\\nif a % 2 == 0:\\n\\tprint(a // 2 * b)\\nelif a % 2 != 0:\\n\\tt = a // 2 * b + b // 2\\n\\tprint(t)\\n\",\n \"key_input = input().split(' ')\\nprint(int(int(key_input[0]) * int(key_input[1]) / 2))\\n\",\n \"list1 = input().split()\\nm = int(list1[0])\\nn = int(list1[1])\\ndiv = n * m // 2\\nprint(div)\\n\",\n \"(m, n) = map(int, input().split())\\nM = m // 2\\na = m % 2\\nx = n * M\\nif a == 1:\\n\\tN = n // 2\\n\\tb = n % 2\\n\\tx = x + N\\nprint(x)\\n\",\n \"(m, n) = map(int, input().split())\\npd = m // 2\\nans = pd * n\\nif m % 2 == 1:\\n\\tsd = n // 2\\n\\tans += sd\\nprint(ans)\\n\",\n \"inputList = input().split()\\nvalues = [int(x) for x in inputList]\\nnumber = 0\\nif values[0] % 2 == 0 or values[1] % 2 == 0:\\n\\tif values[0] % 2 == 0 and values[1] % 2 == 0:\\n\\t\\tnumber = values[0] / 2 * values[1]\\n\\telif values[0] % 2 == 0 and values[1] % 2 == 1:\\n\\t\\tnumber = values[0] / 2 * values[1]\\n\\telif values[1] % 2 == 0 and values[0] % 2 == 1:\\n\\t\\tnumber = values[1] / 2 * values[0]\\nelse:\\n\\tnumber = (values[0] - 1) / 2 * values[1] + (values[1] - 1) / 2\\nprint(int(number))\\n\",\n \"def do(m, n):\\n\\tif m > n:\\n\\t\\t(m, n) = (n, m)\\n\\tans = 0\\n\\tif m % 2 == 0:\\n\\t\\tans = m // 2 * n\\n\\telse:\\n\\t\\tans = m // 2 * n + n // 2\\n\\tprint(ans)\\n(m, n) = map(int, input().split())\\ndo(m, n)\\n\",\n \"q = input().split()\\nM = int(q[0])\\nN = int(q[1])\\nif M % 2 == 0 and N % 2 == 0:\\n\\tt = M * N // 2\\nelif M % 2 == 0:\\n\\tt = M * (N - 1) // 2 + M // 2\\nelif N % 2 == 0:\\n\\tt = N * (M - 1) // 2 + N // 2\\nelse:\\n\\tt = (M - 1) * (N - 1) // 2 + M // 2 + N // 2\\nprint(t)\\n\",\n \"(panjang, lebar) = input().split()\\nprint(int(panjang) * int(lebar) // 2)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ndomino_size = 2 * 1\\nboard = m * n\\nsize = board // domino_size\\nprint(size)\\n\",\n \"import math\\n\\ndef main():\\n\\t(n, m) = [int(s) for s in input().split(' ')]\\n\\tl1 = n / 2\\n\\tw1 = m\\n\\tl2 = n\\n\\tw2 = m / 2\\n\\tprint(math.floor(max(l1 * w1, l2 * w2)))\\nmain()\\n\",\n \"import math\\n(n, m) = input().split(' ')\\nn = int(n)\\nm = int(m)\\nresult = n * m // 2\\nprint(result)\\n\",\n \"try:\\n\\t(m, n) = [int(i) for i in input().split(' ')]\\n\\tif m >= 1 and m >= 1 and (n >= m) and (m <= 16) and (n <= 16):\\n\\t\\tprint(int(m * n // 2))\\nexcept:\\n\\tpass\\n\",\n \"Dimensions = input().split()\\nfor measure in Dimensions:\\n\\ti = Dimensions.index(measure)\\n\\tDimensions[i] = float(measure)\\nprint(int(Dimensions[0] * Dimensions[1] / 2.0))\\n\",\n \"(M, N) = [int(i) for i in input().split(' ')]\\nresult = M * N / 2\\nprint(int(result))\\n\",\n \"import sys\\nimport math\\n(M, N) = map(int, sys.stdin.readline().split())\\nprint(math.floor(M * N / 2))\\n\",\n \"(a, c) = map(int, input().split(' '))\\ncount = 0\\ni = 0\\nl = max(a, c)\\nb = min(a, c)\\ni = 1\\nwhile b > 0:\\n\\tif b >= 2:\\n\\t\\tcount = l\\n\\t\\tcount = count * i\\n\\t\\tb -= 2\\n\\t\\ti += 1\\n\\telse:\\n\\t\\tm = l // 2\\n\\t\\tcount = count + m\\n\\t\\tb -= 1\\nprint(count)\\n\",\n \"l = input()\\n(n, m) = l.split()\\nn = int(n)\\nm = int(m)\\nprint(n * m // 2)\\n\",\n \"l = list(map(int, input().split()))\\n(m, n) = (l[0], l[1])\\nimport math\\nx = max(n, m)\\ny = min(n, m)\\nprint(int(math.floor(x * y / 2)))\\n\",\n \"import math\\n(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\na = M * N\\nres = math.trunc(a / 2)\\nprint(res)\\n\",\n \"a = input().split()\\n\\ndef f(l):\\n\\tb = [int(i) for i in l]\\n\\treturn b[0] * b[-1] // 2\\nprint(f(a))\\n\",\n \"def domin(input_user):\\n\\tn = input_user[0]\\n\\tm = input_user[1]\\n\\treturn int(m * n / 2)\\ninput_user = list(map(int, input().split()))\\nprint(domin(input_user))\\n\",\n \"(x, y) = map(int, input('').split())\\nresult = x * y\\nfinal = int(result / 2)\\nprint(final)\\n\",\n \"(first, second) = input().split(' ')\\nm = int(first)\\nn = int(second)\\nprint(int(m * n / 2))\\n\",\n \"l = input().split()\\na = int(l[0])\\nb = int(l[1])\\nc = a * b\\nif c % 2 == 0:\\n\\tk = c // 2\\nelse:\\n\\tk = int(c / 2)\\nprint(k)\\n\",\n \"def domino(rec):\\n\\ttot = rec // 2\\n\\treturn tot\\n(n, m) = map(int, input().strip().split(' '))\\nr = n * m\\nprint(domino(r))\\n\",\n \"x = input()\\ny = x.split(' ')\\njavab = 0\\nif int(y[0]) % 2 == 0:\\n\\tjavab = int(y[0]) // 2 * int(y[1])\\nelif int(y[1]) % 2 == 0:\\n\\tjavab = int(y[1]) // 2 * int(y[0])\\nelse:\\n\\tjavab = int(y[0]) // 2 * int(y[1]) + int(y[1]) // 2\\nprint(javab)\\n\",\n \"n = input()\\nl = n.split()\\nm = int(l[0])\\nn = int(l[1])\\nif 1 <= m <= 16 and 1 <= n <= 16:\\n\\ti = n * m / 2\\n\\tprint(int(i))\\n\",\n \"board = input().split()\\nM = int(board[0])\\nN = int(board[1])\\nnum = M * N\\nprint(num // 2)\\n\",\n \"from math import *\\n(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\nmulti = M * N\\ndivided_by = 2 * 1\\nif multi / divided_by == 0:\\n\\tprint(multi / divided_by)\\nelse:\\n\\tprint(floor(multi / divided_by))\\n\",\n \"(x, y) = map(int, input().split())\\na = int(x / 2)\\nb = int(y / 1)\\nprint(int(y * x / 2))\\n\",\n \"data = [int(x) for x in input().split()]\\nprint(int(data[0] * data[1] / 2))\\n\",\n \"l = [int(i) for i in input().split()]\\nl.sort()\\nlonger = l[1]\\nshorter = l[0]\\ns = 0\\nadditional = 0\\nrest = 0\\nif longer > 2:\\n\\tif shorter < 2:\\n\\t\\ts = shorter * int(longer / 2)\\n\\telse:\\n\\t\\ts = int(shorter / 2) * longer\\n\\t\\trest = shorter - 2 * int(shorter / 2)\\n\\t\\tadditional = int(longer / 2) * rest\\n\\t\\ts = s + additional\\nelif longer == 2:\\n\\ts = shorter\\nelse:\\n\\ts = 0\\nprint(s)\\n\",\n \"inp = input()\\n(m, n) = [int(x) for x in inp.split()]\\nprint(m * n // 2)\\n\",\n \"import math\\nx = input()\\nxx = x.split()\\nm = int(xx[0])\\nn = int(xx[1])\\nif n % 2 == 0:\\n\\tprint(int(n / 2 * m))\\nelse:\\n\\tprint(int(math.floor(n / 2) * m + math.floor(m / 2)))\\n\",\n \"razmery = input()\\nmassiv = razmery.split()\\nm = int(massiv[0])\\nn = int(massiv[1])\\ni = 2 * 1\\ns = m * n\\ndomino = s // i\\nprint(domino)\\n\",\n \"(length, width) = map(int, input().split())\\nnum = 0\\nif length >= 2:\\n\\tnum = length // 2 * width\\nif length % 2 == 1:\\n\\tnum = num + width // 2\\nprint(num)\\n\",\n \"(n, m) = list(map(lambda num: int(num), input().split(' ')))\\nprint(n * m // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nif 0 <= M <= N <= 16:\\n\\tif M % 2 == 0:\\n\\t\\tp = M / 2 * N\\n\\telif N % 2 == 0:\\n\\t\\tp = N / 2 * M\\n\\telse:\\n\\t\\tp = (N - 1) / 2 * M + (M - 1) / 2\\nprint(int(p))\\n\",\n \"import sys\\nimport math\\n\\ndef main():\\n\\tuser_input = input()\\n\\tuser_input = user_input.split()\\n\\tsize = int(user_input[0]) * int(user_input[1])\\n\\tprint(math.floor(size / 2))\\nmain()\\n\",\n \"s = input()\\n(nnn, mmm) = s.split()\\nn = int(nnn)\\nm = int(mmm)\\nsize = n * m\\nprint(size // 2)\\n\",\n \"(n, m) = tuple(map(int, input().split()))\\nz = int(n * m / 2)\\nprint(z)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\np = m * n\\nif p % 2 == 0:\\n\\tr = p / 2\\nelse:\\n\\tr = (p - 1) / 2\\nr = int(r)\\nprint(r)\\n\",\n \"(M, N) = list(map(int, input().split()))\\nSub = M * N\\nDominoes = Sub // 2\\nprint(Dominoes)\\n\",\n \"def domino(a, b):\\n\\tarea_domino = 2 * 1\\n\\tarea_board = a * b\\n\\treturn int(area_board / area_domino)\\n(a, b) = map(int, input().split())\\nprint(domino(a, b))\\n\",\n \"import math\\n(n, k) = input().split()\\nn = int(n)\\nk = int(k)\\nx = math.floor(n * k / 2)\\nprint(x)\\n\",\n \"(n, k) = map(int, input().split())\\nans = 0\\nwhile ans <= n * k:\\n\\tans += 2\\nans -= 2\\nprint(int(ans / 2))\\n\",\n \"dim = input()\\npos = dim.find(' ')\\nA = dim[0:pos]\\nB = dim[pos:]\\nC = int(A)\\nD = int(B)\\nmul = C * D\\ndiv = mul / 2\\nprint(int(div))\\n\",\n \"(x, y) = input().split()\\nm = int(x) * int(y) * 0.5\\nprint(int(m))\\n\",\n \"(a, b) = map(int, input().split())\\ns = a // 2 * b\\nif a % 2 != 0:\\n\\ts += b // 2\\nprint(s)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\nresult = 0\\nwhile n > 1:\\n\\tresult += m\\n\\tn -= 2\\nif n == 1:\\n\\tresult += m // 2\\nprint(result)\\n\",\n \"(chieuDai, chieuRong) = map(int, input().split())\\nsoDominoToiDa = int(chieuDai * chieuRong / 2)\\nprint(soDominoToiDa)\\n\",\n \"import math\\nMN = input()\\nMN = MN.split(' ')\\nM = int(MN[0])\\nN = int(MN[1])\\nif M % 2 == 0 and N % 2 == 0:\\n\\tprint(int(N * M / 2))\\nelse:\\n\\tprint(math.trunc(N * M / 2))\\n\",\n \"A = [int(x) for x in input().split()]\\nif A[0] * A[1] % 2 == 0:\\n\\ti = A[0] * A[1] / 2\\n\\tprint(str(int(i)))\\nelse:\\n\\tprint(str(int((A[0] * A[1] - 1) / 2)))\\n\",\n \"m_n = input()\\n(m, n) = m_n.split()\\n(m, n) = (int(m), int(n))\\nprint(m * n // 2)\\n\",\n \"(M, N) = input().split()\\nm = int(M)\\nn = int(N)\\nA = m * n\\nif A % 2 == 0:\\n\\tprint(int(A / 2))\\nelse:\\n\\tA - 1\\n\\tprint(int(A / 2))\\n\",\n \"def f(x, y):\\n\\treturn int(x * int(y / 2) + y % 2 * int(x / 2))\\n\\ndef main():\\n\\tl = input().split(' ')\\n\\tx = int(l[0])\\n\\ty = int(l[1])\\n\\tout = f(max(x, y), min(x, y))\\n\\tprint(out)\\nmain()\\n\",\n \"a = input().split()\\ny = [int(x) for x in a]\\nprod = 1\\nfor x in y:\\n\\tprod *= x\\nout = int(prod / 2)\\nprint(out)\\n\",\n \"(m_str, k_str) = input().split(' ')\\nm = int(m_str)\\nk = int(k_str)\\nif m * k % 2 == 0:\\n\\tprint(int(m * k / 2))\\nelse:\\n\\tprint(int((m * k - 1) / 2))\\n\",\n \"from math import floor\\nq = list(input().split(' '))\\nm = q[0]\\nn = q[1]\\nres = int(m) * int(n)\\nres = floor(res / 2)\\nprint(res)\\n\",\n \"import sys\\ninf = float('inf')\\nabc = 'abcdefghijklmnopqrstuvwxyz'\\nabd = {'a': 0, 'b': 1, 'c': 2, 'd': 3, 'e': 4, 'f': 5, 'g': 6, 'h': 7, 'i': 8, 'j': 9, 'k': 10, 'l': 11, 'm': 12, 'n': 13, 'o': 14, 'p': 15, 'q': 16, 'r': 17, 's': 18, 't': 19, 'u': 20, 'v': 21, 'w': 22, 'x': 23, 'y': 24, 'z': 25}\\n(mod, MOD) = (1000000007, 998244353)\\nvow = ['a', 'e', 'i', 'o', 'u']\\n(dx, dy) = ([-1, 1, 0, 0], [0, 0, 1, -1])\\n\\ndef get_array():\\n\\treturn list(map(int, sys.stdin.readline().strip().split()))\\n\\ndef get_ints():\\n\\treturn map(int, sys.stdin.readline().strip().split())\\n\\ndef input():\\n\\treturn sys.stdin.readline().strip()\\n(m, n) = get_ints()\\nmaxi = max(m, n)\\nmini = min(m, n)\\nans = m // 2 * n\\nif m & 1:\\n\\tans += n // 2\\nprint(ans)\\n\",\n \"(m, n) = map(int, input().split())\\nr = m // 2 * n\\nif m % 2 != 0:\\n\\tr += n // 2\\nprint(r)\\n\",\n \"input1 = [int(v) for v in input().split(' ')]\\ny = input1[0]\\nz = input1[1]\\nx = z * y\\nif x % 2 == 0:\\n\\tprint(x // 2)\\nelif x == 1:\\n\\tprint(0)\\nelse:\\n\\tfor i in range(x):\\n\\t\\tif (x - i) % 2 == 0:\\n\\t\\t\\tprint((x - i) // 2)\\n\\t\\t\\tbreak\\n\\t\\telse:\\n\\t\\t\\tcontinue\\n\",\n \"(a, b) = map(int, input().split())\\nc = a * b\\ne = c / 2\\nprint(int(e))\\n\",\n \"import math\\nsize = input().split()\\nprint(math.floor(int(size[0]) * int(size[1]) / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 == 0 or n % 2 == 0:\\n\\ti = m * n // 2\\n\\tprint(i)\\nelif m % 2 != 0 and n % 2 != 0:\\n\\tj = m * n // 2\\n\\tprint(j)\\nelif m % 2 == 0 and n % 2 == 0:\\n\\tk = m * n // 2\\n\\tprint(k)\\n\",\n \"(m, n) = map(int, input().split())\\nif m > 1:\\n\\tWidth = n\\n\\tHeight = m // 2\\n\\tExtra = 0\\n\\tif m % 2 != 0:\\n\\t\\tExtra = n // 2\\n\\tNumberOfDominoes = Width * Height + Extra\\nelse:\\n\\tNumberOfDominoes = n // 2\\nprint(NumberOfDominoes)\\n\",\n \"(n, m) = map(int, input().split())\\ns = 2 * 1\\nc = 0\\nwhile n * m >= s:\\n\\ts += 2\\n\\tc += 1\\nprint(c)\\n\",\n \"s = input()\\ns = s.split(' ')\\n(x, y) = (int(s[0]), int(s[1]))\\nprint(x * y >> 1)\\n\",\n \"(M, N) = map(int, input().split(' '))\\nmulit = M * N\\nde = mulit // 2\\nprint(de)\\n\",\n \"(n, k) = map(int, input().strip().split(' '))\\narea = n * k\\nprint(area // 2)\\n\",\n \"(n, k) = map(int, input().split(' '))\\nd = 2 * 1\\nf = n * k // d\\nprint(f)\\n\",\n \"astr = input().split()\\n(m, n) = (int(astr[0]), int(astr[1]))\\nproduct = m * n\\nprint(product // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nprint(max(m // 2 * n // 1, m // 1 * n // 2))\\n\",\n \"a = input()\\n(m, n) = a.split(' ')\\nm = int(m)\\nn = int(n)\\nif m >= 1 and n >= m:\\n\\tif n <= 16:\\n\\t\\tres = m * n // 2\\n\\t\\tprint(res)\\n\",\n \"import sys\\ndata = list(map(int, sys.stdin.read().split()))\\nprint(data[0] * data[1] // 2)\\n\",\n \"inputDimension = input().split(' ')\\ntotalDimension = int(inputDimension[0]) * int(inputDimension[1])\\nprint(int(totalDimension / 2))\\n\",\n \"list = [int(i) for i in input().split()]\\nn = list[0] * list[1] // 2\\nprint(n)\\n\",\n \"from math import *\\n(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nz = x * y // 2\\nprint(z)\\n\",\n \"while True:\\n\\t(m, n) = map(int, input().split(' '))\\n\\tif 1 > m > n > 16:\\n\\t\\tprint('please provide a number between 1 and 16')\\n\\t\\tbreak\\n\\tbreak\\narea_of_rectangle = m * n\\narea_of_domino = 2\\nif area_of_rectangle >= area_of_domino:\\n\\tprint(int(area_of_rectangle / area_of_domino))\\nelse:\\n\\tprint(0)\\n\",\n \"from sys import stdin\\n\\ndef readInts():\\n\\treturn map(int, stdin.readline().strip().split())\\n\\ndef solve(m, n):\\n\\tout = m * n // 2\\n\\treturn out\\n\\ndef run():\\n\\t(m, n) = readInts()\\n\\tprint(solve(m, n))\\nrun()\\n\",\n \"a = [int(x) for x in input().split(' ')]\\nfor num in a:\\n\\tif num % 2 != 0:\\n\\t\\tnum -= 1\\nprint(int(a[0] * a[1] / 2))\\n\",\n \"(M, N) = map(int, input().split())\\nl = M * N\\nm = l // 2\\nprint(m)\\n\",\n \"(m, n) = [int(e) for e in input().split()]\\nprint(m * n // 2)\\n\",\n \"import re\\nboard = input()\\nsetq = re.compile('\\\\\\\\d{2}|\\\\\\\\d')\\nnums = setq.findall(board)\\nm = int(nums[0])\\nn = int(nums[1])\\nif m == 1 and n % 2 == 0:\\n\\tprint(int(n / 2))\\nelif m == 1 and n % 2 == 1:\\n\\tprint(int((n - 1) / 2))\\nelif m % 2 and n % 2 == 1:\\n\\tprint(int((m - 1) / 2 * n + (n - 1) / 2))\\nelif m % 2 == 0 and n % 2 == 0:\\n\\tprint(int(m / 2 * n))\\nelif m % 2 == 0 and n % 2 == 1:\\n\\tprint(int(m / 2 * n))\\nelif m % 2 == 1 and n % 2 == 0:\\n\\tprint(int((m - 1) / 2 * n + n / 2))\\n\",\n \"inp_data = input()\\nparsed_data = list(inp_data.split(' '))\\ns_field = int(parsed_data[0]) * int(parsed_data[1])\\nprint(s_field // 2)\\n\",\n \"def parser():\\n\\twhile 1:\\n\\t\\tdata = list(input().split(' '))\\n\\t\\tfor number in data:\\n\\t\\t\\tif len(number) > 0:\\n\\t\\t\\t\\tyield number\\ninput_parser = parser()\\n\\ndef get_word():\\n\\tglobal input_parser\\n\\treturn next(input_parser)\\n\\ndef get_number():\\n\\tdata = get_word()\\n\\ttry:\\n\\t\\treturn int(data)\\n\\texcept ValueError:\\n\\t\\treturn float(data)\\nimport math\\nM = get_number()\\nN = get_number()\\nif M % 2 == 1 and N % 2 == 1:\\n\\tanswer = (M * N - 1) / 2\\nelse:\\n\\tanswer = M * N / 2\\nprint(int(answer))\\n\",\n \"x = input().split()\\nm = int(x[0])\\nn = int(x[1])\\nif m % 2 == 0:\\n\\ta = m / 2\\n\\tprint(int(a * n))\\nif m % 2 != 0 and n % 2 == 0:\\n\\ta = int(m / 2)\\n\\tprint(int(a * n + n / 2))\\nif m % 2 != 0 and n % 2 != 0:\\n\\ta = int(m / 2)\\n\\tb = int(n / 2)\\n\\tprint(int(a * n + b))\\n\",\n \"(l, w) = map(int, input().split(' '))\\narea = l * w\\nprint(int(area / 2))\\n\",\n \"inp = [int(i) for i in input('').split(' ')]\\nres = inp[0] * inp[1] // 2\\nprint(res)\\n\",\n \"import math\\nline = input()\\nargs = line.split(' ')\\nm = int(args[0])\\nn = int(args[1])\\ns = m * n\\nt = math.floor(s / 2)\\nprint(t)\\n\",\n \"values = input().split()\\nside1 = int(values[0])\\nside2 = int(values[1])\\ndomino = 2\\nsum_of_sides = side1 * side2\\nitogo = sum_of_sides // domino\\nprint(itogo)\\n\",\n \"(n, m) = map(int, input().split())\\ns = n * m\\nr = s // 2\\nprint(r)\\n\",\n \"l = list(map(int, input().split()))\\narea = l[0] * l[1]\\nprint(area // 2)\\n\",\n \"sides = [int(el) for el in input().split(' ')]\\nprint(sides[0] * sides[1] // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nrec = m * n\\ndom = 2\\nprint(rec // dom)\\n\",\n \"X = input().split()\\nM = int(X[0])\\nN = int(X[1])\\nprint(M * N // 2)\\n\",\n \"input_arr = [int(i) for i in input().split()]\\nm = input_arr[0]\\nn = input_arr[1]\\nm1 = m % 2\\nn1 = n % 2\\nm2 = m // 2\\nn2 = n // 2\\nans = m2 * n2 * 2 + (0 if m1 == 0 else n2) + (0 if n1 == 0 else m2)\\nprint(ans)\\n\",\n \"import math\\ndata = input()\\n(M, N) = [int(x) for x in data.split()]\\nboardSquares = M * N\\nprint(math.floor(M * N / 2))\\n\",\n \"def solve(m, n):\\n\\tta = 2 * 1\\n\\tba = m * n\\n\\treturn ba // ta\\n(m, n) = map(int, input().split(' '))\\nprint(solve(m, n))\\n\",\n \"nums = input().split()\\n(m, n) = (int(nums[0]), int(nums[1]))\\nif m % 2 == 0:\\n\\tnum = int(m / 2) * n\\nelse:\\n\\tnum = int(m / 2) * n + int(n / 2)\\nprint(num)\\n\",\n \"array = input()\\narray = array.split()\\narray = [int(i) for i in array]\\noutput = int(array[0] * array[1] // 2)\\nprint(output)\\n\",\n \"import os\\nimport sys\\n(n, m) = map(int, input().split(' '))\\nif m > n:\\n\\t(n, m) = (m, n)\\nans = int(n / 2) * m\\nif n % 2 == 1:\\n\\tans += int(m / 2)\\nprint(ans)\\n\",\n \"numeros = input()\\nnumeros = numeros.split()\\nM = int(numeros[0])\\nN = int(numeros[1])\\nTotal = 0\\nif 1 <= M and M <= N and (N <= 16):\\n\\tTotal = M // 2 * N\\nif M % 2 == 0:\\n\\tTotal = Total\\nelse:\\n\\tTotal = Total + N // 2\\nprint(Total)\\n\",\n \"s = input()\\nline = s.split()\\nline = [int(e) for e in line]\\narea = line[0] * line[1]\\nprint(area // 2)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\ndomin = m * n // 2\\nprint(domin)\\n\",\n \"(a, b) = (int(x) for x in input().split(' '))\\nc = int(a)\\nd = int(b)\\nn = c // 2\\nsum = n * b\\nif c % 2 == 1:\\n\\tsum += d // 2\\nprint(sum)\\n\",\n \"line = input()\\n(m, n) = line.split()\\n(m, n) = (int(m), int(n))\\nresult = n * m // 2\\nprint(result)\\n\",\n \"def go():\\n\\t(n, m) = [int(i) for i in input().split(' ')]\\n\\ttotal = 0\\n\\tif n % 2 == 0:\\n\\t\\ttotal += n // 2 * m\\n\\telif m % 2 == 0:\\n\\t\\ttotal += m // 2 * n\\n\\telse:\\n\\t\\ttotal += n // 2 * m + m // 2\\n\\treturn total\\nprint(go())\\n\",\n \"(m, n) = map(int, input().split())\\nif m == 0 and n == 0:\\n\\tprint(0)\\ns = m * n\\ndominos = s // 2\\nprint(dominos)\\n\",\n \"zeile1 = input('')\\nwertezeile1 = []\\nzahl = ''\\nfor i in range(len(zeile1)):\\n\\tif zeile1[i] != ' ':\\n\\t\\tzahl = zahl + zeile1[i]\\n\\telse:\\n\\t\\twertezeile1.append(int(zahl))\\n\\t\\tzahl = ''\\n\\tif i == len(zeile1) - 1:\\n\\t\\twertezeile1.append(int(zahl))\\n\\t\\tzahl = ''\\ngroesex = wertezeile1[0]\\ngroesey = wertezeile1[1]\\nif groesex * groesey % 2 == 0:\\n\\tergebnis = groesex * groesey / 2\\nelse:\\n\\tergebnis = (groesex * groesey - 1) / 2\\nprint(int(ergebnis))\\n\",\n \"from sys import stdin, stdout, setrecursionlimit\\nimport math\\n\\ndef get_int():\\n\\treturn int(stdin.readline().strip())\\n\\ndef get_ints():\\n\\treturn map(int, stdin.readline().strip().split())\\n\\ndef get_string():\\n\\treturn stdin.readline().strip()\\n\\ndef get_list():\\n\\treturn list(map(int, stdin.readline().strip().split()))\\n(m, n) = get_ints()\\nstdout.write(str(math.floor(n * m / 2)))\\n\",\n \"(M, N) = map(int, input().split(' '))\\nq = M * N // 2\\nprint(q)\\n\",\n \"import math\\nlst = list(map(int, input().rstrip().split()))\\nm = int(lst[0])\\nn = int(lst[1])\\nx1 = m * n\\nx2 = int(x1 / 2)\\nprint(x2)\\n\",\n \"from sys import stdin, stdout\\n\\ndef main():\\n\\tip = stdin.readline().split()\\n\\tm = int(ip[0])\\n\\tn = int(ip[1])\\n\\tstdout.write(str(m * n // 2))\\nmain()\\n\",\n \"import math\\n(m, n) = map(int, input().split(' '))\\na = 2\\nb = 1\\ns1 = a * b\\ns2 = m * n\\ni = s2 / s1\\nprint(int(math.floor(i)))\\n\",\n \"(m, n) = map(int, input().split())\\ntotal_area = m * n\\ndominoes = int(total_area / 2)\\nprint(dominoes)\\n\",\n \"def domino(a, b):\\n\\tsum = 0\\n\\tsum += a * (b // 2)\\n\\tif b % 2 == 1:\\n\\t\\tsum += a // 2\\n\\treturn sum\\n(a, b) = map(int, input().split())\\nprint(domino(a, b))\\n\",\n \"from sys import stdin\\n(m, n) = map(int, stdin.read().split())\\nprint(m * n // 2)\\n\",\n \"dist = input()\\ndist = dist.split()\\nN = int(dist[0])\\nM = int(dist[1])\\nA = N * M\\nr = A // 2\\nprint(r)\\n\",\n \"import sys\\nif sys.version_info.major < 3:\\n\\tinput = raw_input\\n\\ndef main():\\n\\t(m, n) = map(int, input().split())\\n\\treturn m * n // 2\\nprint(main())\\n\",\n \"nums = input()\\n(n, m) = nums.split()\\nmult = int(n) * int(m)\\nif mult % 2 == 0:\\n\\tres = mult / 2\\nelse:\\n\\tres = (mult - 1) / 2\\nprint(int(res))\\n\",\n \"def domino(a, b):\\n\\tif a * b < 2:\\n\\t\\treturn 0\\n\\telif a == 1:\\n\\t\\treturn int(b / 2)\\n\\telif b == 1:\\n\\t\\treturn int(a / 2)\\n\\telse:\\n\\t\\tresult = a * int(b / 2)\\n\\t\\tif b % 2 != 0:\\n\\t\\t\\tresult += int(a / 2)\\n\\t\\treturn result\\nx = input()\\n(a, b) = x.split()\\n(a, b) = (int(a), int(b))\\nprint(domino(a, b))\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\narea_of_board = m * n\\narea_of_domino = 2\\nno_of_domino = int(area_of_board / 2)\\nverify = type(no_of_domino)\\nif verify == float:\\n\\tprint(round(no_of_domino) - 1)\\nelif verify == int:\\n\\tprint(round(no_of_domino))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\narea = m * n\\nif area % 2 == 1:\\n\\tarea = area - 1\\nprint(area // 2)\\n\",\n \"(m, n) = map(int, input().split())\\nx = 2\\ny = m * n\\nz = y // x\\nprint(z)\\n\",\n \"(m, n) = map(int, input().split())\\nx = m * n\\nif x < 2:\\n\\tprint('0')\\nelif x == 2:\\n\\tprint('1')\\nelse:\\n\\ta = m // 2\\n\\tb = m % 2\\n\\tc = n // 2\\n\\tif b == 0:\\n\\t\\tprint(n * a)\\n\\telse:\\n\\t\\tprint(n * a + c)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nda = 2\\nba = m * n\\nprint(int(ba / da))\\n\",\n \"import sys\\nnumbers = sys.stdin.readline()\\nm = int(numbers.split(' ')[0])\\nn = int(numbers.split(' ')[1])\\nspaces = n * m\\nmn = int(spaces / 2)\\nprint(mn)\\n\",\n \"(a, b) = map(int, input().split())\\nprint('{0}'.format(a * b // 2))\\n\",\n \"(l, b) = map(int, input().split())\\narea = l * b\\nprint(area // 2)\\n\",\n \"def main():\\n\\t(m, n) = ints_from_input()\\n\\tresult = 0\\n\\tif m / 2 > 0:\\n\\t\\tresult += m // 2 * n\\n\\tif m % 2:\\n\\t\\tresult += n // 2\\n\\treturn result\\n\\ndef ints_from_input():\\n\\treturn [int(i) for i in input().split()]\\nprint(main())\\n\",\n \"tablero = input()\\ntablero2 = [int(i) for i in tablero.split(' ')]\\narea = tablero2[0] * tablero2[1]\\nresultado = area // 2\\nprint(resultado)\\n\",\n \"try:\\n\\t(m, n) = map(int, input().split())\\n\\tprint(m * n // 2)\\n\\tpass\\nexcept Exception:\\n\\tpass\\n\",\n \"try:\\n\\tprint(eval('*'.join(input().split())) // 2)\\nexcept:\\n\\tpass\\n\",\n \"board = [int(a) for a in input().split(' ')]\\nprint(board[0] * board[1] // 2)\\n\",\n \"(M, N) = map(int, input().split())\\nndominos = M // 2 * N\\nif M % 2 == 1:\\n\\tndominos += N // 2\\nprint(ndominos)\\n\",\n \"(m, n) = map(int, input().split(' '))\\nsum = 0\\nsum += n * m // 2\\nprint(sum)\\n\",\n \"import string\\narr = list(map(int, input().split()))\\nn = arr[0]\\nm = arr[1]\\nnumberOfSquares = n * m\\nnumberOfDominos = numberOfSquares // 2\\nprint(numberOfDominos)\\n\",\n \"x = str(input())\\nn = str(x[-2:])\\nm = str(x[:2])\\nn = int(n)\\nm = int(m)\\nw = n * m\\nj = int(w / 2)\\nprint(j)\\n\",\n \"raw_str = input().split()\\nM = int(raw_str[0])\\nN = int(raw_str[1])\\nmatrix = [[0 for x in range(N)] for y in range(M)]\\ncount = 0\\nfor i in range(0, M):\\n\\tfor j in range(0, N):\\n\\t\\tif matrix[i][j] == 0:\\n\\t\\t\\tif i + 1 != M and matrix[i + 1][j] == 0:\\n\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\tmatrix[i + 1][j] = 1\\n\\t\\t\\t\\tcount += 1\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\tif i - 1 != -1 and matrix[i - 1][j] == 0:\\n\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\tmatrix[i - 1][j] = 1\\n\\t\\t\\t\\tcount += 1\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\tif j + 1 != N and matrix[i][j + 1] == 0:\\n\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\tmatrix[i][j + 1] = 1\\n\\t\\t\\t\\tcount += 1\\n\\t\\t\\t\\tcontinue\\n\\t\\t\\tif j - 1 != -1 and matrix[i][j - 1] == 0:\\n\\t\\t\\t\\tmatrix[i][j] = 1\\n\\t\\t\\t\\tmatrix[i][j - 1] = 1\\n\\t\\t\\t\\tcount += 1\\n\\t\\t\\t\\tcontinue\\nprint(count)\\n\",\n \"(n, m) = input().split()\\nn = int(n)\\nm = int(m)\\nres = 0\\nflag = 0\\nif m % 2 == 0:\\n\\tres = int(m / 2)\\n\\tres = res * n\\nelse:\\n\\tres = int(m / 2)\\n\\tres = res * n\\n\\tres += int(n / 2)\\nprint(res)\\n\",\n \"(m, n) = map(int, input().split())\\npoN = 0\\npoM = 0\\nif n % 2 != 0:\\n\\tprint(m // 2 + n // 2 * m)\\nelse:\\n\\tprint(n // 2 * m)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nt = 2\\nb = m * n\\nprint(b // t)\\n\",\n \"import math\\n(m, n) = map(int, input().split())\\nmul = m * n\\ndiv = mul / 2\\nres = math.floor(div)\\nprint(res)\\n\",\n \"MN = input().split(' ')\\ncol = int(MN[0])\\nrow = int(MN[1])\\ntbo = [1, 1]\\nboard = []\\nfor _ in range(row):\\n\\tc = []\\n\\tfor _ in range(col):\\n\\t\\tc.append(0)\\n\\tboard.append(c)\\nif row % 2 == 0:\\n\\tx = row / 2\\n\\tpiles = x * col\\nelif col % 2 == 0:\\n\\tx = col / 2\\n\\tpiles = x * row\\nelif col % 2 != 0 and row % 2 != 0:\\n\\ty1 = col - 1\\n\\tx1 = y1 / 2 * row\\n\\ty2 = row - 1\\n\\tx2 = y2 / 2\\n\\tpiles = x1 + x2\\nprint(round(piles))\\n\",\n \"l = input().split()\\nif int(l[0]) == 1 and int(l[1]) == 1:\\n\\tprint('0')\\nelif int(l[0]) % 2 == 0 or int(l[1]) % 2 == 0:\\n\\tprint(str(int(int(l[0]) * int(l[1]) / 2)))\\nelse:\\n\\tprint(str(int((int(l[0]) * int(l[1]) - 1) / 2)))\\n\",\n \"i = list(map(int, input().split()))\\nm = i[0]\\nn = i[1]\\nx = m * n\\nprint(x // 2)\\n\",\n \"line = input()\\ntemp = line.split()\\nm = int(temp[0])\\nn = int(temp[1])\\nif m == 1:\\n\\tprint(int(n // 2))\\nif m == 2:\\n\\tprint(n)\\nans = 0\\nif m > 2:\\n\\tans += m // 2 * n\\n\\tif m % 2 == 1:\\n\\t\\tans += n // 2\\n\\tprint(ans)\\n\",\n \"from math import floor\\n(m, n) = input('').split(' ')\\n(m, n) = (int(m), int(n))\\narea = m * n\\nnDominoes = floor(area / 2)\\nprint(nDominoes)\\n\",\n \"(m, n) = map(int, input().split())\\nar = m * n\\nnm = ar // 2\\nprint(nm)\\n\",\n \"MN = input().split(' ')\\nm = int(MN[0])\\nn = int(MN[1])\\nproduct = m * n\\nblocks = product // 2\\nprint(blocks)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ni = 0\\nj = 0\\nwhile m > 1:\\n\\ti = i + n\\n\\tm = m - 2\\n\\tif m <= 1:\\n\\t\\tbreak\\nwhile n >= 2 and m >= 1:\\n\\tj += 1\\n\\tn = n - 2\\n\\tif n < 2:\\n\\t\\tbreak\\nk = i + j * m\\nprint(k)\\n\",\n \"k = 1\\nn = input()\\nn = n.split()\\nfor i in n:\\n\\tk = int(i) * int(k)\\nprint(k // 2)\\n\",\n \"from math import *\\n(m, n) = input().split()\\nareamn = int(m) * int(n)\\nans = floor(areamn / 2)\\nprint(ans)\\n\",\n \"dat = input()\\nlqw = dat.split(' ')\\nlol = []\\nfor i in lqw:\\n\\tlol.append(int(i))\\nprint(lol[0] * lol[1] // 2)\\n\",\n \"arr = input().split()\\nm = int(arr[0])\\nn = int(arr[1])\\nprint(m * n // 2)\\n\",\n \"T = str(input()).split(' ')\\nM = int(T[0])\\nN = int(T[1])\\nnumberofdomino = 0\\nif M >= 1 and M <= N:\\n\\tif N >= M and N <= 16:\\n\\t\\tareaofboard = M * N\\n\\t\\tnumberofdomino = areaofboard / 2\\n\\t\\tnumberofdomino = int(str(numberofdomino).split('.')[0])\\nprint(numberofdomino)\\n\",\n \"(n, m) = list(map(int, input().split()))\\nc = n * m\\nprint(c // 2)\\n\",\n \"a = input()\\nlist_1 = a.split()\\nm = int(list_1[0])\\nn = int(list_1[1])\\no = int(m * n / 2)\\nprint(o)\\n\",\n \"import sys\\nimport math\\nfrom operator import mul\\n(a, b) = map(int, sys.stdin.readline().split())\\nprint(math.floor(int(a) * int(b) / 2))\\n\",\n \"import math\\n(M, N) = map(int, input().split())\\nprint(str(math.floor(M * N / 2)))\\n\",\n \"(x, y) = map(int, input().split())\\nd = 0\\n\\ndef domino(x, y):\\n\\treturn int(x / 2) * y\\nif x % 2 == 0:\\n\\td = domino(x, y)\\nelse:\\n\\td = domino(x, y)\\n\\td += domino(y, 1)\\nprint(d)\\n\",\n \"(M, N) = input().split()\\nM = int(M)\\nN = int(N)\\na = M * N\\nx = M // 2\\ny = N // 2\\ns = x * y\\na1 = s * 2\\na2 = a - a1\\nr = a2 // 2\\nf = s + r\\nprint(f)\\n\",\n \"l = input().split(' ')\\nrows = int(l[0])\\ncols = int(l[1])\\nres = rows // 2 * cols\\nif rows % 2 != 0:\\n\\tres += cols // 2\\nprint(res)\\n\",\n \"(a, b) = map(int, input().split())\\nz = 0\\nz = a * b // 2\\nprint(z)\\n\",\n \"numbers = input()\\n(M, N) = numbers.split(' ')\\nm = eval(M)\\nn = eval(N)\\nsize = m * n\\nresult = size // 2\\nprint(result)\\n\",\n \"(n, m) = list(map(int, input().split()))\\na = 2 * 1\\nsum = n * m\\nprint(sum // a)\\n\",\n \"(m, n) = map(int, input().split())\\nfinal = 0\\narea = m * n\\nif area >= 2:\\n\\tfinal = area // 2\\nprint(final)\\n\",\n \"NM = list(map(int, input().split()))\\nprint(NM[0] * NM[1] // 2)\\n\",\n \"M_and_N = input()\\nM_and_N = M_and_N.split(' ')\\nM = int(M_and_N[0])\\nN = int(M_and_N[1])\\nif M % 2 == 0:\\n\\tnum = M // 2 * N\\nelse:\\n\\tnum = M // 2 * N + N // 2\\nprint(num)\\n\",\n \"num = input().split(' ')\\nfor i in range(len(num)):\\n\\tnum[i] = int(num[i])\\nm = num[0]\\nn = num[1]\\nprint(m * n // 2)\\n\",\n \"import math\\n(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\na = m * n\\nans = a / 2\\nval = math.floor(ans)\\nprint(val)\\n\",\n \"(M, N) = map(int, input().split())\\na = 2\\ns = M % a\\nif s == 0:\\n\\tprint(M // a * N)\\nif s != 0:\\n\\tm = N // 2\\n\\ttotal = M // a * N + m\\n\\tprint(total)\\n\",\n \"(m, n) = map(int, input().split())\\na = m * n\\nfinal = a // 2\\nprint(final)\\n\",\n \"(n, k) = map(int, input().split())\\nh = min(n, k)\\nw = max(n, k)\\nres = h * (w // 2)\\nif w % 2 != 0:\\n\\tres += h // 2\\nprint(res)\\n\",\n \"A = input().split(' ')\\nB = [int(elem) for elem in A]\\n(n, m) = (B[0], B[1])\\nprint(int(n * m / 2))\\n\",\n \"(m, n) = map(int, input().split())\\nk = 0\\nk = m * n // 2\\nprint(k)\\n\",\n \"(a, b) = input().split()\\n(a, b) = (int(a), int(b))\\nx = a * b\\nif x % 2 == 1:\\n\\tx -= 1\\nx /= 2\\nprint(int(x))\\n\",\n \"def domino():\\n\\t(n, m) = map(int, input().split())\\n\\tx = n * m\\n\\tdom = 0\\n\\tif x % 2 == 0:\\n\\t\\tdom = int(x / 2)\\n\\telse:\\n\\t\\tdom = int((x - 1) / 2)\\n\\tprint(dom)\\ndomino()\\n\",\n \"import math\\ninputNums = input()\\nq = []\\nfor i in inputNums.split(' '):\\n\\tq.append(i)\\nm = int(q[0])\\nn = int(q[1])\\nprint(math.floor(m * n / 2))\\n\",\n \"(l, w) = map(int, input().split())\\narea = l * w\\ndominoes = area // 2\\nprint(str(dominoes))\\n\",\n \"def inp_m_n():\\n\\tm_n = input()\\n\\tm_n = list(m_n.split(' '))\\n\\tm_n = list(map(int, m_n))\\n\\treturn m_n\\nm_n = inp_m_n()\\nm = m_n[0]\\nn = m_n[1]\\nN = m * n // 2\\nprint(N)\\n\",\n \"(m, n) = map(int, input().split())\\nd = 0\\ns = m * n\\nprint(int(s / 2))\\n\",\n \"from math import floor\\n\\ndef main():\\n\\trdl = input().split()\\n\\tn = int(rdl[0])\\n\\tm = int(rdl[1])\\n\\ts = n * m\\n\\tprint(floor(s / 2))\\nmain()\\n\",\n \"t = [int(x) for x in input().split()]\\nres = 0\\nif t[0] > 1 and t[1] > 1:\\n\\tif t[0] % 2 == 0:\\n\\t\\tres = int(t[0] / 2 * t[1])\\n\\telif t[1] % 2 == 0:\\n\\t\\tres = int(t[1] / 2 * t[0])\\n\\telse:\\n\\t\\tres = int(t[0] / 2) * t[1] + int(t[1] / 2)\\nelse:\\n\\tt.sort()\\n\\tres = int(t[1] / 2)\\nprint(res)\\n\",\n \"(rec1, rec2) = input().split()\\na = int(rec1) * int(rec2)\\nprint(a // 2)\\n\",\n \"def domino(M, N):\\n\\tif M != 1 and N != 1 and (M != 0) and (N != 0):\\n\\t\\treturn M + N - 2 + domino(M - 2, N - 2)\\n\\telif M == 1 or N == 1:\\n\\t\\tif N == 1:\\n\\t\\t\\treturn M // 2\\n\\t\\telse:\\n\\t\\t\\treturn N // 2\\n\\telse:\\n\\t\\treturn 0\\n(M, N) = list(map(int, input().strip().split()))\\nprint(domino(M, N))\\n\",\n \"(k, n) = [int(s) for s in input().split()]\\nprint(k * n // 2)\\n\",\n \"from sys import stdin\\n\\ndef main():\\n\\tn = [int(x) for x in stdin.readline().strip().split()]\\n\\tx = n[0]\\n\\ty = n[1]\\n\\tprint(x * y // 2)\\nmain()\\n\",\n \"(m, n) = map(int, input().split())\\nfield_area = m * n\\ndomino_area = 2 * 1\\nprint(field_area // domino_area)\\n\",\n \"import sys\\n\\ndef get_ints():\\n\\treturn map(int, sys.stdin.readline().strip().split())\\n(m, n) = get_ints()\\nprint(int(m * n / 2))\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\narea = a * b\\narea_of_domino = 2\\nprint(area // area_of_domino)\\n\",\n \"import math\\nmn = list(map(int, input().strip().split()))\\n(r1, r2, c1, c2) = (0, 0, 0, 0)\\nr1 = math.floor(mn[0] / 2)\\nc1 = math.floor(mn[1] / 1)\\nif mn[0] % 2 == 0:\\n\\tmn[0] = 0\\nelse:\\n\\tmn[0] -= 2 * r1\\nr2 = math.floor(mn[0] / 1)\\nc2 = math.floor(mn[1] / 2)\\nprint(r1 * c1 + r2 * c2)\\n\",\n \"n = list(map(int, input().split()))\\nmul = n[0] * n[1]\\nprint(mul // 2)\\n\",\n \"(row_size, col_size) = map(int, input().split())\\nsquares = row_size * col_size\\nprint(squares // 2)\\n\",\n \"a = input().split()\\nn = int(max(a[0], a[1]))\\nm = int(min(a[0], a[1]))\\nif n % 2 != 0:\\n\\tx = n // 2 * m + m // 2\\nelse:\\n\\tx = n // 2 * m\\nprint(x)\\n\",\n \"(M, N) = input().split(' ')\\nN = int(N)\\nM = int(M)\\nx = 0\\nwhile N > 1:\\n\\tx = M + x\\n\\tN = N - 2\\nwhile M > 1 and N != 0:\\n\\tx = x + 1\\n\\tM = M - 2\\nprint(x)\\n\",\n \"try:\\n\\t(m, n) = input().split(' ')\\n\\tif int(m) >= 1 and int(m) <= 16 and (int(m) >= 1) and (int(m) <= 16):\\n\\t\\ttotal = int(m) * int(n)\\n\\t\\tnumber_of_puzzles = total // 2\\n\\t\\tprint(number_of_puzzles)\\nexcept Exception as e:\\n\\tprint(e)\\n\",\n \"(m, n) = map(int, input().split())\\nif m < 2 and n < 2:\\n\\tprint(0)\\nelse:\\n\\tq1 = m // 2\\n\\tq2 = m % 2\\n\\tprint(q1 * n + q2 * n // 2)\\n\",\n \"dom = input().split()\\nres = int(int(dom[0]) * int(dom[1]) / 2)\\nprint(res)\\n\",\n \"s = input().split(' ')\\nfor hj in range(len(s)):\\n\\ts[hj] = int(s[hj])\\nprint(int(s[0] * s[1] // 2))\\n\",\n \"import math\\nstdin = input()\\ndim = stdin.split(' ')\\nm = int(dim[0])\\nn = int(dim[1])\\nsolution = math.floor(m * n * 0.5)\\nprint(solution)\\n\",\n \"def Convert(string):\\n\\tli = list(string.split(' '))\\n\\treturn li\\ndim = input()\\nlisto = Convert(dim)\\nfor x in range(len(listo)):\\n\\tlisto[x] = int(listo[x])\\nm = listo[0]\\nn = listo[1]\\ncheck = m * n\\nif check % 2 == 1:\\n\\tprint(int((check - 1) / 2))\\nelse:\\n\\tprint(int(check / 2))\\n\",\n \"(r, c) = [int(x) for x in input().split()]\\nif r <= 1 and c <= 1:\\n\\tprint(0)\\nelse:\\n\\tprint(r * c // 2)\\n\",\n \"def NumberDominoes(M, N):\\n\\tcount = 0\\n\\tNleft = N\\n\\tcurrent = N // 2\\n\\tcount = count + current * M\\n\\tNleft = Nleft - current * 2\\n\\tif Nleft != 0:\\n\\t\\tcurrent = M // 2\\n\\t\\tcount = count + current\\n\\treturn count\\n(M, N) = map(int, input().split(' '))\\nprint(NumberDominoes(M, N))\\n\",\n \"(M, N) = map(int, input().split())\\nif M * N % 2 == 0:\\n\\tp = M * N // 2\\nelse:\\n\\tp = M * N // 2\\nprint(p)\\n\",\n \"(a, b) = [int(x) for x in input().split(' ')]\\ntotal_boxes = a * b\\ncovered = total_boxes // 2\\nprint(covered)\\n\",\n \"rect_area = input().split()\\nl = rect_area[0]\\nb = rect_area[1]\\nm = int(l)\\nn = int(b)\\ndominoes_area = 2 * 1\\nprint(m * n // dominoes_area)\\n\",\n \"n = list(map(int, input().split()))\\nx = n[0] * n[1]\\ny = x / 2\\ny = int(y)\\nprint(y)\\n\",\n \"line = input()\\nm = int(line[0:line.find(' ')])\\nn = int(line[line.find(' ') + 1:len(line)])\\nif m % 2 == 0 and n % 2 == 0:\\n\\tprint(int(m * (n / 2)))\\nelif m % 2 == 0 and n % 2 != 0 or (m % 2 != 0 and n % 2 == 0):\\n\\tprint(int(m * (n - 1) / 2 + m / 2))\\nelif m % 2 != 0 and n % 2 != 0:\\n\\tprint(int((m * n - 1) / 2))\\n\",\n \"(m, n) = [int(i) for i in input().split()]\\nif m % 2 == 0:\\n\\tprint(m // 2 * n)\\nelif n % 2 == 0:\\n\\tprint(n // 2 * m)\\nelse:\\n\\tmiddle = m // 2 * n\\n\\tborders = n // 2\\n\\tprint(middle + borders)\\n\",\n \"from collections import deque, Counter\\nimport array\\nfrom itertools import combinations, permutations\\nfrom math import sqrt\\n\\ndef read_int():\\n\\treturn int(input().strip())\\n\\ndef read_int_array():\\n\\treturn [int(i) for i in input().strip().split(' ')]\\n(n, m) = read_int_array()\\nprint(n * m // 2)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\na = m * n\\nfor i in range(1, 150):\\n\\tcurr = 2 * i\\n\\tc = i - 1\\n\\tif curr > a:\\n\\t\\tbreak\\nprint(c)\\n\",\n \"from sys import stdin\\nfrom sys import stdout\\n\\ndef dominosPilling(m, n):\\n\\treturn int(m * n / 2)\\nno_of_lines = list(map(int, str(input()).split(' ')))\\nm = no_of_lines[0]\\nn = no_of_lines[1]\\ndata = dominosPilling(m, n)\\nprint(data)\\n\",\n \"inpt = list(map(int, input().split()))\\nM = inpt[0]\\nN = inpt[1]\\nprint(M * N // 2)\\n\",\n \"mn = [int(dim) for dim in input().split()]\\nres = 2 * (mn[0] // 2) * (mn[1] // 2)\\nif mn[0] % 2 != 0:\\n\\tres += mn[1] // 2\\nif mn[1] % 2 != 0:\\n\\tres += mn[0] // 2\\nprint(res)\\n\",\n \"num = list(input().split(' '))\\nn = int(num[0])\\nm = int(num[1])\\nsum = 2\\np = 0\\nfor i in range(0, m * n):\\n\\tif sum <= m * n:\\n\\t\\tp += 1\\n\\tsum += 2\\nprint(p)\\n\",\n \"a = input()\\na = a.split()\\nb = list()\\nfor x in a:\\n\\tb.append(int(x))\\nc = 0\\nc = b[0] * b[1] / 2\\nprint(int(c))\\n\",\n \"def dimino(m, n):\\n\\ta = 2 * 1\\n\\tb = m * n\\n\\treturn int(b / a)\\n(m, n) = map(int, input().split(' '))\\nprint(dimino(m, n))\\n\",\n \"(m, n) = map(int, input().split())\\nif m % 2 is 0:\\n\\tresult = m / 2 * n\\nelif n % 2 is 0:\\n\\tresult = m * (n / 2)\\nelse:\\n\\tresult = (m - 1) / 2 * n + int(n / 2)\\nprint(int(result))\\n\",\n \"(j, k) = [int(i) for i in input().split(' ')]\\nprint(j * k // 2)\\n\",\n \"def main():\\n\\t(m, n) = map(int, input().split())\\n\\ts = m * n\\n\\tif s % 2 != 0:\\n\\t\\ts -= 1\\n\\tprint(int(s / 2))\\nmain()\\n\",\n \"parameters = input()\\nparam_list = list(map(int, parameters.split()))\\nif param_list[0] % 2 + param_list[1] % 2 <= 1:\\n\\tdomino = param_list[0] * param_list[1] / 2\\nelif param_list[0] == 1 and param_list[1] == 1:\\n\\tdomino = 0\\nelif param_list[0] == 1:\\n\\tdomino = param_list[0] * (param_list[1] - 1) / 2\\nelif param_list[1] == 1:\\n\\tdomino = param_list[1] * (param_list[0] - 1) / 2\\nelse:\\n\\tdomino = param_list[0] * (param_list[1] - 1) / 2 + (param_list[0] - 1) / 2\\nprint(int(domino))\\n\",\n \"(a, b) = input().split()\\na = int(a)\\nb = int(b)\\nif a > b:\\n\\t(a, b) = (b, a)\\nif a % 2 == 0:\\n\\tx = a // 2\\n\\ty = b\\n\\tz = x * y\\nif a % 2 == 1 and a != 1:\\n\\tx = a // 2\\n\\ty = b\\n\\tz = x * y + b // 2\\nif a == 1:\\n\\ty = b // 2\\n\\tz = y\\nprint(z)\\n\",\n \"(m, n) = input().split()\\nm = int(m)\\nn = int(n)\\nmaxn = max(m, n)\\nminn = min(m, n)\\nif maxn == 1:\\n\\tprint('0')\\nelif maxn == 2 * minn:\\n\\tprint(maxn * minn // 2)\\nelse:\\n\\tnum = maxn // 2 * minn\\n\\tif maxn % 2 == 0:\\n\\t\\tprint(num)\\n\\telse:\\n\\t\\tnum += minn // 2\\n\\t\\tprint(num)\\n\",\n \"import sys\\n(x, y) = input().split()\\nx = int(x)\\ny = int(y)\\nc = x * y\\nans = c // 2\\nprint(ans)\\n\",\n \"(m, n) = [int(x) for x in input().split()]\\ntotal = m * n // 2\\nprint(total)\\n\"\n]","isConversational":false},"starter_code":{"kind":"string","value":""},"input_output":{"kind":"string","value":"{\"inputs\": [\"2 6\\n\", \"1 5\\n\", \"3 6\\n\", \"2 5\\n\", \"3 16\\n\", \"2 7\\n\", \"3 10\\n\", \"14 16\\n\", \"1 16\\n\", \"5 16\\n\", \"4 4\\n\", \"15 16\\n\", \"5 7\\n\", \"2 16\\n\", \"2 2\\n\", \"1 6\\n\", \"1 1\\n\", \"16 16\\n\", \"14 15\\n\", \"1 4\\n\", \"2 14\\n\", \"3 15\\n\", \"2 3\\n\", \"3 4\\n\", \"11 13\\n\", \"3 5\\n\", \"3 14\\n\", \"8 15\\n\", \"15 15\\n\", \"1 2\\n\", \"1 15\\n\", \"1 3\\n\", \"2 15\\n\", \"1 7\\n\", \"4 10\\n\", \"14 14\\n\", \"10 16\\n\", \"12 16\\n\", \"1 13\\n\", \"11 15\\n\", \"1 8\\n\", \"3 8\\n\", \"3 9\\n\", \"12 15\\n\", \"1 11\\n\", \"7 10\\n\", \"2 8\\n\", \"3 7\\n\", \"9 10\\n\", \"4 7\\n\", \"4 9\\n\", \"4 8\\n\", \"3 13\\n\", \"4 11\\n\", \"4 16\\n\", \"6 16\\n\", \"4 15\\n\", \"9 15\\n\", \"8 14\\n\", \"2 11\\n\", \"4 13\\n\", \"8 10\\n\", \"4 14\\n\", \"6 8\\n\", \"6 13\\n\", \"7 15\\n\", \"2 9\\n\", \"10 14\\n\", \"8 11\\n\", \"10 15\\n\", \"5 6\\n\", \"12 13\\n\", \"5 15\\n\", \"1 14\\n\", \"5 10\\n\", \"8 16\\n\", \"7 11\\n\", \"7 12\\n\", \"6 12\\n\", \"1 9\\n\", \"6 6\\n\", \"2 10\\n\", \"4 6\\n\", \"5 5\\n\", \"2 13\\n\", \"6 15\\n\", \"5 8\\n\", \"1 10\\n\", \"3 12\\n\", \"7 16\\n\", \"4 5\\n\", \"3 11\\n\", \"5 9\\n\", \"2 12\\n\", \"6 10\\n\", \"8 8\\n\", \"7 8\\n\", \"9 9\\n\", \"7 7\\n\", \"5 13\\n\", \"1 12\\n\", \"8 13\\n\", \"5 12\\n\", \"8 9\\n\", \"2 4\\n\", \"3 3\\n\"], \"outputs\": [\"6\\n\", \"2\\n\", \"9\\n\", \"5\\n\", \"24\\n\", \"7\\n\", \"15\\n\", \"112\\n\", \"8\\n\", \"40\\n\", \"8\\n\", \"120\\n\", \"17\\n\", \"16\\n\", \"2\\n\", \"3\\n\", \"0\\n\", \"128\\n\", \"105\\n\", \"2\\n\", \"14\\n\", \"22\\n\", \"3\\n\", \"6\\n\", \"71\\n\", \"7\\n\", \"21\\n\", \"60\\n\", \"112\\n\", \"1\\n\", \"7\\n\", \"1\\n\", \"15\\n\", \"3\\n\", \"20\\n\", \"98\\n\", \"80\\n\", \"96\\n\", \"6\\n\", \"82\\n\", \"4\\n\", \"12\\n\", \"13\\n\", \"90\\n\", \"5\\n\", \"35\\n\", \"8\\n\", \"10\\n\", \"45\\n\", \"14\\n\", \"18\\n\", \"16\\n\", \"19\\n\", \"22\\n\", \"32\\n\", \"48\\n\", \"30\\n\", \"67\\n\", \"56\\n\", \"11\\n\", \"26\\n\", \"40\\n\", \"28\\n\", \"24\\n\", \"39\\n\", \"52\\n\", \"9\\n\", \"70\\n\", \"44\\n\", \"75\\n\", \"15\\n\", \"78\\n\", \"37\\n\", \"7\\n\", \"25\\n\", \"64\\n\", \"38\\n\", \"42\\n\", \"36\\n\", \"4\\n\", \"18\\n\", \"10\\n\", \"12\\n\", \"12\\n\", \"13\\n\", \"45\\n\", \"20\\n\", \"5\\n\", \"18\\n\", \"56\\n\", \"10\\n\", \"16\\n\", \"22\\n\", \"12\\n\", \"30\\n\", \"32\\n\", \"28\\n\", \"40\\n\", \"24\\n\", \"32\\n\", \"6\\n\", \"52\\n\", \"30\\n\", \"36\\n\", \"4\\n\", \"4\\n\"]}"},"difficulty":{"kind":"string","value":"EASY"},"raw_tags":{"kind":"string","value":"['greedy', 'math']"},"name":{"kind":"null"},"source":{"kind":"string","value":"codeforces"},"tags":{"kind":"string","value":"['Mathematics', 'Greedy algorithms']"},"skill_types":{"kind":"string","value":"['Greedy algorithms']"},"url":{"kind":"string","value":"https://codeforces.com/problemset/problem/50/A"},"time_limit":{"kind":"string","value":"2.0 seconds"},"date":{"kind":"null"},"picture_num":{"kind":"null"},"memory_limit":{"kind":"string","value":"256.0 megabytes"},"Expected Time Complexity":{"kind":"null"},"task_id":{"kind":"number","value":25237,"string":"25,237"},"solution_id":{"kind":"number","value":0,"string":"0"},"solution":{"kind":"string","value":"(M, N) = map(int, input().split())\nd = M * N // 2\nprint(d)\n"},"text":{"kind":"string","value":"# Question\n\nYou are given a rectangular board of M × N squares. Also you are given an unlimited number of standard domino pieces of 2 × 1 squares. You are allowed to rotate the pieces. You are asked to place as many dominoes as possible on the board so as to meet the following conditions:\n\n1. Each domino completely covers two squares.\n\n2. No two dominoes overlap.\n\n3. Each domino lies entirely inside the board. It is allowed to touch the edges of the board.\n\nFind the maximum number of dominoes, which can be placed under these restrictions.\n\nInput\n\nIn a single line you are given two integers M and N — board sizes in squares (1 ≤ M ≤ N ≤ 16).\n\nOutput\n\nOutput one number — the maximal number of dominoes, which can be placed.\n\nExamples\n\nInput\n\n2 4\n\n\nOutput\n\n4\n\n\nInput\n\n3 3\n\n\nOutput\n\n4\n\n# Solution\n\n```python\n(M, N) = map(int, input().split())\nd = M * N // 2\nprint(d)\n```"}}}],"truncated":false,"partial":false},"paginationData":{"pageIndex":194,"numItemsPerPage":100,"numTotalItems":19493,"offset":19400,"length":100}},"jwt":"eyJhbGciOiJFZERTQSJ9.eyJyZWFkIjp0cnVlLCJwZXJtaXNzaW9ucyI6eyJyZXBvLmNvbnRlbnQucmVhZCI6dHJ1ZX0sImlhdCI6MTc4MDk0MTY0OSwic3ViIjoiL2RhdGFzZXRzL0FzYXA3NzcyL1RBQ08tUHJvY2Vzc2VkIiwiZXhwIjoxNzgwOTQ1MjQ5LCJpc3MiOiJodHRwczovL2h1Z2dpbmdmYWNlLmNvIn0.UzZegcPtAXylUVulJ3zNDHYnZf2xnUmoduDbDIN7vNIR25zBF8VYnwM-IDaVGNyROC7m7LR63wfG8xQVQFMvDA","displayUrls":true,"splitSizeSummaries":[{"config":"default","split":"train","numRows":19493,"numBytesParquet":1642200412},{"config":"default","split":"test","numRows":990,"numBytesParquet":234425941}]},"discussionsStats":{"closed":0,"open":1,"total":1},"fullWidth":true,"hasGatedAccess":true,"hasFullAccess":true,"isEmbedded":false,"savedQueries":{"community":[],"user":[]}}">
question stringlengths 29 14k | solutions listlengths 1 6.39k | starter_code stringlengths 0 1.47k | input_output stringlengths 29 74M | difficulty stringclasses 6
values | raw_tags stringlengths 2 281 | name stringlengths 3 105 ⌀ | source stringclasses 10
values | tags stringlengths 2 183 | skill_types stringclasses 127
values | url stringlengths 36 138 ⌀ | time_limit stringclasses 143
values | date stringlengths 10 10 ⌀ | picture_num stringclasses 8
values | memory_limit stringclasses 28
values | Expected Time Complexity stringclasses 710
values | task_id int64 1 25.4k | solution_id int64 0 0 | solution stringlengths 6 413k | text stringlengths 123 413k |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Implement a Stack using two queues q1 and q2.
Example 1:
Input:
push(2)
push(3)
pop()
push(4)
pop()
Output: 3 4
Explanation:
push(2) the stack will be {2}
push(3) the stack will be {2 3}
pop() poped element will be 3 the
stack will be {2}
push(4) the stack will be {2 4}
pop() poped element will be 4
Exam... | [
"def push(x):\n\tglobal queue_1\n\tglobal queue_2\n\tqueue_1.append(x)\n\twhile queue_2:\n\t\tval = queue_2.pop(0)\n\t\tqueue_1.append(val)\n\t(queue_1, queue_2) = (queue_2, queue_1)\n\ndef pop():\n\tglobal queue_1\n\tglobal queue_2\n\tif not queue_2:\n\t\treturn -1\n\treturn queue_2.pop(0)\n",
"def push(x):\n\tg... | #User function Template for python3
'''
:param x: value to be inserted
:return: None
queue_1 = [] # first queue
queue_2 = [] # second queue
'''
#Function to push an element into stack using two queues.
def push(x):
# global declaration
global queue_1
global queue_2
# co... | {"fn_name": "push", "inputs": ["push(2)\npush(3)\npop()\npush(4)\npop()", "push(2)\npop()\npop()\npush(3)"], "outputs": ["3 4", "2 -1"]} | EASY | ['Stack', 'Data Structures', 'Queue', 'Design-Pattern'] | null | geeksforgeeks | ['Data structures'] | ['Data structures'] | https://practice.geeksforgeeks.org/problems/stack-using-two-queues/1 | null | null | 0 | null | O(1) for push() and O(N) for pop() (or vice-versa). | 25,328 | 0 | def push(x):
global queue_1
global queue_2
queue_1.append(x)
while queue_2:
val = queue_2.pop(0)
queue_1.append(val)
(queue_1, queue_2) = (queue_2, queue_1)
def pop():
global queue_1
global queue_2
if not queue_2:
return -1
return queue_2.pop(0)
| # Question
Implement a Stack using two queues q1 and q2.
Example 1:
Input:
push(2)
push(3)
pop()
push(4)
pop()
Output: 3 4
Explanation:
push(2) the stack will be {2}
push(3) the stack will be {2 3}
pop() poped element will be 3 the
stack will be {2}
push(4) the stack will be {2 4}
pop() poped element will... |
An employee's wallet can contain no more than M notes or coins. A boss pays his salary by the minimum notes possible. However the employee may have to leave out some money. Find how much money he has to lose if his original salary is N.
Note: The values of notes or coins available are 1000, 500, 100, 50, 20, 10, 5, 2 a... | [
"class Solution:\n\n\tdef getLoss(self, n, m):\n\t\tnotes = [1000, 500, 100, 50, 20, 10, 5, 2, 1]\n\t\tcount = 0\n\t\ti = 0\n\t\twhile count < m and n > 0:\n\t\t\tif n >= notes[i]:\n\t\t\t\tn = n - notes[i]\n\t\t\t\tcount += 1\n\t\t\telse:\n\t\t\t\ti += 1\n\t\treturn n\n",
"class Solution:\n\n\tdef getLoss(self, ... | #User function Template for python3
class Solution:
def getLoss(self, N, M):
# code here | {"inputs": ["N = 1712, M = 4", "N = 1023, M = 2"], "outputs": ["12", "3"]} | EASY | ['Algorithms', 'Mathematical'] | null | geeksforgeeks | ['Mathematics'] | [] | https://practice.geeksforgeeks.org/problems/minimum-notes-required2535/1 | null | null | 0 | null | O(1) | 25,329 | 0 | class Solution:
def getLoss(self, n, m):
notes = [1000, 500, 100, 50, 20, 10, 5, 2, 1]
count = 0
i = 0
while count < m and n > 0:
if n >= notes[i]:
n = n - notes[i]
count += 1
else:
i += 1
return n
| # Question
An employee's wallet can contain no more than M notes or coins. A boss pays his salary by the minimum notes possible. However the employee may have to leave out some money. Find how much money he has to lose if his original salary is N.
Note: The values of notes or coins available are 1000, 500, 100, 50, 20... |
Ricky has N different balls and John has R different bags. Their teacher Ms.Samara wants them to distribute these N balls into R bags such that each bag gets at least one ball.
Can you find the number of ways of doing so ?
Input:
The one and only line of input contains two numbers separated by a single space, which a... | [
"'''\n# Read input from stdin and provide input before running code\n\nname = raw_input('What is your name?\\n')\nprint 'Hi, %s.' % name\n'''\n#print 'Hello World!'\nfrom math import factorial\nn,k=list(map(int,input().split()))\nif n>=k:\n\tf=factorial(n-1)/(factorial(n-k)*factorial(k-1))\n\tprint(f%10000007)\nels... | {"inputs": ["43 42", "8 2", "11 23", "42 32", "22 19"], "outputs": ["-1", "42", "1330", "7", "1098624"]} | UNKNOWN_DIFFICULTY | [] | can-you-distribute | hackerearth | [] | [] | null | null | null | null | null | null | 25,331 | 0 | '''
# Read input from stdin and provide input before running code
name = raw_input('What is your name?\n')
print 'Hi, %s.' % name
'''
#print 'Hello World!'
from math import factorial
n,k=list(map(int,input().split()))
if n>=k:
f=factorial(n-1)/(factorial(n-k)*factorial(k-1))
print(f%10000007)
else:
print("-1")
| # Question
Ricky has N different balls and John has R different bags. Their teacher Ms.Samara wants them to distribute these N balls into R bags such that each bag gets at least one ball.
Can you find the number of ways of doing so ?
Input:
The one and only line of input contains two numbers separated by a single sp... | |
Sid is a superior salesperson. So he gets a task from his boss. The task is that he will be given some number of products say k (All the products are same) and he has to travel N cities [1...N] to sell them. The main objective of the task is that he has to try to sell the product at higher price than previous city. For... | [
"primes = [2, 3]\n\nclass Solution:\n\n\tdef primeMoney(self, arr, n):\n\t\tmaxi = max(arr)\n\t\ti = primes[-1] + 2\n\t\twhile maxi >= i:\n\t\t\tflag = True\n\t\t\tfor item in primes:\n\t\t\t\tif i % item == 0:\n\t\t\t\t\tflag = False\n\t\t\t\t\tbreak\n\t\t\tif flag:\n\t\t\t\tprimes.append(i)\n\t\t\ti += 2\n\t\tset... | #User function Template for python3
class Solution:
def primeMoney(self, arr, n):
# return (0,0)
| {"inputs": ["N = 9\nA[] = {4, 2, 3, 5, 1, 6, 7, 8, 9}", "N = 10\nA[] = {2, 3, 5, 7, 4, 1, 6, 5, 4, 8}", "N = 5\nA[] = {2, 2, 2, 2, 2}"], "outputs": ["5 7", "4 17", "1 2"]} | EASY | ['Data Structures', 'Arrays', 'Algorithms', 'Mathematical'] | null | geeksforgeeks | ['Data structures', 'Mathematics'] | ['Data structures'] | https://practice.geeksforgeeks.org/problems/sid-and-his-prime-money5736/1 | null | null | 0 | null | O(N. sqrt(N)) | 25,330 | 0 | primes = [2, 3]
class Solution:
def primeMoney(self, arr, n):
maxi = max(arr)
i = primes[-1] + 2
while maxi >= i:
flag = True
for item in primes:
if i % item == 0:
flag = False
break
if flag:
primes.append(i)
i += 2
setti = set(primes)
count = 0
summa = 0
last = 0
temp_c... | # Question
Sid is a superior salesperson. So he gets a task from his boss. The task is that he will be given some number of products say k (All the products are same) and he has to travel N cities [1...N] to sell them. The main objective of the task is that he has to try to sell the product at higher price than previo... |
Chef usually likes to play cricket, but now, he is bored of playing it too much, so he is trying new games with strings. Chef's friend Dustin gave him binary strings $S$ and $R$, each with length $N$, and told him to make them identical. However, unlike Dustin, Chef does not have any superpower and Dustin lets Chef per... | [
"for i in range(int(input())):\n\ta = int(input())\n\tb = input()\n\tc = input()\n\td = b.count('0')\n\te = c.count('0')\n\tif d == e:\n\t\tprint('YES')\n\telse:\n\t\tprint('NO')\n",
"for _ in range(int(input())):\n\tn = int(input())\n\ta = input()\n\tb = input()\n\tif a.count('1') == b.count('1'):\n\t\tprint('YE... | {"inputs": [["2", "5", "11000", "01001", "3", "110", "001"]], "outputs": [["YES", "NO"]]} | EASY | ['Data Structures', 'Arrays', 'Frequency Arrays'] | null | codechef | ['Data structures'] | ['Data structures'] | https://www.codechef.com/problems/PLAYSTR | 1 seconds | 2019-07-12 | 0 | 50000 bytes | null | 25,327 | 0 | for i in range(int(input())):
a = int(input())
b = input()
c = input()
d = b.count('0')
e = c.count('0')
if d == e:
print('YES')
else:
print('NO')
| # Question
Chef usually likes to play cricket, but now, he is bored of playing it too much, so he is trying new games with strings. Chef's friend Dustin gave him binary strings $S$ and $R$, each with length $N$, and told him to make them identical. However, unlike Dustin, Chef does not have any superpower and Dustin l... | |
Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
Example:
Input: [-2,1,-3,4,-1,2,1,-5,4],
Output: 6
Explanation: [4,-1,2,1] has the largest sum = 6.
Follow up:
If you have figured out the O(n) solution, try coding another solu... | [
"class Solution:\n\n\tdef maxSubArray(self, nums):\n\t\tmax_sum = csum = nums[0]\n\t\tfor num in nums[1:]:\n\t\t\tif num >= csum + num:\n\t\t\t\tcsum = num\n\t\t\telse:\n\t\t\t\tcsum += num\n\t\t\tif csum > max_sum:\n\t\t\t\tmax_sum = csum\n\t\treturn max_sum\n",
"class Solution:\n\n\tdef maxSubArray(self, nums):... | class Solution:
def maxSubArray(self, nums: List[int]) -> int:
| {"fn_name": "maxSubArray", "inputs": [[[-2, 1, -3, 4, -1, 2, 1, -5, 4]]], "outputs": [6]} | EASY | ['Array', 'Dynamic Programming', 'Divide and Conquer'] | null | leetcode | ['Dynamic programming', 'Data structures', 'Divide and conquer'] | ['Dynamic programming', 'Data structures'] | https://leetcode.com/problems/maximum-subarray/ | null | null | null | null | null | 25,332 | 0 | class Solution:
def maxSubArray(self, nums):
max_sum = csum = nums[0]
for num in nums[1:]:
if num >= csum + num:
csum = num
else:
csum += num
if csum > max_sum:
max_sum = csum
return max_sum
| # Question
Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
Example:
Input: [-2,1,-3,4,-1,2,1,-5,4],
Output: 6
Explanation: [4,-1,2,1] has the largest sum = 6.
Follow up:
If you have figured out the O(n) solution, try coding ... |
In Python, a string of text can be aligned left, right and center.
.ljust(width)
This method returns a left aligned string of length width.
>>> width = 20
>>> print 'HackerRank'.ljust(width,'-')
HackerRank----------
.center(width)
This method returns a centered string of length width.
>>> width = 20
>>> print '... | [
"thickness = int(input())\nc = 'H'\nfor i in range(thickness):\n\tprint((c * i).rjust(thickness - 1) + c + (c * i).ljust(thickness - 1))\nfor i in range(thickness + 1):\n\tprint((c * thickness).center(thickness * 2) + (c * thickness).center(thickness * 6))\nfor i in range((thickness + 2) // 2):\n\tprint((c * thickn... | {"inputs": ["5\n"], "outputs": [" H \n HHH \n HHHHH \n HHHHHHH \nHHHHHHHHH\n HHHHH HHHHH \n HHHHH HHHHH \n HHHHH HHHHH \n HHHHH HHHHH \n HHHHH HHHHH \n HHHHH ... | EASY | ['Python - Strings'] | null | hackerrank | ['String algorithms'] | [] | https://www.hackerrank.com/challenges/text-alignment/problem | null | null | 0 | null | null | 25,336 | 0 | thickness = int(input())
c = 'H'
for i in range(thickness):
print((c * i).rjust(thickness - 1) + c + (c * i).ljust(thickness - 1))
for i in range(thickness + 1):
print((c * thickness).center(thickness * 2) + (c * thickness).center(thickness * 6))
for i in range((thickness + 2) // 2):
print((c * thickness * 5).center... | # Question
In Python, a string of text can be aligned left, right and center.
.ljust(width)
This method returns a left aligned string of length width.
>>> width = 20
>>> print 'HackerRank'.ljust(width,'-')
HackerRank----------
.center(width)
This method returns a centered string of length width.
>>> width = 20... | |
You are given N integers \{A_{1}, A_{2}, \ldots, A_{N}\}. Determine whether they can be reordered such that each pair of consecutive differences differ by a factor of 2.
Formally, determine whether there exists a rearrangement of the given integers into an array [B_{1}, B_{2}, \ldots, B_{N}] such that, for each 2 ≤ i ... | [
"for _ in range(int(input())):\n\tn = int(input())\n\ta = sorted(list(map(int, input().split())))\n\tl = [a[i + 1] - a[i] for i in range(n - 1)]\n\tc = 0\n\tfor i in range(len(l) - 1):\n\t\tif l[i] == 2 * l[i + 1] or l[i] // 2 == l[i + 1] or 2 * l[i] == l[i + 1]:\n\t\t\tc += 1\n\t\telse:\n\t\t\tbreak\n\tif len(l) -... | {"inputs": ["4\n3\n5 2 4\n5\n2 1 16 8 4\n5\n97 98 100 96 88\n6\n16 19 18 21 24 22"], "outputs": ["Yes\nYes\nNo\nYes\n"]} | EASY | ['ad-hoc', 'trygub_adm', 'sorting', 'cook141'] | null | codechef | ['Sorting', 'Ad-hoc'] | ['Sorting'] | https://www.codechef.com/problems/DOUBLEDDIST | 1 seconds | 2022-04-28 | 0 | 50000 bytes | null | 25,334 | 0 | for _ in range(int(input())):
n = int(input())
a = sorted(list(map(int, input().split())))
l = [a[i + 1] - a[i] for i in range(n - 1)]
c = 0
for i in range(len(l) - 1):
if l[i] == 2 * l[i + 1] or l[i] // 2 == l[i + 1] or 2 * l[i] == l[i + 1]:
c += 1
else:
break
if len(l) - 1 == c:
print('Yes')
else:
... | # Question
You are given N integers \{A_{1}, A_{2}, \ldots, A_{N}\}. Determine whether they can be reordered such that each pair of consecutive differences differ by a factor of 2.
Formally, determine whether there exists a rearrangement of the given integers into an array [B_{1}, B_{2}, \ldots, B_{N}] such that, for... | |
Example
Input
4 4
1 2 3
1 3 3
2 3 3
2 4 3
Output
1 3 | [
"(N, M) = map(int, input().split())\nE0 = []\nfor i in range(M):\n\t(S, D, C) = map(int, input().split())\n\tE0.append((C, S - 1, D - 1))\nE0.sort()\n(*parent,) = range(N)\n\ndef root(x):\n\tif x == parent[x]:\n\t\treturn x\n\ty = parent[x] = root(parent[x])\n\treturn y\n\ndef unite(x, y):\n\tpx = root(x)\n\tpy = r... | {"inputs": ["4 4\n1 2 3\n1 3 3\n2 3 3\n2 4 6", "4 4\n1 2 4\n1 3 3\n2 3 3\n2 4 6", "4 4\n1 3 4\n1 3 0\n2 3 3\n2 4 6", "4 4\n1 3 4\n1 3 0\n2 3 5\n2 4 6", "4 4\n1 2 3\n1 3 3\n2 3 3\n2 4 9", "4 4\n1 4 3\n1 3 0\n2 3 5\n2 4 6", "4 4\n1 2 2\n1 3 3\n2 3 3\n2 4 3", "4 4\n1 2 4\n1 3 3\n2 3 3\n1 4 11", "4 4\n1 2 1\n1 3 3\n2 3 3\n... | UNKNOWN_DIFFICULTY | [] | null | aizu | [] | [] | null | 3.0 seconds | null | null | 268.435456 megabytes | null | 25,337 | 0 | (N, M) = map(int, input().split())
E0 = []
for i in range(M):
(S, D, C) = map(int, input().split())
E0.append((C, S - 1, D - 1))
E0.sort()
(*parent,) = range(N)
def root(x):
if x == parent[x]:
return x
y = parent[x] = root(parent[x])
return y
def unite(x, y):
px = root(x)
py = root(y)
if px < py:
parent[p... | # Question
Example
Input
4 4
1 2 3
1 3 3
2 3 3
2 4 3
Output
1 3
# Solution
```python
(N, M) = map(int, input().split())
E0 = []
for i in range(M):
(S, D, C) = map(int, input().split())
E0.append((C, S - 1, D - 1))
E0.sort()
(*parent,) = range(N)
def root(x):
if x == parent[x]:
return x
y = parent[x] = ro... | |
Jzzhu is the president of country A. There are n cities numbered from 1 to n in his country. City 1 is the capital of A. Also there are m roads connecting the cities. One can go from city ui to vi (and vise versa) using the i-th road, the length of this road is xi. Finally, there are k train routes in the country. One ... | [
"import sys\ninput = sys.stdin.readline\nimport heapq\n(n, m, k) = map(int, input().split())\nadj = [[] for _ in range(n + 5)]\nfor _ in range(m):\n\t(u, v, w) = map(int, input().split())\n\tadj[u].append((v, w))\n\tadj[v].append((u, w))\ntrain = [-1 for _ in range(n + 5)]\nans = 0\ndist = [int(1000000000000000.0) ... | {"inputs": ["5 5 2\n1 2 100\n2 3 100\n3 4 100\n4 5 20\n2 5 5\n5 50\n4 1\n", "2 1 5\n1 2 4\n2 3\n2 5\n2 4\n2 4\n2 5\n", "3 3 6\n1 2 499999999\n2 3 500000000\n1 3 999999999\n2 499999999\n2 500000000\n2 499999999\n3 999999999\n3 1000000000\n3 1000000000\n", "2 1 1\n1 2 1\n2 1000000000\n", "5 4 3\n1 2 999999999\n2 3 100000... | HARD | ['shortest paths', 'greedy', 'graphs'] | null | codeforces | ['Greedy algorithms', 'Graph algorithms', 'Shortest paths'] | ['Greedy algorithms'] | https://codeforces.com/problemset/problem/450/D | 2.0 seconds | null | null | 256.0 megabytes | null | 25,338 | 0 | import sys
input = sys.stdin.readline
import heapq
(n, m, k) = map(int, input().split())
adj = [[] for _ in range(n + 5)]
for _ in range(m):
(u, v, w) = map(int, input().split())
adj[u].append((v, w))
adj[v].append((u, w))
train = [-1 for _ in range(n + 5)]
ans = 0
dist = [int(1000000000000000.0) for _ in range(n + ... | # Question
Jzzhu is the president of country A. There are n cities numbered from 1 to n in his country. City 1 is the capital of A. Also there are m roads connecting the cities. One can go from city ui to vi (and vise versa) using the i-th road, the length of this road is xi. Finally, there are k train routes in the c... | |
In some country there are exactly n cities and m bidirectional roads connecting the cities. Cities are numbered with integers from 1 to n. If cities a and b are connected by a road, then in an hour you can go along this road either from city a to city b, or from city b to city a. The road network is such that from any ... | [
"from itertools import combinations_with_replacement\nfrom collections import deque\n(n, m) = map(int, input().split())\nG = [[] for i in range(n)]\nfor i in range(m):\n\t(x, y) = map(int, input().split())\n\tx -= 1\n\ty -= 1\n\tG[x].append(y)\n\tG[y].append(x)\n\ndef BFS(s):\n\tdist = [-1 for i in range(n)]\n\tdis... | {"inputs": ["2 1\n1 2\n1 1 0\n1 2 0\n", "1 0\n1 1 0\n1 1 0\n", "2 1\n1 2\n1 1 0\n1 2 1\n", "6 5\n1 2\n2 3\n3 4\n3 5\n2 6\n1 4 3\n5 6 3\n", "9 9\n1 2\n2 3\n2 4\n4 5\n5 7\n5 6\n3 8\n8 9\n9 6\n1 7 4\n3 6 3\n", "10 11\n1 3\n2 3\n3 4\n4 5\n4 6\n3 7\n3 8\n4 9\n4 10\n7 9\n8 10\n1 5 3\n6 2 3\n", "6 5\n1 3\n2 3\n3 4\n4 5\n4 6\n... | HARD | ['shortest paths', 'graphs', 'constructive algorithms'] | null | codeforces | ['Graph algorithms', 'Shortest paths', 'Constructive algorithms'] | [] | https://codeforces.com/problemset/problem/544/D | 2.0 seconds | null | null | 256.0 megabytes | null | 25,339 | 0 | from itertools import combinations_with_replacement
from collections import deque
(n, m) = map(int, input().split())
G = [[] for i in range(n)]
for i in range(m):
(x, y) = map(int, input().split())
x -= 1
y -= 1
G[x].append(y)
G[y].append(x)
def BFS(s):
dist = [-1 for i in range(n)]
dist[s] = 0
Q = deque()
Q.... | # Question
In some country there are exactly n cities and m bidirectional roads connecting the cities. Cities are numbered with integers from 1 to n. If cities a and b are connected by a road, then in an hour you can go along this road either from city a to city b, or from city b to city a. The road network is such th... | |
Alexa has two stacks of non-negative integers, stack $a[n]$ and stack $b[m]$ where index $0$ denotes the top of the stack. Alexa challenges Nick to play the following game:
In each move, Nick can remove one integer from the top of either stack $\class{ML__boldsymbol}{\boldsymbol{a}}$ or stack $\boldsymbol{b}$.
Nick ke... | [
"import sys\ng = int(input().strip())\nfor a0 in range(g):\n\t(n, m, x) = input().strip().split(' ')\n\t(n, m, x) = [int(n), int(m), int(x)]\n\ta = list(map(int, input().strip().split(' ')))\n\tb = list(map(int, input().strip().split(' ')))\n\ti = 0\n\twhile i < len(a) and x >= a[i]:\n\t\tx -= a[i]\n\t\ti += 1\n\ta... | {"inputs": ["1\n5 4 10\n4 2 4 6 1\n2 1 8 5\n"], "outputs": ["4\n"]} | MEDIUM | ['Data Structures - Stacks'] | null | hackerrank | ['Data structures'] | ['Data structures'] | https://www.hackerrank.com/challenges/game-of-two-stacks/problem | null | null | 2 | null | null | 25,333 | 0 | import sys
g = int(input().strip())
for a0 in range(g):
(n, m, x) = input().strip().split(' ')
(n, m, x) = [int(n), int(m), int(x)]
a = list(map(int, input().strip().split(' ')))
b = list(map(int, input().strip().split(' ')))
i = 0
while i < len(a) and x >= a[i]:
x -= a[i]
i += 1
ans = i
j = 0
for p in b:
... | # Question
Alexa has two stacks of non-negative integers, stack $a[n]$ and stack $b[m]$ where index $0$ denotes the top of the stack. Alexa challenges Nick to play the following game:
In each move, Nick can remove one integer from the top of either stack $\class{ML__boldsymbol}{\boldsymbol{a}}$ or stack $\boldsymbol{... | |
A tennis tournament is about to take place with $N$ players participating in it.
Every player plays with every other player exactly once and there are no ties. That is, every match has a winner and a loser.
With Naman's birthday approaching, he wants to make sure that each player wins the same number of matches so tha... | [
"from math import comb\na = int(input())\nfor i in range(a):\n\tN = int(input())\n\tmatche = comb(N, 2)\n\twin = matche / N\n\tans = []\n\tif win != int(win):\n\t\tprint('NO')\n\t\tcontinue\n\tprint('YES')\n\tfor k in range(N):\n\t\tlist = []\n\t\tfor j in range(N):\n\t\t\tlist.append(0)\n\t\tans.append(list)\n\t\t... | {"inputs": [["2", "3", "2"]], "outputs": [["YES", "010", "001", "100", "NO"]]} | MEDIUM | ['Algorithms', 'ad-hoc', 'Observation', 'Constructive'] | null | codechef | ['Constructive algorithms', 'Ad-hoc'] | [] | https://www.codechef.com/problems/EXUNB | 1 seconds | 2019-09-25 | 0 | 50000 bytes | null | 25,340 | 0 | from math import comb
a = int(input())
for i in range(a):
N = int(input())
matche = comb(N, 2)
win = matche / N
ans = []
if win != int(win):
print('NO')
continue
print('YES')
for k in range(N):
list = []
for j in range(N):
list.append(0)
ans.append(list)
list = []
for k in range(N):
temp = win
... | # Question
A tennis tournament is about to take place with $N$ players participating in it.
Every player plays with every other player exactly once and there are no ties. That is, every match has a winner and a loser.
With Naman's birthday approaching, he wants to make sure that each player wins the same number of ma... | |
Given a set of $N$ axis-aligned rectangular seals, find the number of overlapped seals on the region which has the maximum number of overlapped seals.
Constraints
* $ 1 \leq N \leq 100000 $
* $ 0 \leq x1_i < x2_i \leq 1000 $
* $ 0 \leq y1_i < y2_i \leq 1000 $
* $ x1_i, y1_i, x2_i, y2_i$ are given in integers
Input
... | [
"from itertools import accumulate\nimport sys\nn = int(input())\nys = [0] * 1001\nrects = [None] * 2 * n\ni = 0\nfor line in sys.stdin:\n\t(x1, y1, x2, y2) = [int(j) for j in line.split()]\n\trects[i] = (x2, -1, y1, y2)\n\trects[i + n] = (x1, 1, y1, y2)\n\ti += 1\nrects.sort(key=lambda x: x[0])\nmax_overlap = 0\nfo... | {"inputs": ["2\n0 0 2 2\n2 0 4 4", "3\n0 0 1 2\n0 0 2 2\n0 0 2 2", "2\n0 0 3 2\n2 1 4 2", "2\n0 0 0 1\n2 2 4 2", "2\n0 0 3 1\n2 1 4 3", "2\n0 0 3 1\n2 1 4 2", "2\n0 0 3 1\n2 1 4 4", "2\n0 0 2 2\n2 0 2 2", "3\n0 0 2 4\n0 0 2 2\n0 0 2 2", "3\n0 0 1 2\n0 0 2 3\n0 0 2 2", "2\n0 0 3 1\n2 1 2 3", "2\n0 0 3 1\n2 2 4 2", "2\n0... | UNKNOWN_DIFFICULTY | [] | null | aizu | [] | [] | null | 1.0 seconds | null | null | 134.217728 megabytes | null | 25,342 | 0 | from itertools import accumulate
import sys
n = int(input())
ys = [0] * 1001
rects = [None] * 2 * n
i = 0
for line in sys.stdin:
(x1, y1, x2, y2) = [int(j) for j in line.split()]
rects[i] = (x2, -1, y1, y2)
rects[i + n] = (x1, 1, y1, y2)
i += 1
rects.sort(key=lambda x: x[0])
max_overlap = 0
for (x, t, y1, y2) in re... | # Question
Given a set of $N$ axis-aligned rectangular seals, find the number of overlapped seals on the region which has the maximum number of overlapped seals.
Constraints
* $ 1 \leq N \leq 100000 $
* $ 0 \leq x1_i < x2_i \leq 1000 $
* $ 0 \leq y1_i < y2_i \leq 1000 $
* $ x1_i, y1_i, x2_i, y2_i$ are given in integ... | |
You are given an array of integers $a_1, a_2, \ldots, a_n$ and an integer $x$.
You need to select the maximum number of elements in the array, such that for every subsegment $a_l, a_{l + 1}, \ldots, a_r$ containing strictly more than one element $(l < r)$, either:
At least one element on this subsegment is not select... | [
"for _ in range(int(input())):\n\tn = int(input())\n\ta = list(map(int, input().split()))\n\tx = int(input())\n\ta = [c - x for c in a]\n\tbegin = True\n\tunchosen = 0\n\tsum = 0\n\tfor i in range(n):\n\t\tif begin:\n\t\t\tsum = a[i]\n\t\t\tbegin = False\n\t\telse:\n\t\t\tsum += a[i]\n\t\t\tif sum < 0:\n\t\t\t\tbeg... | {"inputs": ["4\n5\n1 2 3 4 5\n2\n10\n2 4 2 4 2 4 2 4 2 4\n3\n3\n-10 -5 -10\n-8\n3\n9 9 -3\n5\n", "1\n10\n5 -9 -1 6 -6 5 -6 -8 5 3\n0\n", "10\n1\n62169\n62169\n1\n49900\n49900\n1\n-45220\n-45220\n1\n45734\n45734\n1\n-77581\n-77581\n1\n-48287\n-48287\n1\n53304\n53304\n1\n13558\n13558\n1\n18202\n18202\n1\n33613\n33613\n",... | HARD | ['greedy', 'math', 'dp'] | null | codeforces | ['Dynamic programming', 'Mathematics', 'Greedy algorithms'] | ['Dynamic programming', 'Greedy algorithms'] | https://codeforces.com/problemset/problem/1616/D | 1.5 seconds | 2021-12-29 | 0 | 256 megabytes | null | 25,343 | 0 | for _ in range(int(input())):
n = int(input())
a = list(map(int, input().split()))
x = int(input())
a = [c - x for c in a]
begin = True
unchosen = 0
sum = 0
for i in range(n):
if begin:
sum = a[i]
begin = False
else:
sum += a[i]
if sum < 0:
begin = True
unchosen += 1
else:
sum = m... | # Question
You are given an array of integers $a_1, a_2, \ldots, a_n$ and an integer $x$.
You need to select the maximum number of elements in the array, such that for every subsegment $a_l, a_{l + 1}, \ldots, a_r$ containing strictly more than one element $(l < r)$, either:
At least one element on this subsegment i... | |
It is 2050 and romance has long gone, relationships exist solely for practicality.
MatchMyHusband is a website that matches busy working women with perfect house husbands. You have been employed by MatchMyHusband to write a function that determines who matches!!
The rules are... a match occurs providing the husband's... | [
"def match(usefulness, months):\n\treturn 'Match!' if sum(usefulness) >= 0.85 ** months * 100 else 'No match!'\n",
"def current(usefulness):\n\treturn sum(usefulness)\n\ndef needed(months):\n\tif months == 0:\n\t\treturn 100\n\telse:\n\t\treturn 0.85 * needed(months - 1)\n\ndef match(usefulness, months):\n\tif cu... | def match(usefulness, months):
| {"fn_name": "match", "inputs": [[[15, 24, 12], 4], [[26, 23, 19], 3], [[11, 25, 36], 1], [[22, 9, 24], 5], [[8, 11, 4], 10], [[17, 31, 21], 2], [[34, 25, 36], 1], [[35, 35, 29], 0], [[35, 35, 30], 0], [[35, 35, 31], 0]], "outputs": [["No match!"], ["Match!"], ["No match!"], ["Match!"], ["Match!"], ["No match!"], ["Matc... | EASY | ['Mathematics', 'Algorithms', 'Fundamentals'] | null | codewars | ['Fundamentals', 'Mathematics'] | [] | https://www.codewars.com/kata/5750699bcac40b3ed80001ca | null | null | null | null | null | 25,345 | 0 | def match(usefulness, months):
return 'Match!' if sum(usefulness) >= 0.85 ** months * 100 else 'No match!'
| # Question
It is 2050 and romance has long gone, relationships exist solely for practicality.
MatchMyHusband is a website that matches busy working women with perfect house husbands. You have been employed by MatchMyHusband to write a function that determines who matches!!
The rules are... a match occurs providing t... |
Problem Statement
Mr. Takatsuki, who is planning to participate in the Aizu training camp, has a poor house and always tries to save as much paper as possible. She decided to play a ghost leg with other participants to decide the team for the Aizu training camp.
How to make Amidakuji for this training camp is as foll... | [
"from itertools import permutations\n(N, M) = map(int, input().split())\nk = [int(input()) - 1 for i in range(M)]\ng = [i for i in range(N)]\nfor i in range(N):\n\tfor j in k:\n\t\tif g[i] == j:\n\t\t\tg[i] = j + 1\n\t\telif g[i] == j + 1:\n\t\t\tg[i] = j\ns = 10\nfor K in permutations(k):\n\tG = [i for i in range(... | {"inputs": ["6 4\n4\n3\n1\n2", "4 3\n2\n2\n4", "13 1\n7\n4\n3", "6 4\n1\n2\n1\n2", "4 3\n2\n2\n3", "5 3\n2\n2\n3", "4 3\n2\n3\n4", "4 3\n3\n3\n4", "6 4\n4\n1\n1\n2", "5 3\n4\n2\n3", "9 3\n4\n2\n3", "9 3\n4\n2\n4", "4 3\n1\n2\n2", "10 4\n4\n3\n1\n2", "7 3\n2\n2\n4", "9 3\n2\n2\n3", "6 3\n2\n3\n4", "4 3\n3\n4\n4", "12 4\... | UNKNOWN_DIFFICULTY | [] | null | aizu | [] | [] | null | 1.0 seconds | null | null | 134.217728 megabytes | null | 25,351 | 0 | from itertools import permutations
(N, M) = map(int, input().split())
k = [int(input()) - 1 for i in range(M)]
g = [i for i in range(N)]
for i in range(N):
for j in k:
if g[i] == j:
g[i] = j + 1
elif g[i] == j + 1:
g[i] = j
s = 10
for K in permutations(k):
G = [i for i in range(N)]
for i in range(N):
for... | # Question
Problem Statement
Mr. Takatsuki, who is planning to participate in the Aizu training camp, has a poor house and always tries to save as much paper as possible. She decided to play a ghost leg with other participants to decide the team for the Aizu training camp.
How to make Amidakuji for this training cam... | |
A number is called faithful if you can write it as the sum of distinct powers of 7.
e.g., 2457 = 7 + 7^{2} + 7^{4 . }If we order all the faithful numbers, we get the sequence 1 = 7^{0}, 7 = 7^{1}, 8 = 7^{0} + 7^{1}, 49 = 7^{2}, 50 = 7^{0} + 7^{2} . . . and so on.
Given some value of N, you have to find the N'th faith... | [
"class Solution:\n\n\tdef nthFaithfulNum(self, N):\n\t\tans = 0\n\t\tpower = 0\n\t\twhile N:\n\t\t\tif N & 1:\n\t\t\t\tans = ans + pow(7, power)\n\t\t\tpower = power + 1\n\t\t\tN = N // 2\n\t\treturn ans\n",
"class Solution:\n\n\tdef nthFaithfulNum(self, N):\n\t\td = 1\n\t\ti = 1\n\t\tres = 0\n\t\twhile i <= N:\n... | #User function Template for python3
class Solution:
def nthFaithfulNum(self, N):
# code here | {"inputs": ["N = 3", "N = 7"], "outputs": ["8", "57"]} | EASY | ['Algorithms', 'Mathematical'] | null | geeksforgeeks | ['Mathematics'] | [] | https://practice.geeksforgeeks.org/problems/faithful-numbers0014/1 | null | null | 0 | null | O(log(N)) | 25,347 | 0 | class Solution:
def nthFaithfulNum(self, N):
ans = 0
power = 0
while N:
if N & 1:
ans = ans + pow(7, power)
power = power + 1
N = N // 2
return ans
| # Question
A number is called faithful if you can write it as the sum of distinct powers of 7.
e.g., 2457 = 7 + 7^{2} + 7^{4 . }If we order all the faithful numbers, we get the sequence 1 = 7^{0}, 7 = 7^{1}, 8 = 7^{0} + 7^{1}, 49 = 7^{2}, 50 = 7^{0} + 7^{2} . . . and so on.
Given some value of N, you have to find th... |
Given an array Arr of size N, print second largest distinct element from an array.
Example 1:
Input:
N = 6
Arr[] = {12, 35, 1, 10, 34, 1}
Output: 34
Explanation: The largest element of the
array is 35 and the second largest element
is 34.
Example 2:
Input:
N = 3
Arr[] = {10, 5, 10}
Output: 5
Explanation: The largest... | [
"class Solution:\n\n\tdef print2largest(self, arr, n):\n\t\tif n < 2:\n\t\t\treturn -1\n\t\t(largest, second_largest) = (float('-inf'), float('-inf'))\n\t\tfor i in range(n):\n\t\t\tif arr[i] > largest:\n\t\t\t\tsecond_largest = largest\n\t\t\t\tlargest = arr[i]\n\t\t\telif arr[i] > second_largest and arr[i] != lar... | #User function Template for python3
class Solution:
def print2largest(self,arr, n):
# code here | {"inputs": ["N = 6\nArr[] = {12, 35, 1, 10, 34, 1}", "N = 3\nArr[] = {10, 5, 10}"], "outputs": ["34", "5"]} | EASY | ['Data Structures', 'Arrays', 'Searching', 'Algorithms'] | null | geeksforgeeks | ['Data structures', 'Complete search'] | ['Data structures', 'Complete search'] | https://practice.geeksforgeeks.org/problems/second-largest3735/1 | null | null | 0 | null | O(N) | 25,350 | 0 | class Solution:
def print2largest(self, arr, n):
if n < 2:
return -1
(largest, second_largest) = (float('-inf'), float('-inf'))
for i in range(n):
if arr[i] > largest:
second_largest = largest
largest = arr[i]
elif arr[i] > second_largest and arr[i] != largest:
second_largest = arr[i]
if ... | # Question
Given an array Arr of size N, print second largest distinct element from an array.
Example 1:
Input:
N = 6
Arr[] = {12, 35, 1, 10, 34, 1}
Output: 34
Explanation: The largest element of the
array is 35 and the second largest element
is 34.
Example 2:
Input:
N = 3
Arr[] = {10, 5, 10}
Output: 5
Explanation:... |
There is a rectangular room, covered with square tiles. Each tile is colored either red or black. A man is standing on a black tile. From a tile, he can move to one of four adjacent tiles. But he can't move on red tiles, he can move only on black tiles.
Write a program to count the number of black tiles which he can r... | [
"from collections import deque\ny = [-1, 0, 1, 0]\nx = [0, -1, 0, 1]\n\ndef main():\n\t(h, w) = (0, 0)\n\tc = []\n\n\tdef check(i, j):\n\t\treturn 0 <= i and i < h and (0 <= j) and (j < w)\n\n\tdef bfs(a, b):\n\t\tres = 0\n\t\td = deque()\n\t\td.append([a, b])\n\t\tf = [[False] * w for _ in range(h)]\n\t\twhile len... | {"inputs": ["6 9\n....#.\n.....#\n......\n......\n......\n......\n......\n@...#\n.#..#.\n11 9\n.#.........\n.#.#######.\n.#.#.....#.\n.#.#.###.#.\n.#.#..@#.#.\n.#.#####.#.\n.#.......#.\n.#########.\n...........\n11 6\n..#..#..#..\n..#..#..#..\n..#..#..###\n..#..#..#@.\n..#..#..#..\n..#..#..#..\n7 7\n#.#....\n..#.#..\n.... | UNKNOWN_DIFFICULTY | [] | null | aizu | [] | [] | null | 1.0 seconds | null | null | 134.217728 megabytes | null | 25,349 | 0 | from collections import deque
y = [-1, 0, 1, 0]
x = [0, -1, 0, 1]
def main():
(h, w) = (0, 0)
c = []
def check(i, j):
return 0 <= i and i < h and (0 <= j) and (j < w)
def bfs(a, b):
res = 0
d = deque()
d.append([a, b])
f = [[False] * w for _ in range(h)]
while len(d):
(i, j) = d.popleft()
if no... | # Question
There is a rectangular room, covered with square tiles. Each tile is colored either red or black. A man is standing on a black tile. From a tile, he can move to one of four adjacent tiles. But he can't move on red tiles, he can move only on black tiles.
Write a program to count the number of black tiles wh... | |
While resting on the ship after the "Russian Code Cup" a boy named Misha invented an interesting game. He promised to give his quadrocopter to whoever will be the first one to make a rectangular table of size n × m, consisting of positive integers such that the sum of the squares of numbers for each row and each column... | [
"class InputHandlerObject(object):\n\tinputs = []\n\n\tdef getInput(self, n=0):\n\t\tres = ''\n\t\tinputs = self.inputs\n\t\tif not inputs:\n\t\t\tinputs.extend(input().split(' '))\n\t\tif n == 0:\n\t\t\tres = inputs[:]\n\t\t\tinputs[:] = []\n\t\twhile n > len(inputs):\n\t\t\tinputs.extend(input().split(' '))\n\t\t... | {"inputs": ["4 23\n", "2 1\n", "33 1\n", "3 75\n", "77 93\n", "1 4\n", "7 14\n", "4 1\n", "2 11\n", "100 100\n", "77 20\n", "58 2\n", "30 31\n", "48 2\n", "48 24\n", "2 4\n", "3 1\n", "33 2\n", "3 57\n", "77 57\n", "1 3\n", "12 14\n", "8 1\n", "4 11\n", "59 20\n", "77 2\n", "43 31\n", "48 3\n", "47 24\n", "2 2\n", "33 ... | VERY_HARD | ['probabilities', 'math', 'constructive algorithms'] | null | codeforces | ['Constructive algorithms', 'Mathematics', 'Probability'] | [] | https://codeforces.com/problemset/problem/418/C | 1.0 seconds | null | null | 256.0 megabytes | null | 25,353 | 0 | class InputHandlerObject(object):
inputs = []
def getInput(self, n=0):
res = ''
inputs = self.inputs
if not inputs:
inputs.extend(input().split(' '))
if n == 0:
res = inputs[:]
inputs[:] = []
while n > len(inputs):
inputs.extend(input().split(' '))
if n > 0:
res = inputs[:n]
inputs[:n] ... | # Question
While resting on the ship after the "Russian Code Cup" a boy named Misha invented an interesting game. He promised to give his quadrocopter to whoever will be the first one to make a rectangular table of size n × m, consisting of positive integers such that the sum of the squares of numbers for each row and... | |
Polycarpus works as a DJ in the best Berland nightclub, and he often uses dubstep music in his performance. Recently, he has decided to take a couple of old songs and make dubstep remixes from them.
Let's assume that a song consists of some number of words (that don't contain WUB). To make the dubstep remix of this so... | [
"def song_decoder(song):\n\treturn ' '.join(song.replace('WUB', ' ').split())\n",
"def song_decoder(song):\n\timport re\n\treturn re.sub('(WUB)+', ' ', song).strip()\n",
"def song_decoder(song):\n\treturn ' '.join([a for a in song.split('WUB') if a])\n",
"def song_decoder(song):\n\tlist = filter(lambda x: x !... | def song_decoder(song):
| {"fn_name": "song_decoder", "inputs": [["AWUBBWUBC"], ["AWUBWUBWUBBWUBWUBWUBC"], ["WUBAWUBBWUBCWUB"], ["RWUBWUBWUBLWUB"], ["WUBJKDWUBWUBWBIRAQKFWUBWUBYEWUBWUBWUBWVWUBWUB"], ["WUBKSDHEMIXUJWUBWUBRWUBWUBWUBSWUBWUBWUBHWUBWUBWUB"], ["QWUBQQWUBWUBWUBIWUBWUBWWWUBWUBWUBJOPJPBRH"], ["WUBWUBOWUBWUBWUBIPVCQAFWYWUBWUBWUBQWUBWUBWU... | EASY | [] | null | codewars | [] | [] | https://www.codewars.com/kata/551dc350bf4e526099000ae5 | null | null | null | null | null | 25,354 | 0 | def song_decoder(song):
return ' '.join(song.replace('WUB', ' ').split())
| # Question
Polycarpus works as a DJ in the best Berland nightclub, and he often uses dubstep music in his performance. Recently, he has decided to take a couple of old songs and make dubstep remixes from them.
Let's assume that a song consists of some number of words (that don't contain WUB). To make the dubstep remi... |
Recently Vasya learned that, given two points with different x coordinates, you can draw through them exactly one parabola with equation of type y = x^2 + bx + c, where b and c are reals. Let's call such a parabola an U-shaped one.
Vasya drew several distinct points with integer coordinates on a plane and then drew an... | [
"import sys\n\ndef cross(o, a, b):\n\treturn (a[0] - o[0]) * (b[1] - o[1]) - (a[1] - o[1]) * (b[0] - o[0])\nN = int(input())\nA = [None] * N\nfor i in range(N):\n\t(x, y) = map(int, sys.stdin.readline().split())\n\tA[i] = (x, y - x * x)\nA.sort()\nupper = []\nfor p in reversed(A):\n\twhile len(upper) >= 2 and cross... | {"inputs": ["1\n-751115 -925948\n", "1\n-751115 -1566406\n", "3\n-1 -1\n0 2\n1 0\n", "3\n0 -1\n0 2\n2 0\n", "1\n-751115 -2469241\n", "3\n-1 -1\n0 2\n2 0\n", "1\n-751115 -4760337\n", "1\n-751115 -4345366\n", "3\n0 -1\n0 2\n1 0\n", "1\n-751115 -8685961\n", "3\n0 -1\n0 2\n1 -1\n", "1\n-751115 -16747294\n", "3\n0 -1\n0 2\n... | VERY_HARD | ['geometry'] | null | codeforces | ['Geometry'] | [] | https://codeforces.com/problemset/problem/1143/F | 1.0 seconds | null | null | 256.0 megabytes | null | 25,360 | 0 | import sys
def cross(o, a, b):
return (a[0] - o[0]) * (b[1] - o[1]) - (a[1] - o[1]) * (b[0] - o[0])
N = int(input())
A = [None] * N
for i in range(N):
(x, y) = map(int, sys.stdin.readline().split())
A[i] = (x, y - x * x)
A.sort()
upper = []
for p in reversed(A):
while len(upper) >= 2 and cross(upper[-2], upper[-1]... | # Question
Recently Vasya learned that, given two points with different x coordinates, you can draw through them exactly one parabola with equation of type y = x^2 + bx + c, where b and c are reals. Let's call such a parabola an U-shaped one.
Vasya drew several distinct points with integer coordinates on a plane and ... | |
Given N bits to an AND - Gate find the output that will be produced.
AND - Gate Table:
1 & 1 = 1
1 & 0 = 0
0 & 1 = 0
0 & 0 = 0
Example 1:
Input:
N = 4
arr: 1 1 1 0
Output:
0
Explanation:
1 & 1 = 1
1 & 1 = 1
1 & 0 = 0
hence output is 0
Example 2:
Input:
N = 4
arr: 0 0 1 0
Output:
0
Explanation:
0 & 0 = 0
0 & 1 = 0
0 ... | [
"class Solution:\n\n\tdef andGate(self, arr, N):\n\t\tif 0 in arr:\n\t\t\treturn 0\n\t\treturn 1\n",
"class Solution:\n\n\tdef andGate(self, arr, N):\n\t\tfor i in range(N):\n\t\t\tif arr[i] == 0:\n\t\t\t\treturn 0\n\t\treturn 1\n",
"class Solution:\n\n\tdef andGate(self, arr, N):\n\t\toutput = 1\n\t\tfor item ... | #User function Template for python3
class Solution:
def andGate (self, arr, N):
# code here | {"inputs": ["N = 4\narr:1 1 1 0", "N = 4\narr:0 0 1 0"], "outputs": ["0", "0"]} | EASY | ['Data Structures', 'Bit Magic'] | null | geeksforgeeks | ['Bit manipulation', 'Data structures'] | ['Bit manipulation', 'Data structures'] | https://practice.geeksforgeeks.org/problems/the-and-gate1231/1 | null | null | 0 | null | O(N) | 25,361 | 0 | class Solution:
def andGate(self, arr, N):
if 0 in arr:
return 0
return 1
| # Question
Given N bits to an AND - Gate find the output that will be produced.
AND - Gate Table:
1 & 1 = 1
1 & 0 = 0
0 & 1 = 0
0 & 0 = 0
Example 1:
Input:
N = 4
arr: 1 1 1 0
Output:
0
Explanation:
1 & 1 = 1
1 & 1 = 1
1 & 0 = 0
hence output is 0
Example 2:
Input:
N = 4
arr: 0 0 1 0
Output:
0
Explanation:
0 & 0 = 0
... |
# Valid HK Phone Number
## Overview
In Hong Kong, a valid phone number has the format ```xxxx xxxx``` where ```x``` is a decimal digit (0-9). For example:
## Task
Define two functions, ```isValidHKPhoneNumber``` and ```hasValidHKPhoneNumber```, that ```return```s whether a given string is a valid HK phone number a... | [
"import re\nHK_PHONE_NUMBER = '\\\\d{4} \\\\d{4}'\n\ndef is_valid_HK_phone_number(number):\n\treturn bool(re.match(HK_PHONE_NUMBER + '\\\\Z', number))\n\ndef has_valid_HK_phone_number(number):\n\treturn bool(re.search(HK_PHONE_NUMBER, number))\n",
"from re import match, search\nis_valid_HK_phone_number = lambda n... | def is_valid_HK_phone_number(number):
| {"fn_name": "is_valid_HK_phone_number", "inputs": [["1234 5678"], ["2359 1478"], ["85748475"], ["3857 4756"], ["sklfjsdklfjsf"], [" 1234 5678 "], ["abcd efgh"], ["9684 2396"], ["836g 2986"], ["0000 0000"], ["123456789"], [" 987 634 "], [" 6 "], ["8A65 2986"], ["8368 2aE6"], ["8c65 2i86"]], "outputs": [[tru... | EASY | ['Regular Expressions', 'Fundamentals'] | null | codewars | ['Fundamentals'] | [] | https://www.codewars.com/kata/56f54d45af5b1fec4b000cce | null | null | null | null | null | 25,364 | 0 | import re
HK_PHONE_NUMBER = '\\d{4} \\d{4}'
def is_valid_HK_phone_number(number):
return bool(re.match(HK_PHONE_NUMBER + '\\Z', number))
def has_valid_HK_phone_number(number):
return bool(re.search(HK_PHONE_NUMBER, number))
| # Question
# Valid HK Phone Number
## Overview
In Hong Kong, a valid phone number has the format ```xxxx xxxx``` where ```x``` is a decimal digit (0-9). For example:
## Task
Define two functions, ```isValidHKPhoneNumber``` and ```hasValidHKPhoneNumber```, that ```return```s whether a given string is a valid HK ph... |
Takahashi Lake has a perimeter of L. On the circumference of the lake, there is a residence of the lake's owner, Takahashi. Each point on the circumference of the lake has a coordinate between 0 and L (including 0 but not L), which is the distance from the Takahashi's residence, measured counter-clockwise.
There are N... | [
"(l, n) = [int(item) for item in input().split()]\nright = []\nleft = []\nfor i in range(n):\n\ta = int(input())\n\tright.append(a)\n\tleft.append(l - a)\nleft.reverse()\nrsum = [0] * (n + 1)\nlsum = [0] * (n + 1)\nfor i in range(n):\n\trsum[i + 1] += rsum[i] + right[i]\n\tlsum[i + 1] += lsum[i] + left[i]\nans = ma... | {"inputs": ["314159265 7\n21662711\n77271666\n89022761\n156626166\n160332356\n166902656\n453863319", "6 6\n1\n2\n3\n6\n7\n9", "10 3\n2\n7\n17", "391985414 7\n21662711\n77271666\n89022761\n156626166\n160332356\n166902656\n453863319", "10 3\n2\n7\n20", "10 3\n2\n7\n29", "3 6\n1\n2\n3\n6\n7\n9", "10 3\n2\n7\n28", "6 6\n1\... | UNKNOWN_DIFFICULTY | [] | AtCoder Grand Contest 030 - Tree Burning | atcoder | [] | [] | null | 2.0 seconds | null | null | 1024.0 megabytes | null | 25,358 | 0 | (l, n) = [int(item) for item in input().split()]
right = []
left = []
for i in range(n):
a = int(input())
right.append(a)
left.append(l - a)
left.reverse()
rsum = [0] * (n + 1)
lsum = [0] * (n + 1)
for i in range(n):
rsum[i + 1] += rsum[i] + right[i]
lsum[i + 1] += lsum[i] + left[i]
ans = max(right[-1], left[-1])
... | # Question
Takahashi Lake has a perimeter of L. On the circumference of the lake, there is a residence of the lake's owner, Takahashi. Each point on the circumference of the lake has a coordinate between 0 and L (including 0 but not L), which is the distance from the Takahashi's residence, measured counter-clockwise.
... | |
Like any good boss, the Chef has delegated all cooking jobs to his employees so he can take care of other tasks. Occasionally, one of the cooks needs a tool that is out of reach. In some of these cases, the cook cannot leave their workstation to get the tool because they have to closely watch their food. In such cases,... | [
"def dist(pos1: list, pos2: list) -> int:\n\treturn abs(pos1[0] - pos2[0]) + abs(pos1[1] - pos2[1])\n\ndef list2bin(n: int, lst: list) -> str:\n\tnum = 0\n\tfor x in lst:\n\t\tnum += 1 << x\n\treturn f'{num:08b}'\n\ndef pos2str(pos: list) -> str:\n\treturn '--'.join(map(str, pos))\n\ndef min_chef(chefs: list, tools... | {"inputs": ["3\n2\n1 0 0 1\n0 0 1 1\n3\n0 3 0 1\n0 4 0 2\n0 5 0 3\n3\n0 1 0 2\n0 1 0 2\n0 1 0 2"], "outputs": ["4\n10\n6"]} | MEDIUM_HARD | ['Algorithms', 'Cycles', 'Graph Algos', 'Hamiltonian Cycle', 'Dynamic Programming'] | null | codechef | ['Dynamic programming', 'Paths and circuits', 'Graph traversal', 'Graph algorithms'] | ['Dynamic programming'] | https://www.codechef.com/problems/TOOLS | 0.710216 seconds | 2010-08-09 | 0 | 50000 bytes | null | 25,369 | 0 | def dist(pos1: list, pos2: list) -> int:
return abs(pos1[0] - pos2[0]) + abs(pos1[1] - pos2[1])
def list2bin(n: int, lst: list) -> str:
num = 0
for x in lst:
num += 1 << x
return f'{num:08b}'
def pos2str(pos: list) -> str:
return '--'.join(map(str, pos))
def min_chef(chefs: list, tools: list, htools: list, re... | # Question
Like any good boss, the Chef has delegated all cooking jobs to his employees so he can take care of other tasks. Occasionally, one of the cooks needs a tool that is out of reach. In some of these cases, the cook cannot leave their workstation to get the tool because they have to closely watch their food. In... | |
Seyyed and MoJaK are friends of Sajjad. Sajjad likes a permutation. Seyyed wants to change the permutation in a way that Sajjad won't like it. Seyyed thinks more swaps yield more probability to do that, so he makes MoJaK to perform a swap between every pair of positions (i, j), where i < j, exactly once. MoJaK doesn't ... | [
"n = int(input())\np = lambda a, b: print(a + 1, b + 1)\nif n % 4 > 1:\n\tprint('NO')\nelse:\n\tprint('YES')\n\tfor i in range(n % 4, n, 4):\n\t\tfor x in range(2):\n\t\t\tfor j in range(i):\n\t\t\t\tp(j, i + 2 * x)\n\t\t\tp(i + 2 * x, i + 2 * x + 1)\n\t\t\tfor j in range(i, 0, -1):\n\t\t\t\tp(j - 1, i + 2 * x + 1)... | {"inputs": ["3\n", "1\n", "5\n", "6\n", "7\n", "8\n", "10\n", "766\n", "555\n", "999\n", "150\n", "899\n", "111\n", "2\n", "22\n", "695\n", "406\n", "219\n", "974\n", "431\n", "186\n", "75\n", "898\n", "731\n", "26\n", "551\n", "310\n", "843\n", "978\n", "319\n", "814\n", "147\n", "58\n", "831\n", "695\n", "766\n", "6\... | VERY_HARD | ['constructive algorithms'] | null | codeforces | ['Constructive algorithms'] | [] | https://codeforces.com/problemset/problem/804/E | null | 2019-12-31 | null | null | null | 25,373 | 0 | n = int(input())
p = lambda a, b: print(a + 1, b + 1)
if n % 4 > 1:
print('NO')
else:
print('YES')
for i in range(n % 4, n, 4):
for x in range(2):
for j in range(i):
p(j, i + 2 * x)
p(i + 2 * x, i + 2 * x + 1)
for j in range(i, 0, -1):
p(j - 1, i + 2 * x + 1)
p(i, i + 3)
p(i + 1, i + 2)
p(i,... | # Question
Seyyed and MoJaK are friends of Sajjad. Sajjad likes a permutation. Seyyed wants to change the permutation in a way that Sajjad won't like it. Seyyed thinks more swaps yield more probability to do that, so he makes MoJaK to perform a swap between every pair of positions (i, j), where i < j, exactly once. Mo... | |
In the final of CODE FESTIVAL in some year, there are N participants. The height and power of Participant i is H_i and P_i, respectively.
Ringo is hosting a game of stacking zabuton (cushions).
The participants will line up in a row in some order, and they will in turn try to add zabuton to the stack of zabuton. Init... | [
"N = int(input())\nmen = []\nfor _ in range(N):\n\t(H, P) = map(int, input().split())\n\tmen.append((H, P, H + P))\nmen.sort(key=lambda x: x[2])\nmaxH = max(men)[0]\ninf = maxH + 1\ndp = [[-1] * (N + 1) for _ in range(N + 1)]\ndp[0][0] = 0\nfor i in range(1, N + 1):\n\t(h, p, a) = men[i - 1]\n\tfor j in range(1, N ... | {"inputs": ["3\n2 4\n3 1\n4 2", "10\n1 3\n8 4\n8 3\n10 1\n6 4\n2 3\n4 2\n9 2\n8 3\n0 1", "3\n0 2\n1 0\n3 4", "10\n1 3\n8 4\n8 3\n10 1\n12 4\n2 3\n4 2\n9 2\n8 3\n0 1", "10\n1 3\n0 4\n15 3\n10 1\n8 4\n2 3\n4 2\n9 1\n8 3\n0 1", "10\n2 3\n0 4\n15 3\n10 1\n8 4\n2 1\n4 2\n9 1\n8 0\n0 1", "10\n2 3\n0 0\n15 3\n10 1\n8 4\n2 1\n... | UNKNOWN_DIFFICULTY | [] | CODE FESTIVAL 2017 Final - Zabuton | atcoder | [] | [] | null | 2.0 seconds | null | null | 256.0 megabytes | null | 25,370 | 0 | N = int(input())
men = []
for _ in range(N):
(H, P) = map(int, input().split())
men.append((H, P, H + P))
men.sort(key=lambda x: x[2])
maxH = max(men)[0]
inf = maxH + 1
dp = [[-1] * (N + 1) for _ in range(N + 1)]
dp[0][0] = 0
for i in range(1, N + 1):
(h, p, a) = men[i - 1]
for j in range(1, N + 1):
if 0 <= dp[i ... | # Question
In the final of CODE FESTIVAL in some year, there are N participants. The height and power of Participant i is H_i and P_i, respectively.
Ringo is hosting a game of stacking zabuton (cushions).
The participants will line up in a row in some order, and they will in turn try to add zabuton to the stack of z... | |
In this Kata, you will be given a multi-dimensional array containing `2 or more` sub-arrays of integers. Your task is to find the maximum product that can be formed by taking any one element from each sub-array.
```
Examples:
solve( [[1, 2],[3, 4]] ) = 8. The max product is given by 2 * 4
solve( [[10,-15],[-1,-3]] ) =... | [
"def solve(arr):\n\t(p, q) = (1, 1)\n\tfor k in arr:\n\t\t(x, y) = (max(k), min(k))\n\t\ta = p * x\n\t\tb = q * x\n\t\tc = p * y\n\t\td = q * y\n\t\tp = max(a, b, c, d)\n\t\tq = min(a, b, c, d)\n\treturn max(p, q)\n",
"def solve(arr):\n\tresult = arr[0]\n\tfor number_array in range(1, len(arr)):\n\t\tresult = [x ... | def solve(arr):
| {"fn_name": "solve", "inputs": [[[[1, 2], [3, 4]]], [[[10, -15], [-1, -3]]], [[[-1, 2, -3, 4], [1, -2, 3, -4]]], [[[-11, -6], [-20, -20], [18, -4], [-20, 1]]], [[[14, 2], [0, -16], [-12, -16]]], [[[-3, -4], [1, 2, -3]]], [[[-2, -15, -12, -8, -16], [-4, -15, -7], [-10, -5]]]], "outputs": [[8], [45], [12], [17600], [3584... | EASY | ['Fundamentals'] | null | codewars | ['Fundamentals'] | [] | https://www.codewars.com/kata/5d0365accfd09600130a00c9 | null | null | null | null | null | 25,374 | 0 | def solve(arr):
(p, q) = (1, 1)
for k in arr:
(x, y) = (max(k), min(k))
a = p * x
b = q * x
c = p * y
d = q * y
p = max(a, b, c, d)
q = min(a, b, c, d)
return max(p, q)
| # Question
In this Kata, you will be given a multi-dimensional array containing `2 or more` sub-arrays of integers. Your task is to find the maximum product that can be formed by taking any one element from each sub-array.
```
Examples:
solve( [[1, 2],[3, 4]] ) = 8. The max product is given by 2 * 4
solve( [[10,-15],... |
Humpy, the little elephant, has his birthday coming up. He invited all his cousins but doesn’t know how many of them are really coming as some of them are having exams coming up. He will only get to know how many of them are coming on the day of his birthday.
He ordered sugarcane for his party, of length L.
Humpy’s m... | [
"from sys import stdin, stdout\nn = int(stdin.readline())\nwhile n:\n\tn -= 1\n\t(k, l, e) = map(int, stdin.readline().strip().split(' '))\n\ta = map(int, stdin.readline().strip().split(' '))\n\tx = float(l) / float(e + sum(a))\n\tif x - int(x):\n\t\tstdout.write('NO\\n')\n\telse:\n\t\tstdout.write('YES\\n')\n",
... | {"inputs": [["2", "4 10 2", "2 2 3 1", "4 12 3", "6 5 7 3"]], "outputs": [["YES", "NO"]]} | UNKNOWN_DIFFICULTY | [] | null | codechef | [] | [] | https://www.codechef.com/IC32016/problems/HBB | null | null | null | null | null | 25,378 | 0 | from sys import stdin, stdout
n = int(stdin.readline())
while n:
n -= 1
(k, l, e) = map(int, stdin.readline().strip().split(' '))
a = map(int, stdin.readline().strip().split(' '))
x = float(l) / float(e + sum(a))
if x - int(x):
stdout.write('NO\n')
else:
stdout.write('YES\n')
| # Question
Humpy, the little elephant, has his birthday coming up. He invited all his cousins but doesn’t know how many of them are really coming as some of them are having exams coming up. He will only get to know how many of them are coming on the day of his birthday.
He ordered sugarcane for his party, of length L... | |
# Introduction
The Condi (Consecutive Digraphs) cipher was introduced by G4EGG (Wilfred Higginson) in 2011. The cipher preserves word divisions, and is simple to describe and encode, but it's surprisingly difficult to crack.
# Encoding Algorithm
The encoding steps are:
- Start with an `initial key`, e.g. `cryptogra... | [
"LOWER = 'abcdefghijklmnopqrstuvwxyz'\n\ndef encode(message, key, shift, encode=True):\n\tkey = sorted(LOWER, key=f'{key}{LOWER}'.index)\n\tresult = []\n\tfor char in message:\n\t\tif char in key:\n\t\t\ti = key.index(char)\n\t\t\tchar = key[(i + shift) % 26]\n\t\t\tshift = i + 1 if encode else -(key.index(char) + ... | def encode(message, key, shift, encode=True):
| {"fn_name": "encode", "inputs": [["on", "cryptogram", 10]], "outputs": [["jx"]]} | EASY | ['Strings', 'Algorithms', 'Ciphers'] | null | codewars | ['String algorithms'] | [] | https://www.codewars.com/kata/59bf6b73bf10a4c8e5000047 | null | null | null | null | null | 25,375 | 0 | LOWER = 'abcdefghijklmnopqrstuvwxyz'
def encode(message, key, shift, encode=True):
key = sorted(LOWER, key=f'{key}{LOWER}'.index)
result = []
for char in message:
if char in key:
i = key.index(char)
char = key[(i + shift) % 26]
shift = i + 1 if encode else -(key.index(char) + 1)
result.append(char)
re... | # Question
# Introduction
The Condi (Consecutive Digraphs) cipher was introduced by G4EGG (Wilfred Higginson) in 2011. The cipher preserves word divisions, and is simple to describe and encode, but it's surprisingly difficult to crack.
# Encoding Algorithm
The encoding steps are:
- Start with an `initial key`, e.g... |
You are given array nums of n length and an integer k .return the maximum number of consecutive 1's in the array if you can flip at most k 0's.
Example:
Input:
n = 11
nums = [1,1,1,0,0,0,1,1,1,1,0]
k = 2
Output:
6
Explanation:
You can flip 2 0 and obtain [1,1,1,0,0,1,1,1,1,1,1]
Your Task:
You don't have to read input ... | [
"class Solution:\n\n\tdef longestOnes(self, n, arr, k):\n\t\t(left, right) = (0, 0)\n\t\tzero_count = 0\n\t\tmaxlen = 0\n\t\twhile right < n:\n\t\t\tif arr[right] == 1:\n\t\t\t\tright += 1\n\t\t\telif zero_count == k:\n\t\t\t\tzero_count -= 1 - arr[left]\n\t\t\t\tleft += 1\n\t\t\telse:\n\t\t\t\tzero_count += 1\n\t\... | #User function Template for python3
class Solution:
def longestOnes(self, n, a, k):
# Code here | {"inputs": ["n = 11\r\nnums = [1,1,1,0,0,0,1,1,1,1,0]\r\nk = 2"], "outputs": ["6"]} | MEDIUM | [] | null | geeksforgeeks | [] | [] | https://practice.geeksforgeeks.org/problems/maximum-consecutive-ones/1 | null | null | 0 | null | O(n) | 25,355 | 0 | class Solution:
def longestOnes(self, n, arr, k):
(left, right) = (0, 0)
zero_count = 0
maxlen = 0
while right < n:
if arr[right] == 1:
right += 1
elif zero_count == k:
zero_count -= 1 - arr[left]
left += 1
else:
zero_count += 1
right += 1
maxlen = max(maxlen, right - left)
r... | # Question
You are given array nums of n length and an integer k .return the maximum number of consecutive 1's in the array if you can flip at most k 0's.
Example:
Input:
n = 11
nums = [1,1,1,0,0,0,1,1,1,1,0]
k = 2
Output:
6
Explanation:
You can flip 2 0 and obtain [1,1,1,0,0,1,1,1,1,1,1]
Your Task:
You don't have to... |
You are given a tree that is built in a following way: initially there is single vertex 1. All the other vertices are added one by one, from vertex 2 to vertex N, by connecting it to one of those that have been added before. You are to find the diameter of the tree after adding each vertex. Let the distance between ver... | [
"def update(M, level, u, v):\n\tlevel[u] = level[v] + 1\n\tM[u][0] = v\n\tfor j in range(1, 18):\n\t\tif M[u][j - 1]:\n\t\t\tM[u][j] = M[M[u][j - 1]][j - 1]\n\ndef LCA(M, level, u, v):\n\tif u == v:\n\t\treturn u\n\tif level[u] < level[v]:\n\t\t(u, v) = (v, u)\n\tfor i in range(17, -1, -1):\n\t\tif M[u][i] and leve... | {"inputs": ["2\n3\n1\n1\n5\n1\n2\n3\n3"], "outputs": ["1\n2\n1\n2\n3\n3"]} | VERY_HARD | ['Algorithms', 'Segment Trees', 'Fenwick Trees', 'Lowest Common Ancestor', 'Advanced Data Structures', 'Graphs', 'Advanced Algorithms', 'Advanced Graph Algos', 'Advanced Tree Structures', 'HLD', 'Data Structures', 'Graph Algos', 'Trees'] | null | codechef | ['Graph algorithms', 'Range queries', 'Segment trees revisited', 'Tree algorithms', 'Data structures', 'Tree queries'] | ['Data structures', 'Range queries'] | https://www.codechef.com/problems/RRTREE | 2 seconds | 2013-09-14 | 0 | 50000 bytes | null | 25,382 | 0 | def update(M, level, u, v):
level[u] = level[v] + 1
M[u][0] = v
for j in range(1, 18):
if M[u][j - 1]:
M[u][j] = M[M[u][j - 1]][j - 1]
def LCA(M, level, u, v):
if u == v:
return u
if level[u] < level[v]:
(u, v) = (v, u)
for i in range(17, -1, -1):
if M[u][i] and level[M[u][i]] >= level[v]:
u = M[u]... | # Question
You are given a tree that is built in a following way: initially there is single vertex 1. All the other vertices are added one by one, from vertex 2 to vertex N, by connecting it to one of those that have been added before. You are to find the diameter of the tree after adding each vertex. Let the distance... | |
Little Artyom decided to study probability theory. He found a book with a lot of nice exercises and now wants you to help him with one of them.
Consider two dices. When thrown each dice shows some integer from 1 to n inclusive. For each dice the probability of each outcome is given (of course, their sum is 1), and dif... | [
"def tle():\n\tk = 0\n\twhile k >= 0:\n\t\tk += 1\n\ndef quad(a, b, c):\n\tdisc = b ** 2 - 4 * a * c\n\tif disc < 0:\n\t\tdisc = 0\n\tdisc = disc ** 0.5\n\treturn ((-b + disc) / 2 / a, (-b - disc) / 2 / a)\nx = int(input())\ny = list(map(float, input().strip().split(' ')))\nz = list(map(float, input().strip().split... | {"inputs": ["2\n0.25 0.75\n0.75 0.25\n", "3\n0.125 0.25 0.625\n0.625 0.25 0.125\n", "10\n0.01 0.01 0.01 0.01 0.01 0.1 0.2 0.2 0.4 0.05\n1.0 0 0 0 0 0 0 0 0 0\n", "10\n0 0 0 0 0 0 0 0 0 1.0\n1.0 0 0 0 0 0 0 0 0 0\n", "1\n1.0\n1.0\n", "2\n0.00001 0.99999\n0.5 0.5\n", "3\n0.1 0.1 0.8\n0.6 0.2 0.2\n", "8\n0.09597231 0.1131... | VERY_HARD | ['probabilities', 'math', 'implementation', 'dp'] | null | codeforces | ['Mathematics', 'Dynamic programming', 'Implementation', 'Probability'] | ['Dynamic programming'] | https://codeforces.com/problemset/problem/641/D | null | 2019-12-31 | null | null | null | 25,384 | 0 | def tle():
k = 0
while k >= 0:
k += 1
def quad(a, b, c):
disc = b ** 2 - 4 * a * c
if disc < 0:
disc = 0
disc = disc ** 0.5
return ((-b + disc) / 2 / a, (-b - disc) / 2 / a)
x = int(input())
y = list(map(float, input().strip().split(' ')))
z = list(map(float, input().strip().split(' ')))
py = [0, y[0]]
for i... | # Question
Little Artyom decided to study probability theory. He found a book with a lot of nice exercises and now wants you to help him with one of them.
Consider two dices. When thrown each dice shows some integer from 1 to n inclusive. For each dice the probability of each outcome is given (of course, their sum is... | |
```if-not:sql
Create a function (or write a script in Shell) that takes an integer as an argument and returns "Even" for even numbers or "Odd" for odd numbers.
```
```if:sql
## SQL Notes:
You will be given a table, `numbers`, with one column `number`.
Return a table with a column `is_even` containing "Even" or "Odd" ... | [
"def even_or_odd(number):\n\treturn 'Odd' if number % 2 else 'Even'\n",
"def even_or_odd(number):\n\treturn ['Even', 'Odd'][number % 2]\n",
"def even_or_odd(number):\n\tstatus = ''\n\tif number % 2 == 0:\n\t\tstatus = 'Even'\n\telse:\n\t\tstatus = 'Odd'\n\treturn status\n",
"def even_or_odd(number):\n\treturn... | def even_or_odd(number):
| {"fn_name": "even_or_odd", "inputs": [[2], [1], [0], [1545452], [7], [78], [17], [74156741], [100000], [-123], [-456]], "outputs": [["Even"], ["Odd"], ["Even"], ["Even"], ["Odd"], ["Even"], ["Odd"], ["Odd"], ["Even"], ["Odd"], ["Even"]]} | EASY | ['Mathematics', 'Fundamentals'] | null | codewars | ['Fundamentals', 'Mathematics'] | [] | https://www.codewars.com/kata/53da3dbb4a5168369a0000fe | null | null | null | null | null | 25,366 | 0 | def even_or_odd(number):
return 'Odd' if number % 2 else 'Even'
| # Question
```if-not:sql
Create a function (or write a script in Shell) that takes an integer as an argument and returns "Even" for even numbers or "Odd" for odd numbers.
```
```if:sql
## SQL Notes:
You will be given a table, `numbers`, with one column `number`.
Return a table with a column `is_even` containing "Eve... |
You are given an array A consisting of N integers.
In one operation, you can:
Choose any two indices i and j (i \neq j);
Subtract min(A_{i} , A_{j}) from both A_{i} and A_{j}. Note that min(A_{i} , A_{j}) denotes the minimum of A_{i} and A_{j}.
Determine whether you can make all the elements of the array equal to zer... | [
"for _ in range(int(input())):\n\tn = int(input())\n\ta = [int(x) for x in input().split()]\n\tassert len(a) == n\n\tassert all((x > 0 for x in a))\n\tsm = sum(a)\n\tif sm % 2 != 0:\n\t\tprint(-1)\n\t\tcontinue\n\tps_sm = {0: []}\n\tfor (i, x) in enumerate(a):\n\t\tps_sm_new = ps_sm.copy()\n\t\tfor (v, indices) in ... | {"inputs": ["3\n2\n1 1 \n3 \n1 3 1\n4\n1 3 1 3\n"], "outputs": ["1\n1 2\n-1\n2\n1 3\n2 4"]} | VERY_HARD | ['Algorithms', 'Dynamic Programming', 'Knapsack'] | null | codechef | ['Dynamic programming'] | ['Dynamic programming'] | https://www.codechef.com/problems/MISREP | 1 seconds | 2023-01-21 | 0 | 50000 bytes | null | 25,388 | 0 | for _ in range(int(input())):
n = int(input())
a = [int(x) for x in input().split()]
assert len(a) == n
assert all((x > 0 for x in a))
sm = sum(a)
if sm % 2 != 0:
print(-1)
continue
ps_sm = {0: []}
for (i, x) in enumerate(a):
ps_sm_new = ps_sm.copy()
for (v, indices) in ps_sm.items():
if v + x not in... | # Question
You are given an array A consisting of N integers.
In one operation, you can:
Choose any two indices i and j (i \neq j);
Subtract min(A_{i} , A_{j}) from both A_{i} and A_{j}. Note that min(A_{i} , A_{j}) denotes the minimum of A_{i} and A_{j}.
Determine whether you can make all the elements of the array ... | |
Ted$Ted$ loves prime numbers. One day he is playing a game called legendary$legendary$ with his girlfriend Robin$Robin$. Ted$Ted$ writes a number N$N$ on a table and the number is in the form of :
N = P1A1 * P2A2 * ……….. * PnAn
Ted$Ted$ asks Robin$Robin$ to find the sum of all the numbers which are less than or equal ... | [
"d = 10 ** 9 + 7\nt = int(input())\nwhile t:\n\tt -= 1\n\tn = int(input())\n\tp = list(map(int, input().strip().split()))\n\ta = list(map(int, input().strip().split()))\n\tb = list(map(int, input().strip().split()))\n\tans = 1\n\tfor i in range(n):\n\t\tc = a[i] - b[i] + 1\n\t\ttmp = pow(p[i], b[i], d) * ((pow(p[i]... | {"inputs": [["1", "3", "2 3 5", "2 1 2", "1 1 1"]], "outputs": [["540"]]} | UNKNOWN_DIFFICULTY | [] | null | codechef | [] | [] | https://www.codechef.com/AARA2018/problems/ARMBH4 | null | null | null | null | null | 25,390 | 0 | d = 10 ** 9 + 7
t = int(input())
while t:
t -= 1
n = int(input())
p = list(map(int, input().strip().split()))
a = list(map(int, input().strip().split()))
b = list(map(int, input().strip().split()))
ans = 1
for i in range(n):
c = a[i] - b[i] + 1
tmp = pow(p[i], b[i], d) * ((pow(p[i], c, d) - 1 + d) % d) * pow... | # Question
Ted$Ted$ loves prime numbers. One day he is playing a game called legendary$legendary$ with his girlfriend Robin$Robin$. Ted$Ted$ writes a number N$N$ on a table and the number is in the form of :
N = P1A1 * P2A2 * ……….. * PnAn
Ted$Ted$ asks Robin$Robin$ to find the sum of all the numbers which are less th... | |
Consider an infinite triangle made up of layers. Let's number the layers, starting from one, from the top of the triangle (from top to bottom). The $k$-th layer of the triangle contains $k$ points, numbered from left to right. Each point of an infinite triangle is described by a pair of numbers $(r, c)$ ($1 \le c \le r... | [
"import os\nimport math\ntrue = True\nfalse = False\nfrom collections import defaultdict, deque, Counter\nfrom functools import reduce\nfrom heapq import *\nis_dev = 'vscode' in os.environ\nif is_dev:\n\tinF = open('in.txt', 'r')\n\toutF = open('out.txt', 'w')\n\ndef ins():\n\treturn list(map(int, input_().split(' ... | {"inputs": ["4\n3\n1 4 2\n1 3 1\n2\n2 4\n2 3\n2\n1 1000000000\n1 1000000000\n4\n3 10 5 8\n2 5 2 4\n", "4\n3\n1 4 2\n1 3 1\n2\n2 4\n2 3\n2\n1 1100000000\n1 1000000000\n4\n3 10 5 8\n2 5 2 4\n", "4\n3\n1 6 2\n1 3 1\n2\n2 4\n2 3\n2\n1 1100000000\n1 1000000000\n4\n3 10 5 8\n2 5 2 4\n", "4\n3\n1 4 2\n1 3 1\n2\n2 7\n2 3\n2\n1... | HARD | ['math', 'shortest paths', 'graphs', 'sortings', 'constructive algorithms'] | null | codeforces | ['Graph algorithms', 'Shortest paths', 'Constructive algorithms', 'Sorting', 'Mathematics'] | ['Sorting'] | https://codeforces.com/problemset/problem/1506/F | 2 seconds | 2021-03-25 | 1 | 256 megabytes | null | 25,357 | 0 | import os
import math
true = True
false = False
from collections import defaultdict, deque, Counter
from functools import reduce
from heapq import *
is_dev = 'vscode' in os.environ
if is_dev:
inF = open('in.txt', 'r')
outF = open('out.txt', 'w')
def ins():
return list(map(int, input_().split(' ')))
def inss():
re... | # Question
Consider an infinite triangle made up of layers. Let's number the layers, starting from one, from the top of the triangle (from top to bottom). The $k$-th layer of the triangle contains $k$ points, numbered from left to right. Each point of an infinite triangle is described by a pair of numbers $(r, c)$ ($1... | |
Given a string s and a string t, check if s is subsequence of t.
You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (
A subsequence of a string is a new string which is formed from the original string by del... | [
"class Solution:\n\n\tdef isSubsequence(self, s, t):\n\t\tif len(s) > len(t):\n\t\t\treturn False\n\t\tfor i in s:\n\t\t\tif i in t:\n\t\t\t\tindex = t.find(i)\n\t\t\t\tt = t[index + 1:]\n\t\t\telse:\n\t\t\t\treturn False\n\t\treturn True\n",
"class Solution:\n\n\tdef isSubsequence(self, s, t):\n\t\ti = 0\n\t\tif... | class Solution:
def isSubsequence(self, s: str, t: str) -> bool:
| {"fn_name": "isSubsequence", "inputs": [["\"abc\"", "\"ahbgdc\""]], "outputs": [true]} | MEDIUM_HARD | ['Two Pointers', 'Dynamic Programming', 'String'] | null | leetcode | ['String algorithms', 'Dynamic programming', 'Amortized analysis'] | ['Dynamic programming', 'Amortized analysis'] | https://leetcode.com/problems/is-subsequence/ | null | null | null | null | null | 25,392 | 0 | class Solution:
def isSubsequence(self, s, t):
if len(s) > len(t):
return False
for i in s:
if i in t:
index = t.find(i)
t = t[index + 1:]
else:
return False
return True
| # Question
Given a string s and a string t, check if s is subsequence of t.
You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (
A subsequence of a string is a new string which is formed from the original s... |
We have N points in the two-dimensional plane. The coordinates of the i-th point are (X_i,Y_i).
Among them, we are looking for the points such that the distance from the origin is at most D. How many such points are there?
We remind you that the distance between the origin and the point (p, q) can be represented as \sq... | [
"def main():\n\t(N, D) = [int(n) for n in input().split(' ')]\n\tcnt = 0\n\tfor i in range(N):\n\t\t(X, Y) = [int(x) for x in input().split(' ')]\n\t\tif X ** 2 + Y ** 2 <= D ** 2:\n\t\t\tcnt += 1\n\tprint(cnt)\nmain()\n",
"(N, D) = map(int, input().split())\nxy = [list(map(int, input().split())) for i in range(N... | {"inputs": ["4 5\n0 5\n-2 4\n3 4\n4 -4\n", "12 3\n1 1\n1 1\n1 1\n1 1\n1 2\n1 3\n2 1\n2 2\n2 3\n3 1\n3 2\n3 3\n", "20 100000\n14309 -32939\n-56855 100340\n151364 25430\n103789 -113141\n147404 -136977\n-37006 -30929\n188810 -49557\n13419 70401\n-88280 165170\n-196399 137941\n-176527 -61904\n46659 115261\n-153551 114185\n... | EASY | [] | null | atcoder | [] | [] | https://atcoder.jp/contests/abc174/tasks/abc174_b | null | null | null | null | null | 25,379 | 0 | def main():
(N, D) = [int(n) for n in input().split(' ')]
cnt = 0
for i in range(N):
(X, Y) = [int(x) for x in input().split(' ')]
if X ** 2 + Y ** 2 <= D ** 2:
cnt += 1
print(cnt)
main()
| # Question
We have N points in the two-dimensional plane. The coordinates of the i-th point are (X_i,Y_i).
Among them, we are looking for the points such that the distance from the origin is at most D. How many such points are there?
We remind you that the distance between the origin and the point (p, q) can be repres... | |
A wildlife study involving ducks is taking place in North America. Researchers are visiting some wetlands in a certain area taking a survey of what they see. The researchers will submit reports that need to be processed by your function.
## Input
The input for your function will be an array with a list of common duc... | [
"def create_report(names):\n\tresult = {}\n\tfor name in names:\n\t\tif name.startswith('Labrador Duck'):\n\t\t\treturn ['Disqualified data']\n\t\tname = name.upper().replace('-', ' ').split()\n\t\tcount = int(name.pop())\n\t\tif len(name) == 1:\n\t\t\tcode = name[0][:6]\n\t\telif len(name) == 2:\n\t\t\tcode = name... | def create_report(names):
| {"fn_name": "create_report", "inputs": [[["Redhead 5", "Labrador Duck 9", "Blue-Winged Teal 25", "Steller's Eider 200"]], [["Canvasback 10", "Mallard 150", "American Wigeon 45", "Baikal Teal 3", "Barrow's Goldeneye 6", "Surf Scoter 12"]], [["Redhead 3", "Gadwall 1", "Smew 4", "Greater Scaup 10", "Redhead 3", "Ga... | EASY | ['Regular Expressions', 'Arrays', 'Fundamentals', 'Data Science'] | null | codewars | ['Fundamentals', 'Data structures'] | ['Data structures'] | https://www.codewars.com/kata/5b0737c724c0686bf8000172 | null | null | null | null | null | 25,393 | 0 | def create_report(names):
result = {}
for name in names:
if name.startswith('Labrador Duck'):
return ['Disqualified data']
name = name.upper().replace('-', ' ').split()
count = int(name.pop())
if len(name) == 1:
code = name[0][:6]
elif len(name) == 2:
code = name[0][:3] + name[1][:3]
elif len(nam... | # Question
A wildlife study involving ducks is taking place in North America. Researchers are visiting some wetlands in a certain area taking a survey of what they see. The researchers will submit reports that need to be processed by your function.
## Input
The input for your function will be an array with a list o... |
The final round of Bayan Programming Contest will be held in Tehran, and the participants will be carried around with a yellow bus. The bus has 34 passenger seats: 4 seats in the last row and 3 seats in remaining rows. [Image]
The event coordinator has a list of k participants who should be picked up at the airport.... | [
"k = int(input())\noutput = ['+------------------------+', '|#.#.#.#.#.#.#.#.#.#.#.|D|)', '|#.#.#.#.#.#.#.#.#.#.#.|.|', '|#.......................|', '|#.#.#.#.#.#.#.#.#.#.#.|.|)', '+------------------------+']\nls = [1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4]... | {"inputs": ["9\n", "20\n", "30\n", "5\n", "0\n", "1\n", "2\n", "3\n", "4\n", "6\n", "7\n", "8\n", "10\n", "11\n", "12\n", "13\n", "14\n", "15\n", "16\n", "17\n", "18\n", "19\n", "21\n", "22\n", "23\n", "24\n", "25\n", "26\n", "27\n", "28\n", "29\n", "31\n", "32\n", "33\n", "34\n", "10\n", "18\n", "0\n", "23\n", "21\n",... | EASY | ['implementation'] | null | codeforces | ['Implementation'] | [] | https://codeforces.com/problemset/problem/475/A | null | 2019-12-31 | null | null | null | 25,356 | 0 | k = int(input())
output = ['+------------------------+', '|#.#.#.#.#.#.#.#.#.#.#.|D|)', '|#.#.#.#.#.#.#.#.#.#.#.|.|', '|#.......................|', '|#.#.#.#.#.#.#.#.#.#.#.|.|)', '+------------------------+']
ls = [1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4, 1, 2, 4]
t = k
... | # Question
The final round of Bayan Programming Contest will be held in Tehran, and the participants will be carried around with a yellow bus. The bus has 34 passenger seats: 4 seats in the last row and 3 seats in remaining rows. [Image]
The event coordinator has a list of k participants who should be picked up at ... | |
You are given a string $s$. You have to reverse it — that is, the first letter should become equal to the last letter before the reversal, the second letter should become equal to the second-to-last letter before the reversal — and so on. For example, if your goal is to reverse the string "abddea", you should get the s... | [
"def mergeSort(arr, n):\n\ttemp_arr = [0] * n\n\treturn _mergeSort(arr, temp_arr, 0, n - 1)\n\ndef _mergeSort(arr, temp_arr, left, right):\n\tinv_count = 0\n\tif left < right:\n\t\tmid = (left + right) // 2\n\t\tinv_count += _mergeSort(arr, temp_arr, left, mid)\n\t\tinv_count += _mergeSort(arr, temp_arr, mid + 1, r... | {"inputs": ["5\naaaza\n", "6\ncbaabc\n", "9\nicpcsguru\n", "50\nfhakqhdhrgfjruxndgfhdvcxhsrjfgdhsyrhfjcbfgdvrtdysf\n", "100\nzzzzzxxxyyyytttttssssssggggdddddjjjjjkkksssssjjjjrdddzzzzxxxxaaaaarrryjjjjddderehhhqazzzzzgdgseryydr\n", "2\ngg\n", "2\nzg\n", "5\nababa\n", "10\ndtottttotd\n", "11\nsssssssssss\n", "100\nrxxxrrx... | HARD | ['data structures', 'greedy', 'strings'] | null | codeforces | ['String algorithms', 'Data structures', 'Greedy algorithms'] | ['Data structures', 'Greedy algorithms'] | https://codeforces.com/problemset/problem/1430/E | 2 seconds | 2020-10-11 | 0 | 256 megabytes | null | 25,362 | 0 | def mergeSort(arr, n):
temp_arr = [0] * n
return _mergeSort(arr, temp_arr, 0, n - 1)
def _mergeSort(arr, temp_arr, left, right):
inv_count = 0
if left < right:
mid = (left + right) // 2
inv_count += _mergeSort(arr, temp_arr, left, mid)
inv_count += _mergeSort(arr, temp_arr, mid + 1, right)
inv_count += mer... | # Question
You are given a string $s$. You have to reverse it — that is, the first letter should become equal to the last letter before the reversal, the second letter should become equal to the second-to-last letter before the reversal — and so on. For example, if your goal is to reverse the string "abddea", you shou... | |
Takahashi received otoshidama (New Year's money gifts) from N of his relatives.
You are given N values x_1, x_2, ..., x_N and N strings u_1, u_2, ..., u_N as input. Each string u_i is either JPY or BTC, and x_i and u_i represent the content of the otoshidama from the i-th relative.
For example, if x_1 = 10000 and u_1 =... | [
"n = int(input())\nbtc = 380000.0\na = 0\nfor _ in range(n):\n\t(x, u) = input().split()\n\tif u == 'JPY':\n\t\ta += int(x)\n\telif u == 'BTC':\n\t\ta += float(x) * btc\nprint(a)\n",
"n = int(input())\nans = 0\nb = 380000\nfor i in range(n):\n\t(x, u) = input().split()\n\tif u == 'JPY':\n\t\tans += int(x)\n\telse... | {"inputs": ["2\n10000 JPY\n0.10000000 BTC\n", "3\n100000000 JPY\n100.00000000 BTC\n0.00000001 BTC\n", "2\n0.00000001 BTC\n0.00000001 BTC\n", "10\n100000000 JPY\n100000000 JPY\n100000000 JPY\n100000000 JPY\n100000000 JPY\n100000000 JPY\n100000000 JPY\n100000000 JPY\n100000000 JPY\n100000000 JPY\n", "10\n100.00000000 BTC... | EASY | [] | AtCoder Beginner Contest 119 - Digital Gifts | atcoder | [] | [] | https://atcoder.jp/contests/abc119/tasks/abc119_b | 2.0 seconds | null | null | 1024.0 megabytes | null | 25,367 | 0 | n = int(input())
btc = 380000.0
a = 0
for _ in range(n):
(x, u) = input().split()
if u == 'JPY':
a += int(x)
elif u == 'BTC':
a += float(x) * btc
print(a)
| # Question
Takahashi received otoshidama (New Year's money gifts) from N of his relatives.
You are given N values x_1, x_2, ..., x_N and N strings u_1, u_2, ..., u_N as input. Each string u_i is either JPY or BTC, and x_i and u_i represent the content of the otoshidama from the i-th relative.
For example, if x_1 = 100... | |
Given an integer array arr and an integer k, modify the array by repeating it k times.
For example, if arr = [1, 2] and k = 3 then the modified array will be [1, 2, 1, 2, 1, 2].
Return the maximum sub-array sum in the modified array. Note that the length of the sub-array can be 0 and its sum in that case is 0.
As the a... | [
"class Solution:\n\n\tdef kConcatenationMaxSum(self, arr: List[int], k: int) -> int:\n\t\toneArrSum = sum(arr)\n\t\ttwoArr = arr + arr\n\n\t\tdef findMaxSub(array):\n\t\t\tif len(array) == 1:\n\t\t\t\treturn array[0]\n\t\t\tcur = 0\n\t\t\tsmall = 0\n\t\t\tret = -999999\n\t\t\tfor i in array:\n\t\t\t\tcur += i\n\t\t... | class Solution:
def kConcatenationMaxSum(self, arr: List[int], k: int) -> int:
| {"fn_name": "kConcatenationMaxSum", "inputs": [[[1, 2], 3]], "outputs": [9]} | MEDIUM | ['Array', 'Dynamic Programming'] | null | leetcode | ['Dynamic programming', 'Data structures'] | ['Dynamic programming', 'Data structures'] | https://leetcode.com/problems/k-concatenation-maximum-sum/ | null | null | null | null | null | 25,391 | 0 | class Solution:
def kConcatenationMaxSum(self, arr: List[int], k: int) -> int:
oneArrSum = sum(arr)
twoArr = arr + arr
def findMaxSub(array):
if len(array) == 1:
return array[0]
cur = 0
small = 0
ret = -999999
for i in array:
cur += i
small = cur if cur < small else small
ret = c... | # Question
Given an integer array arr and an integer k, modify the array by repeating it k times.
For example, if arr = [1, 2] and k = 3 then the modified array will be [1, 2, 1, 2, 1, 2].
Return the maximum sub-array sum in the modified array. Note that the length of the sub-array can be 0 and its sum in that case is... |
There is a one-dimensional garden of length N. In each position of the N length garden, a sprinkler has been installed. Given an array a[]such that a[i] describes the coverage limit of the i^{th} sprinkler. A sprinkler can cover the range from the position max(i - a[i], 1) to min(i + a[i], N). In beginning, all the spr... | [
"class Solution:\n\n\tdef minSprinkler(self, arr, N):\n\t\tcoverages = [-1] * N\n\t\tfor (i, a) in enumerate(arr):\n\t\t\tmin_coverage = max(0, i - a)\n\t\t\tmax_coverage = min(i + a, N - 1)\n\t\t\tcoverages[min_coverage] = max(coverages[min_coverage], max_coverage)\n\t\tneeded_sprinklers_count = 0\n\t\tcurrent_cov... | #User function Template for python3
class Solution():
def minSprinkler(self, arr, N):
#your code goes here | {"inputs": ["a[] = {1, 2, 1}", "a[] = {2, 1, 1, 2, 1}"], "outputs": ["1", "2"]} | MEDIUM_HARD | [] | null | geeksforgeeks | [] | [] | https://practice.geeksforgeeks.org/problems/7645a18a9015b17f754b7a7e1c7d70825dde6acb/1 | null | null | 0 | null | O(N) | 25,397 | 0 | class Solution:
def minSprinkler(self, arr, N):
coverages = [-1] * N
for (i, a) in enumerate(arr):
min_coverage = max(0, i - a)
max_coverage = min(i + a, N - 1)
coverages[min_coverage] = max(coverages[min_coverage], max_coverage)
needed_sprinklers_count = 0
current_coverage = -1
next_max_coverage =... | # Question
There is a one-dimensional garden of length N. In each position of the N length garden, a sprinkler has been installed. Given an array a[]such that a[i] describes the coverage limit of the i^{th} sprinkler. A sprinkler can cover the range from the position max(i - a[i], 1) to min(i + a[i], N). In beginning,... |
You are playing a computer card game called Splay the Sire. Currently you are struggling to defeat the final boss of the game.
The boss battle consists of $n$ turns. During each turn, you will get several cards. Each card has two parameters: its cost $c_i$ and damage $d_i$. You may play some of your cards during each ... | [
"from sys import stdin, stdout, exit\nn = int(input())\ninf = 10 ** 18\ndp = [[-inf] * 10 for i in range(n + 1)]\ndp[0][0] = 0\nfor i in range(n):\n\tk = int(stdin.readline())\n\tcards = []\n\tfor j in range(k):\n\t\t(c, d) = map(int, stdin.readline().split())\n\t\tcards.append((c, d))\n\tcards.sort(reverse=True)\n... | {"inputs": ["5\n3\n1 6\n1 7\n1 5\n2\n1 4\n1 3\n3\n1 10\n3 5\n2 3\n3\n1 15\n2 4\n1 10\n1\n1 100\n", "5\n3\n1 1\n1 1\n1 1\n3\n1 1\n1 1\n1 1\n3\n1 1\n1 1\n1 1\n3\n1 1\n1 1\n1 1\n3\n1 100\n1 1\n1 1\n", "1\n4\n1 1\n1 1\n2 2\n3 4\n", "5\n3\n1 1\n1 1\n1 1\n3\n1 1\n1 1\n1 1\n3\n1 1\n1 1\n1 1\n3\n1 1\n1 1\n1 1\n3\n1 100\n1 1\n1... | HARD | ['sortings', 'implementation', 'dp'] | null | codeforces | ['Dynamic programming', 'Sorting', 'Implementation'] | ['Dynamic programming', 'Sorting'] | https://codeforces.com/problemset/problem/1176/F | null | 2019-12-31 | null | null | null | 25,401 | 0 | from sys import stdin, stdout, exit
n = int(input())
inf = 10 ** 18
dp = [[-inf] * 10 for i in range(n + 1)]
dp[0][0] = 0
for i in range(n):
k = int(stdin.readline())
cards = []
for j in range(k):
(c, d) = map(int, stdin.readline().split())
cards.append((c, d))
cards.sort(reverse=True)
cards_by_cost = [[] for ... | # Question
You are playing a computer card game called Splay the Sire. Currently you are struggling to defeat the final boss of the game.
The boss battle consists of $n$ turns. During each turn, you will get several cards. Each card has two parameters: its cost $c_i$ and damage $d_i$. You may play some of your cards ... | |
Singh is getting bored at work. He has a lot of ideas (N) to work on (as side projects) but is unable to choose one.
He chooses a random number (R) and lines up his ideas in a circle. He starts counting from first and removes the R^th idea in the circle until only one remains. Help him choose an idea to work on.
Inpu... | [
"N, R = [int(i) for i in input().split()]\n\nr = 0\nfor i in range(1, N+1):\n\tr = (r+R)%i\nprint(r+1)\n",
"n,r = list(map(int, input().split()))\nm,j = n,0\nr -= 1\ntmp = [i+1 for i in range(n)]\nfor i in range(n):\n\tj = (j+r)%m\n\tans = tmp[j]\n\ttmp = tmp[:j]+tmp[j+1:]\n\tm -= 1\t\nprint(ans)\n",
"n,k=list(... | {"inputs": ["23 9000001", "23 9000000"], "outputs": ["6", "4"]} | UNKNOWN_DIFFICULTY | [] | to-be-changed-choosing-a-project | hackerearth | [] | [] | null | null | null | null | null | null | 25,412 | 0 | N, R = [int(i) for i in input().split()]
r = 0
for i in range(1, N+1):
r = (r+R)%i
print(r+1)
| # Question
Singh is getting bored at work. He has a lot of ideas (N) to work on (as side projects) but is unable to choose one.
He chooses a random number (R) and lines up his ideas in a circle. He starts counting from first and removes the R^th idea in the circle until only one remains. Help him choose an idea to wo... | |
Given a triangle of consecutive odd numbers:
```
1
3 5
7 9 11
13 15 17 19
21 23 25 27 29
...
```
find the triangle's row knowing its index (the rows are 1-indexed), e.g.:
```
odd_row(1) == [1]
odd_row(2) == [3, 5]
odd_row(3) == [7, 9, 11]
```
**... | [
"odd_row = lambda n: list(range(n * (n - 1) + 1, n * (n + 1), 2))\n",
"def odd_row(n):\n\tm = (n - 1) * n + 1\n\treturn [*range(m, m + n * 2, 2)]\n",
"def odd_row(n):\n\treturn [x for x in range(n ** 2 - n + 1, (n + 1) ** 2 - n, 2)]\n",
"def odd_row(n):\n\treturn [x for x in range(n * n - n, n * n + n) if x %... | def odd_row(n):
| {"fn_name": "odd_row", "inputs": [[1], [2], [13], [19], [41], [93]], "outputs": [[[1]], [[3, 5]], [[157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181]], [[343, 345, 347, 349, 351, 353, 355, 357, 359, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379]], [[1641, 1643, 1645, 1647, 1649, 1651, 1653, 1655, 1657... | EASY | ['Performance', 'Algorithms'] | null | codewars | [] | [] | https://www.codewars.com/kata/5d5a7525207a674b71aa25b5 | null | null | null | null | null | 25,405 | 0 | odd_row = lambda n: list(range(n * (n - 1) + 1, n * (n + 1), 2))
| # Question
Given a triangle of consecutive odd numbers:
```
1
3 5
7 9 11
13 15 17 19
21 23 25 27 29
...
```
find the triangle's row knowing its index (the rows are 1-indexed), e.g.:
```
odd_row(1) == [1]
odd_row(2) == [3, 5]
odd_row(3) == [7, 9,... |
The chef is trying to solve some pattern problems, Chef wants your help to code it. Chef has one number K to form a new pattern. Help the chef to code this pattern problem.
-----Input:-----
- First-line will contain $T$, the number of test cases. Then the test cases follow.
- Each test case contains a single line of ... | [
"t = int(input())\nfor _ in range(t):\n\tk = int(input())\n\tcount = 1\n\tfor _ in range(k):\n\t\toutput = []\n\t\tfor index in range(1, k + 1):\n\t\t\toutput.append(bin(count).replace('0b', ''))\n\t\t\tcount += 1\n\t\tprint(*output)\n",
"for _ in range(int(input())):\n\tk = int(input())\n\tx = 1\n\tfor i in rang... | {"inputs": [["4", "1", "2", "3", "4"]], "outputs": [["1", "1 10", "11 100", "1 10 11", "100 101 110", "111 1000 1001", "1 10 11 100", "101 110 111 1000", "1001 1010 1011 1100", "1101 1110 1111 10000"]]} | UNKNOWN_DIFFICULTY | [] | null | codechef | [] | [] | https://www.codechef.com/PTRN2021/problems/ITGUY52 | null | null | null | null | null | 25,402 | 0 | t = int(input())
for _ in range(t):
k = int(input())
count = 1
for _ in range(k):
output = []
for index in range(1, k + 1):
output.append(bin(count).replace('0b', ''))
count += 1
print(*output)
| # Question
The chef is trying to solve some pattern problems, Chef wants your help to code it. Chef has one number K to form a new pattern. Help the chef to code this pattern problem.
-----Input:-----
- First-line will contain $T$, the number of test cases. Then the test cases follow.
- Each test case contains a sin... | |
Read problems statements in Mandarin Chinese and Russian.
This summer, there is a worldwide competition being held in Chef Town and some of the best chefs of the world are participating. The rules of this competition are quite simple.
Each participant needs to bring his or her best dish. The judges will initially ... | [
"def find(child):\n\tnew_parent = child\n\twhile new_parent != parents[new_parent]:\n\t\tnew_parent = parents[new_parent]\n\twhile child != parents[child]:\n\t\ttemp = parents[child]\n\t\tparents[child] = new_parent\n\t\tchild = temp\n\treturn new_parent\n\ndef union(root1, root2):\n\t(real_root1, real_root2) = (fi... | {"inputs": ["1\n2\n1 2\n2\n0 1 2\n1 1", "1\n2\n1 3\n2\n0 1 2\n1 1", "1\n2\n1 1\n2\n0 1 2\n1 1", "1\n2\n1 3\n2\n0 1 1\n1 1", "1\n2\n0 1\n2\n0 2 2\n1 0", "1\n4\n0 1\n2\n0 2 2\n1 0", "1\n2\n0 1\n1\n0 1 1\n1 0", "1\n3\n0 1\n2\n0 1 2\n1 0", "1\n6\n0 1\n2\n0 1 2\n1 0", "1\n4\n0 1\n2\n0 1 2\n1 0", "1\n3\n0 1\n2\n0 1 1\n1 0", ... | MEDIUM_HARD | ['Advanced Data Structures', 'Disjoint Set Union'] | null | codechef | ['Spanning trees', 'Data structures'] | ['Data structures'] | https://www.codechef.com/problems/DISHOWN | 0.5 seconds | 2014-04-25 | 0 | 50000 bytes | null | 25,399 | 0 | def find(child):
new_parent = child
while new_parent != parents[new_parent]:
new_parent = parents[new_parent]
while child != parents[child]:
temp = parents[child]
parents[child] = new_parent
child = temp
return new_parent
def union(root1, root2):
(real_root1, real_root2) = (find(root1), find(root2))
if r... | # Question
Read problems statements in Mandarin Chinese and Russian.
This summer, there is a worldwide competition being held in Chef Town and some of the best chefs of the world are participating. The rules of this competition are quite simple.
Each participant needs to bring his or her best dish. The judges wil... | |
Chef lives in a big apartment in Chefland. The apartment charges maintenance fees that he is supposed to pay monthly on time. But Chef is a lazy person and sometimes misses the deadlines. The apartment charges 1000 Rs per month as maintenance fees. Also, they also charge a one-time fine of 100 Rs for each of the late p... | [
"for i in range(int(input())):\n\tn = int(input())\n\tp = list(map(int, input().split()))\n\tamount = p.count(0) * 1000\n\tif p.count(0) != 0:\n\t\tq = p.index(0)\n\t\tprint(100 * (n - q) + amount)\n\telse:\n\t\tprint(amount)\n",
"for _ in range(int(input())):\n\tn = int(input())\n\tl = list(map(int, input().spli... | {"inputs": [["4", "2", "1 1", "2", "0 0", "3", "0 1 0", "2", "0 1", "", ""]], "outputs": [["0", "2200", "2300", "1200"]]} | EASY | ['Mathematics', 'Basic Maths'] | null | codechef | ['Mathematics'] | [] | https://www.codechef.com/problems/CHEFAPAR | 2 seconds | 2017-02-01 | 0 | 50000 bytes | null | 25,407 | 0 | for i in range(int(input())):
n = int(input())
p = list(map(int, input().split()))
amount = p.count(0) * 1000
if p.count(0) != 0:
q = p.index(0)
print(100 * (n - q) + amount)
else:
print(amount)
| # Question
Chef lives in a big apartment in Chefland. The apartment charges maintenance fees that he is supposed to pay monthly on time. But Chef is a lazy person and sometimes misses the deadlines. The apartment charges 1000 Rs per month as maintenance fees. Also, they also charge a one-time fine of 100 Rs for each o... | |
Juggler Sequence is a series of integers in which the first term starts with a positive integer number a and the remaining terms are generated from the immediate previous term using the below recurrence relation:
Given a number N, find the Juggler Sequence for this number as the first term of the sequence.
Example 1:
I... | [
"import math\n\nclass Solution:\n\n\tdef jugglerSequence(self, N):\n\t\tif N == 1:\n\t\t\treturn [1]\n\t\tseq = [N]\n\t\tif N % 2 == 0:\n\t\t\tseq.extend(self.jugglerSequence(int(N ** 0.5)))\n\t\telse:\n\t\t\tseq.extend(self.jugglerSequence(int(N ** 1.5)))\n\t\treturn seq\n",
"class Solution:\n\n\tdef jugglerSequ... | #User function Template for python3
class Solution:
def jugglerSequence(self, N):
# code here | {"inputs": ["N = 9", "N = 6"], "outputs": ["9 27 140 11 36 6 2 1", " 6 2 1"]} | EASY | ['Recursion', 'Algorithms', 'Mathematical', 'series'] | null | geeksforgeeks | ['Mathematics', 'Complete search'] | ['Complete search'] | https://practice.geeksforgeeks.org/problems/juggler-sequence3930/1 | null | null | 1 | null | O(N) | 25,398 | 0 | import math
class Solution:
def jugglerSequence(self, N):
if N == 1:
return [1]
seq = [N]
if N % 2 == 0:
seq.extend(self.jugglerSequence(int(N ** 0.5)))
else:
seq.extend(self.jugglerSequence(int(N ** 1.5)))
return seq
| # Question
Juggler Sequence is a series of integers in which the first term starts with a positive integer number a and the remaining terms are generated from the immediate previous term using the below recurrence relation:
Given a number N, find the Juggler Sequence for this number as the first term of the sequence.
... |
Polycarp has a checkered sheet of paper of size n × m. Polycarp painted some of cells with black, the others remained white. Inspired by Malevich's "Black Square", Polycarp wants to paint minimum possible number of white cells with black so that all black cells form a square.
You are to determine the minimum possible ... | [
"def min_squares(canvas, length, width):\n\n\tdef find_top():\n\t\tfor i in range(length):\n\t\t\tfor j in range(width):\n\t\t\t\tif canvas[i][j] == 'B':\n\t\t\t\t\treturn i\n\t\treturn -1\n\n\tdef find_left():\n\t\tfor j in range(width):\n\t\t\tfor i in range(length):\n\t\t\t\tif canvas[i][j] == 'B':\n\t\t\t\t\tre... | {"inputs": ["5 4\nWWWW\nWWWB\nWWWB\nWWBB\nWWWW\n", "1 2\nBB\n", "3 3\nWWW\nWWW\nWWW\n", "100 1\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nB\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\nW\... | EASY | ['implementation'] | null | codeforces | ['Implementation'] | [] | https://codeforces.com/problemset/problem/828/B | null | 2019-12-31 | null | null | null | 25,395 | 0 | def min_squares(canvas, length, width):
def find_top():
for i in range(length):
for j in range(width):
if canvas[i][j] == 'B':
return i
return -1
def find_left():
for j in range(width):
for i in range(length):
if canvas[i][j] == 'B':
return j
def find_bottom():
for i in reversed(ra... | # Question
Polycarp has a checkered sheet of paper of size n × m. Polycarp painted some of cells with black, the others remained white. Inspired by Malevich's "Black Square", Polycarp wants to paint minimum possible number of white cells with black so that all black cells form a square.
You are to determine the minim... | |
Sereja is a coder and he likes to take part in Codesorfes rounds. However, Uzhland doesn't have good internet connection, so Sereja sometimes skips rounds.
Codesorfes has rounds of two types: Div1 (for advanced coders) and Div2 (for beginner coders). Two rounds, Div1 and Div2, can go simultaneously, (Div1 round cannot... | [
"(X, n) = list(map(int, input().split()))\nTaken = [True] * (X + 1)\nfor i in range(n):\n\tx = list(map(int, input().split()))\n\tif x[0] == 1:\n\t\tTaken[x[1]] = False\n\t\tTaken[x[2]] = False\n\telse:\n\t\tTaken[x[1]] = False\ncnt = 0\nminn = 0\nmaxx = 0\nans = 0\nfor i in range(1, X):\n\tif Taken[i]:\n\t\tcnt +=... | {"inputs": ["3 2\n2 1\n2 2\n", "9 3\n1 2 3\n2 8\n1 4 5\n", "10 0\n", "10 2\n1 1 2\n1 8 9\n", "9 3\n1 4 5\n1 1 2\n1 6 7\n", "7 2\n2 3\n1 5 6\n", "81 28\n1 77 78\n1 50 51\n2 9\n1 66 67\n1 12 13\n1 20 21\n1 28 29\n1 34 35\n1 54 55\n2 19\n1 70 71\n1 45 46\n1 36 37\n2 47\n2 7\n2 76\n2 6\n2 31\n1 16 17\n1 4 5\n1 73 74\n1 64 ... | EASY | ['greedy', 'math', 'implementation'] | null | codeforces | ['Mathematics', 'Implementation', 'Greedy algorithms'] | ['Greedy algorithms'] | https://codeforces.com/problemset/problem/401/B | null | 2019-12-31 | null | null | null | 25,406 | 0 | (X, n) = list(map(int, input().split()))
Taken = [True] * (X + 1)
for i in range(n):
x = list(map(int, input().split()))
if x[0] == 1:
Taken[x[1]] = False
Taken[x[2]] = False
else:
Taken[x[1]] = False
cnt = 0
minn = 0
maxx = 0
ans = 0
for i in range(1, X):
if Taken[i]:
cnt += 1
maxx += 1
else:
ans += c... | # Question
Sereja is a coder and he likes to take part in Codesorfes rounds. However, Uzhland doesn't have good internet connection, so Sereja sometimes skips rounds.
Codesorfes has rounds of two types: Div1 (for advanced coders) and Div2 (for beginner coders). Two rounds, Div1 and Div2, can go simultaneously, (Div1 ... | |
Return the number of distinct non-empty substrings of text that can be written as the concatenation of some string with itself (i.e. it can be written as a + a where a is some string).
Example 1:
Input: text = "abcabcabc"
Output: 3
Explanation: The 3 substrings are "abcabc", "bcabca" and "cabcab".
Example 2:
Input: ... | [
"from collections import defaultdict, deque\n\nclass Solution:\n\n\tdef distinctEchoSubstrings(self, text: str) -> int:\n\t\tif all((x == text[0] for x in text)):\n\t\t\treturn len(text) // 2\n\t\tres = set()\n\t\tcharacter_locations = defaultdict(lambda : deque())\n\t\tfor (i, c) in enumerate(text):\n\t\t\tfor j i... | class Solution:
def distinctEchoSubstrings(self, text: str) -> int:
| {"fn_name": "distinctEchoSubstrings", "inputs": [["\"abcabcabc\""]], "outputs": [3]} | MEDIUM | ['Trie', 'Hash Function', 'Rolling Hash', 'String'] | null | leetcode | ['String algorithms'] | [] | https://leetcode.com/problems/distinct-echo-substrings/ | null | null | null | null | null | 25,404 | 0 | from collections import defaultdict, deque
class Solution:
def distinctEchoSubstrings(self, text: str) -> int:
if all((x == text[0] for x in text)):
return len(text) // 2
res = set()
character_locations = defaultdict(lambda : deque())
for (i, c) in enumerate(text):
for j in character_locations[c]:
... | # Question
Return the number of distinct non-empty substrings of text that can be written as the concatenation of some string with itself (i.e. it can be written as a + a where a is some string).
Example 1:
Input: text = "abcabcabc"
Output: 3
Explanation: The 3 substrings are "abcabc", "bcabca" and "cabcab".
Exampl... |
There is a tree with N vertices, numbered 1 through N. The i-th edge in this tree connects Vertices A_i and B_i and has a length of C_i.
Joisino created a complete graph with N vertices. The length of the edge connecting Vertices u and v in this graph, is equal to the shortest distance between Vertices u and v in the ... | [
"import sys\ninput = sys.stdin.readline\nfrom collections import defaultdict\nn = int(input())\nabd = [list(map(int, input().split())) for i in range(n - 1)]\nif n == 2:\n\tprint(abd[0][2])\n\texit()\ngraph = [[] for i in range(n + 1)]\ndeg = [0 for i in range(n + 1)]\nfor (a, b, d) in abd:\n\tgraph[a].append((b, d... | {"inputs": ["8\n2 8 8\n1 5 1\n4 8 2\n2 5 4\n3 8 5\n6 8 9\n2 7 12", "5\n1 2 5\n3 4 10\n2 3 3\n2 5 2", "5\n1 3 5\n3 4 10\n2 3 3\n2 5 2", "5\n1 3 5\n2 4 20\n2 3 3\n2 5 2", "8\n2 8 8\n1 5 1\n4 8 2\n2 5 7\n3 8 6\n6 8 9\n2 7 12", "8\n2 8 8\n1 5 1\n4 8 0\n2 5 4\n3 8 5\n6 8 9\n2 7 12", "5\n1 3 4\n2 4 10\n2 3 3\n2 5 2", "8\n2 4... | UNKNOWN_DIFFICULTY | [] | AtCoder Grand Contest 018 - Tree and Hamilton Path | atcoder | [] | [] | null | 2.0 seconds | null | null | 256.0 megabytes | null | 25,403 | 0 | import sys
input = sys.stdin.readline
from collections import defaultdict
n = int(input())
abd = [list(map(int, input().split())) for i in range(n - 1)]
if n == 2:
print(abd[0][2])
exit()
graph = [[] for i in range(n + 1)]
deg = [0 for i in range(n + 1)]
for (a, b, d) in abd:
graph[a].append((b, d))
graph[b].append... | # Question
There is a tree with N vertices, numbered 1 through N. The i-th edge in this tree connects Vertices A_i and B_i and has a length of C_i.
Joisino created a complete graph with N vertices. The length of the edge connecting Vertices u and v in this graph, is equal to the shortest distance between Vertices u a... | |
You are given $\textit{q}$ queries where each query consists of a set of $n$ points on a two-dimensional plane (i.e., $(x,y)$). For each set of points, print YES on a new line if all the points fall on the edges (i.e., sides and/or corners) of a non-degenerate rectangle which is axis parallel; otherwise, print NO inste... | [
"def main():\n\tfor i in range(int(input())):\n\t\tp = [list(map(int, input().split())) for j in range(int(input()))]\n\t\t(px, py) = zip(*p)\n\t\tx0 = min(px)\n\t\tx1 = max(px)\n\t\ty0 = min(py)\n\t\ty1 = max(py)\n\t\tresult = all((x in (x0, x1) or y in (y0, y1) for (x, y) in p))\n\t\tprint('YES' if result else 'N... | {"inputs": ["2\n3\n0 0\n0 1\n1 0\n4\n0 0\n0 2\n2 0\n1 1\n"], "outputs": ["YES\nNO\n"]} | EASY | ['Mathematics - Geometry'] | null | hackerrank | ['Geometry'] | [] | https://www.hackerrank.com/challenges/points-on-rectangle/problem | null | null | 0 | null | null | 25,410 | 0 | def main():
for i in range(int(input())):
p = [list(map(int, input().split())) for j in range(int(input()))]
(px, py) = zip(*p)
x0 = min(px)
x1 = max(px)
y0 = min(py)
y1 = max(py)
result = all((x in (x0, x1) or y in (y0, y1) for (x, y) in p))
print('YES' if result else 'NO')
main()
| # Question
You are given $\textit{q}$ queries where each query consists of a set of $n$ points on a two-dimensional plane (i.e., $(x,y)$). For each set of points, print YES on a new line if all the points fall on the edges (i.e., sides and/or corners) of a non-degenerate rectangle which is axis parallel; otherwise, pr... | |
Given a binary heap implementation of Priority Queue. Extract the maximum element from the queue i.e. remove it from the Queue and return it's value.
Example 1:
Input: 4 2 8 16 24 2 6 5
Output: 24
Priority Queue after extracting maximum: 16 8 6 5 2 2 4
Example 2:
Input: 64 12 8 48 5
Output: 64
Priority Queue after e... | [
"class Solution:\n\n\tdef extractMax(self):\n\t\tglobal s\n\t\tans = H[0]\n\t\tH[0] = H[s]\n\t\ts -= 1\n\t\tshiftDown(0)\n\t\treturn ans\n"
] | #User function Template for python3
# 1. parent(i): Function to return the parent node of node i
# 2. leftChild(i): Function to return index of the left child of node i
# 3. rightChild(i): Function to return index of the right child of node i
# 4. shiftUp(int i): Function to shift up the node in order to maintain... | {"inputs": ["4 2 8 16 24 2 6 5", "64 12 8 48 5"], "outputs": ["24", "64"]} | MEDIUM | [] | null | geeksforgeeks | [] | [] | https://practice.geeksforgeeks.org/problems/implementation-of-priority-queue-using-binary-heap/1 | null | null | 0 | null | O(logN) | 25,417 | 0 | class Solution:
def extractMax(self):
global s
ans = H[0]
H[0] = H[s]
s -= 1
shiftDown(0)
return ans
| # Question
Given a binary heap implementation of Priority Queue. Extract the maximum element from the queue i.e. remove it from the Queue and return it's value.
Example 1:
Input: 4 2 8 16 24 2 6 5
Output: 24
Priority Queue after extracting maximum: 16 8 6 5 2 2 4
Example 2:
Input: 64 12 8 48 5
Output: 64
Priority Q... |
Rachel, being an awesome android programmer, just finished an App that will let us draw a triangle by selecting three points on the touch-plane.Now She asks her friend Bruce to draw a Right-Angled Triangle (we'll call it RAT) by selecting 3 integral points on the plane.
A RAT is a triangle with Non-Zero area and a rig... | [
"def dist(x1,y1,x2,y2):\n\treturn (x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)\n\ndef is_RAT(a):\n\tab = dist(a[0],a[1],a[2],a[3])\n\tbc = dist(a[4],a[5],a[2],a[3])\n\tca = dist(a[0],a[1],a[4],a[5])\n\tif ab == bc+ca or ca == bc+ab or bc == ab+ca:\n\t\treturn True\n\treturn False\t\ndef samepoint(a):\n\tif a[0]==a[2] and a[1] =... | {"inputs": ["20\n0 0 1 0 4 1\n0 0 1 0 100 1\n60 4 90 -53 32 -12\n52 -34 -37 -63 23 54\n39 22 95 25 42 -33\n-10 -11 62 6 -12 -3\n22 -15 -24 77 -69 -60\n99 85 90 87 64 -20\n-50 -37 -93 -6 -80 -80\n4 -13 4 -49 -24 -13\n0 -3 -3 -10 4 -7\n-45 -87 -34 -79 -60 -62\n-67 49 89 -76 -37 87\n22 32 -33 -30 -18 68\n36 1 -17 -54 -19 ... | UNKNOWN_DIFFICULTY | [] | autocorrect | hackerearth | [] | [] | null | null | null | null | null | null | 25,415 | 0 | def dist(x1,y1,x2,y2):
return (x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)
def is_RAT(a):
ab = dist(a[0],a[1],a[2],a[3])
bc = dist(a[4],a[5],a[2],a[3])
ca = dist(a[0],a[1],a[4],a[5])
if ab == bc+ca or ca == bc+ab or bc == ab+ca:
return True
return False
def samepoint(a):
if a[0]==a[2] and a[1] == a[3]:
return True
if ... | # Question
Rachel, being an awesome android programmer, just finished an App that will let us draw a triangle by selecting three points on the touch-plane.Now She asks her friend Bruce to draw a Right-Angled Triangle (we'll call it RAT) by selecting 3 integral points on the plane.
A RAT is a triangle with Non-Zero ar... | |
You are given an array a consisting of n positive integers. You pick two integer numbers l and r from 1 to n, inclusive (numbers are picked randomly, equiprobably and independently). If l > r, then you swap values of l and r. You have to calculate the expected value of the number of unique elements in segment of the ar... | [
"n = int(input())\narr = [0]\narr = arr + list(map(int, input().split(' ')))\n\ndef getCounts(arr):\n\tlast = {}\n\tans = 0.0\n\tprev = 0.0\n\tres = 0.0\n\tfor i in range(1, len(arr)):\n\t\tif arr[i] not in last:\n\t\t\tans = prev + i\n\t\telse:\n\t\t\tans = prev + i - last[arr[i]]\n\t\tprev = ans\n\t\tres += ans\n... | {"inputs": ["2\n1 2\n", "2\n2 2\n", "10\n9 6 8 5 5 2 8 9 2 2\n", "20\n49 33 9 8 50 21 12 44 23 39 24 10 17 4 17 40 24 19 27 21\n", "1\n1000000\n", "10\n9 6 8 5 5 2 8 9 2 2\n", "20\n49 33 9 8 50 21 12 44 23 39 24 10 17 4 17 40 24 19 27 21\n", "1\n1000000\n", "10\n9 6 8 5 5 2 8 9 2 1\n", "20\n49 33 9 8 50 21 12 44 23 39 ... | MEDIUM_HARD | ['two pointers', 'data structures', 'probabilities', 'math'] | null | codeforces | ['Data structures', 'Amortized analysis', 'Mathematics', 'Probability'] | ['Amortized analysis', 'Data structures'] | https://codeforces.com/problemset/problem/846/F | null | 2019-12-31 | null | null | null | 25,414 | 0 | n = int(input())
arr = [0]
arr = arr + list(map(int, input().split(' ')))
def getCounts(arr):
last = {}
ans = 0.0
prev = 0.0
res = 0.0
for i in range(1, len(arr)):
if arr[i] not in last:
ans = prev + i
else:
ans = prev + i - last[arr[i]]
prev = ans
res += ans
last[arr[i]] = i
return res
ans = (2 ... | # Question
You are given an array a consisting of n positive integers. You pick two integer numbers l and r from 1 to n, inclusive (numbers are picked randomly, equiprobably and independently). If l > r, then you swap values of l and r. You have to calculate the expected value of the number of unique elements in segme... | |
Natasha's favourite numbers are $n$ and $1$, and Sasha's favourite numbers are $m$ and $-1$. One day Natasha and Sasha met and wrote down every possible array of length $n+m$ such that some $n$ of its elements are equal to $1$ and another $m$ elements are equal to $-1$. For each such array they counted its maximal pref... | [
"P = 998244853\nN = 4000\n(f, fi) = ([0] * (N + 1), [0] * (N + 1))\nf[0] = 1\nfor i in range(N):\n\tf[i + 1] = f[i] * (i + 1) % P\nfi[-1] = pow(f[-1], P - 2, P)\nfor i in reversed(range(N)):\n\tfi[i] = fi[i + 1] * (i + 1) % P\n\ndef C(n, r):\n\tc = 1\n\twhile n or r:\n\t\t(a, b) = (n % P, r % P)\n\t\tif a < b:\n\t\... | {"inputs": ["0 2\n", "2 0\n", "2 2\n", "2000 2000\n", "0 0\n", "11 2\n", "1 4\n", "5 13\n", "60 59\n", "27 16\n", "1134 1092\n", "756 1061\n", "953 1797\n", "76 850\n", "24 1508\n", "1087 1050\n", "149 821\n", "983 666\n", "45 1323\n", "1994 1981\n", "1942 1523\n", "1891 1294\n", "1132 1727\n", "1080 383\n", "1028 1040... | HARD | ['number theory', 'combinatorics', 'math', 'dp'] | null | codeforces | ['Number theory', 'Combinatorics', 'Dynamic programming', 'Mathematics'] | ['Dynamic programming'] | https://codeforces.com/problemset/problem/1204/E | null | 2019-12-31 | null | null | null | 25,418 | 0 | P = 998244853
N = 4000
(f, fi) = ([0] * (N + 1), [0] * (N + 1))
f[0] = 1
for i in range(N):
f[i + 1] = f[i] * (i + 1) % P
fi[-1] = pow(f[-1], P - 2, P)
for i in reversed(range(N)):
fi[i] = fi[i + 1] * (i + 1) % P
def C(n, r):
c = 1
while n or r:
(a, b) = (n % P, r % P)
if a < b:
return 0
c = c * f[a] % P ... | # Question
Natasha's favourite numbers are $n$ and $1$, and Sasha's favourite numbers are $m$ and $-1$. One day Natasha and Sasha met and wrote down every possible array of length $n+m$ such that some $n$ of its elements are equal to $1$ and another $m$ elements are equal to $-1$. For each such array they counted its ... | |
Amr bought a new video game "Guess Your Way Out!". The goal of the game is to find an exit from the maze that looks like a perfect binary tree of height h. The player is initially standing at the root of the tree and the exit from the tree is located at some leaf node.
Let's index all the leaf nodes from the left to ... | [
"import sys\nimport math\nMAXNUM = math.inf\nMINNUM = -1 * math.inf\nASCIILOWER = 97\nASCIIUPPER = 65\n\ndef getInt():\n\treturn int(sys.stdin.readline().rstrip())\n\ndef getInts():\n\treturn map(int, sys.stdin.readline().rstrip().split(' '))\n\ndef getString():\n\treturn sys.stdin.readline().rstrip()\n\ndef printO... | {"inputs": ["1 2\n", "2 3\n", "3 6\n", "10 1024\n", "10 577\n", "11 550\n", "19 12783\n", "28 72803174\n", "39 457181784666\n", "12 955\n", "13 154\n", "14 2334\n", "15 15512\n", "16 21395\n", "17 80239\n", "18 153276\n", "20 589266\n", "21 1687606\n", "24 14428281\n", "29 113463931\n", "1 1\n", "3 8\n", "31 1819651953... | MEDIUM_HARD | ['trees', 'math', 'implementation'] | null | codeforces | ['Mathematics', 'Tree algorithms', 'Implementation'] | [] | https://codeforces.com/problemset/problem/507/C | null | 2019-12-31 | null | null | null | 25,400 | 0 | import sys
import math
MAXNUM = math.inf
MINNUM = -1 * math.inf
ASCIILOWER = 97
ASCIIUPPER = 65
def getInt():
return int(sys.stdin.readline().rstrip())
def getInts():
return map(int, sys.stdin.readline().rstrip().split(' '))
def getString():
return sys.stdin.readline().rstrip()
def printOutput(ans):
sys.stdout.... | # Question
Amr bought a new video game "Guess Your Way Out!". The goal of the game is to find an exit from the maze that looks like a perfect binary tree of height h. The player is initially standing at the root of the tree and the exit from the tree is located at some leaf node.
Let's index all the leaf nodes from ... | |
Write a program which reads the two dices constructed in the same way as Dice I, and determines whether these two dices are identical. You can roll a dice in the same way as Dice I, and if all integers observed from the six directions are the same as that of another dice, these dices can be considered as identical.
Co... | [
"roll_dict = dict(E=(3, 1, 0, 5, 4, 2), W=(2, 1, 5, 0, 4, 3), S=(4, 0, 2, 3, 5, 1), N=(1, 5, 2, 3, 0, 4))\ndice1 = list(map(int, input().split()))\ndice2 = list(map(int, input().split()))\ndices = []\ndices.append(dice1)\njudge = False\nfor i in 'EWSN':\n\tdice = dices[0]\n\tnew_dice = []\n\tfor j in range(6):\n\t\... | {"inputs": ["1 2 3 2 5 6\n6 5 4 3 2 1", "1 2 3 2 5 6\n6 1 4 3 2 1", "1 2 3 2 5 6\n6 0 4 3 2 1", "1 2 3 2 5 6\n6 0 4 3 4 1", "1 2 3 2 7 6\n6 0 4 3 4 1", "1 2 3 2 7 3\n6 0 4 3 4 1", "1 2 2 2 7 6\n6 0 4 3 4 1", "1 2 2 2 7 9\n6 0 4 3 4 1", "1 2 2 2 7 9\n6 0 4 5 4 1", "1 0 2 2 7 9\n6 0 4 5 4 1", "2 0 2 2 7 9\n6 0 4 5 4 1", ... | UNKNOWN_DIFFICULTY | [] | null | aizu | [] | [] | null | 1.0 seconds | null | null | 134.217728 megabytes | null | 25,376 | 0 | roll_dict = dict(E=(3, 1, 0, 5, 4, 2), W=(2, 1, 5, 0, 4, 3), S=(4, 0, 2, 3, 5, 1), N=(1, 5, 2, 3, 0, 4))
dice1 = list(map(int, input().split()))
dice2 = list(map(int, input().split()))
dices = []
dices.append(dice1)
judge = False
for i in 'EWSN':
dice = dices[0]
new_dice = []
for j in range(6):
new_dice.append(dic... | # Question
Write a program which reads the two dices constructed in the same way as Dice I, and determines whether these two dices are identical. You can roll a dice in the same way as Dice I, and if all integers observed from the six directions are the same as that of another dice, these dices can be considered as id... | |
*Words that contain many consecutive consonants, like "schtschurowskia", are generally considered somewhat hard to pronounce.*
We say that a word is *hard to pronounce* if it contains 4 or more consonants in a row; otherwise it is *easy to pronounce*. For example, "apple" and "polish" are easy to pronounce, but "schts... | [
"for _ in range(int(input())):\n\tn = int(input())\n\ts = input()\n\tif n <= 3:\n\t\tprint('YES')\n\telse:\n\t\tfor i in range(n - 3):\n\t\t\tstring = s[i:i + 4]\n\t\t\tvow1 = 'a' in string or 'e' in string or 'i' in string\n\t\t\tvow2 = 'o' in string or 'u' in string\n\t\t\tif not vow1 and (not vow2):\n\t\t\t\tpri... | {"inputs": ["5\n5\napple\n15\nschtschurowskia\n6\npolish\n5\ntryst\n3\ncry"], "outputs": ["YES\nNO\nYES\nNO\nYES\n"]} | EASY | ['Data Structures', 'Basic Programming Concepts', 'Loops', 'String'] | null | codechef | ['String algorithms', 'Data structures'] | ['Data structures'] | https://www.codechef.com/problems/EZSPEAK | 1 seconds | 2022-07-15 | 0 | 50000 bytes | null | 25,411 | 0 | for _ in range(int(input())):
n = int(input())
s = input()
if n <= 3:
print('YES')
else:
for i in range(n - 3):
string = s[i:i + 4]
vow1 = 'a' in string or 'e' in string or 'i' in string
vow2 = 'o' in string or 'u' in string
if not vow1 and (not vow2):
print('NO')
break
else:
print('YES... | # Question
*Words that contain many consecutive consonants, like "schtschurowskia", are generally considered somewhat hard to pronounce.*
We say that a word is *hard to pronounce* if it contains 4 or more consonants in a row; otherwise it is *easy to pronounce*. For example, "apple" and "polish" are easy to pronounce... | |
You should write a simple function that takes string as input and checks if it is a valid Russian postal code, returning `true` or `false`.
A valid postcode should be 6 digits with no white spaces, letters or other symbols. Empty string should also return false.
Please also keep in mind that a valid post code **cann... | [
"def zipvalidate(postcode):\n\treturn len(postcode) == 6 and postcode.isdigit() and (postcode[0] not in '05789')\n",
"import re\n\ndef zipvalidate(postcode):\n\treturn bool(re.fullmatch('[12346]\\\\d{5}', postcode))\n",
"def zipvalidate(p):\n\treturn p.isdigit() and 100000 < int(p) < 699999 and (p[0] != '5')\n"... | def zipvalidate(postcode):
| {"fn_name": "zipvalidate", "inputs": [["142784"], ["642784"], ["111"], ["1111111"], ["AA5590"], [""], ["\n245980"], ["245980\n"], ["245980a"], ["24598a"], [" 310587 "], ["555555"], ["775255"], ["875555"], ["012345"], ["968345"], ["@68345"]], "outputs": [[true], [true], [false], [false], [false], [false], [false], [fals... | EASY | ['Regular Expressions', 'Fundamentals'] | null | codewars | ['Fundamentals'] | [] | https://www.codewars.com/kata/552e45cc30b0dbd01100001a | null | null | null | null | null | 25,421 | 0 | def zipvalidate(postcode):
return len(postcode) == 6 and postcode.isdigit() and (postcode[0] not in '05789')
| # Question
You should write a simple function that takes string as input and checks if it is a valid Russian postal code, returning `true` or `false`.
A valid postcode should be 6 digits with no white spaces, letters or other symbols. Empty string should also return false.
Please also keep in mind that a valid post... |
Given a matrix Grid[][] of size NxN. Calculate the absolute difference between the sums of its diagonals.
Example 1:
Input:
N=3
Grid=[[1,2,3],[4,5,6],[7,8,9]]
Output:
0
Explanation:
Sum of primary diagonal = 1+5+9 = 15.
Sum of secondary diagonal = 3+5+7 = 15.
Difference = |15 - 15| = 0.
Example 2:
Input:
N=3
Grid=[[1,... | [
"class Solution:\n\n\tdef diagonalSumDifference(self, N, Grid):\n\t\t(Grid1, Grid2) = (0, 0)\n\t\tfor i in range(N):\n\t\t\tfor j in range(N):\n\t\t\t\tif i == j:\n\t\t\t\t\tGrid1 += Grid[i][j]\n\t\t\t\tif i + j == N - 1:\n\t\t\t\t\tGrid2 += Grid[i][j]\n\t\treturn abs(Grid1 - Grid2)\n",
"class Solution:\n\n\tdef ... | #User function Template for python3
class Solution:
def diagonalSumDifference(self,N,Grid):
#code here | {"inputs": ["N=3\nGrid=[[1,2,3],[4,5,6],[7,8,9]]", "N=3\nGrid=[[1,1,1],[1,1,1],[1,1,1]]"], "outputs": ["0", "0"]} | EASY | ['Data Structures', 'Matrix'] | null | geeksforgeeks | ['Matrices', 'Data structures'] | ['Data structures'] | https://practice.geeksforgeeks.org/problems/find-difference-between-sum-of-diagonals1554/1 | null | null | 0 | null | O(N) | 25,419 | 0 | class Solution:
def diagonalSumDifference(self, N, Grid):
(Grid1, Grid2) = (0, 0)
for i in range(N):
for j in range(N):
if i == j:
Grid1 += Grid[i][j]
if i + j == N - 1:
Grid2 += Grid[i][j]
return abs(Grid1 - Grid2)
| # Question
Given a matrix Grid[][] of size NxN. Calculate the absolute difference between the sums of its diagonals.
Example 1:
Input:
N=3
Grid=[[1,2,3],[4,5,6],[7,8,9]]
Output:
0
Explanation:
Sum of primary diagonal = 1+5+9 = 15.
Sum of secondary diagonal = 3+5+7 = 15.
Difference = |15 - 15| = 0.
Example 2:
Input:
N... |
Dima and Seryozha live in an ordinary dormitory room for two. One day Dima had a date with his girl and he asked Seryozha to leave the room. As a compensation, Seryozha made Dima do his homework.
The teacher gave Seryozha the coordinates of n distinct points on the abscissa axis and asked to consecutively connect them... | [
"length = int(input())\nsequence = list(map(int, input().split()))\nif length <= 3:\n\tprint('no')\nelse:\n\tfor i in range(length - 1):\n\t\t(w, x) = sorted([sequence[i], sequence[i + 1]])\n\t\tfor j in range(length - 1):\n\t\t\t(y, z) = sorted([sequence[j], sequence[j + 1]])\n\t\t\tif w < y < x < z or y < w < z <... | {"inputs": ["4\n0 10 5 15\n", "4\n0 15 5 10\n", "5\n0 1000 2000 3000 1500\n", "5\n-724093 710736 -383722 -359011 439613\n", "50\n384672 661179 -775591 -989608 611120 442691 601796 502406 384323 -315945 -934146 873993 -156910 -94123 -930137 208544 816236 466922 473696 463604 794454 -872433 -149791 -858684 -467655 -55523... | MEDIUM | ['brute force', 'implementation'] | null | codeforces | ['Implementation', 'Complete search'] | ['Complete search'] | https://codeforces.com/problemset/problem/358/A | null | 2019-12-31 | null | null | null | 25,413 | 0 | length = int(input())
sequence = list(map(int, input().split()))
if length <= 3:
print('no')
else:
for i in range(length - 1):
(w, x) = sorted([sequence[i], sequence[i + 1]])
for j in range(length - 1):
(y, z) = sorted([sequence[j], sequence[j + 1]])
if w < y < x < z or y < w < z < x:
print('yes')
e... | # Question
Dima and Seryozha live in an ordinary dormitory room for two. One day Dima had a date with his girl and he asked Seryozha to leave the room. As a compensation, Seryozha made Dima do his homework.
The teacher gave Seryozha the coordinates of n distinct points on the abscissa axis and asked to consecutively ... | |
Welcome to Innopolis city. Throughout the whole year, Innopolis citizens suffer from everlasting city construction.
From the window in your room, you see the sequence of n hills, where i-th of them has height a_{i}. The Innopolis administration wants to build some houses on the hills. However, for the sake of city ap... | [
"from sys import stdin\nfrom math import ceil\nn = int(stdin.readline().strip())\ns = tuple([0] + list(map(int, stdin.readline().strip().split())) + [0])\nlim = ceil(n / 2) + 1\ndp = [[2000000002 for i in range(n + 1)] for j in range(lim)]\nvis = [[False for i in range(n + 1)] for j in range(lim)]\nfor i in range(n... | {"inputs": ["5\n1 1 1 1 1\n", "3\n1 2 3\n", "5\n1 2 3 2 2\n", "1\n10\n", "2\n1 100\n", "2\n2 2\n", "10\n2 2 4 4 3 1 1 2 3 2\n", "10\n32 48 20 20 15 2 11 5 10 34\n", "10\n99 62 10 47 53 9 83 33 15 24\n", "10\n1 2 3 4 5 6 7 8 9 10\n", "10\n5 1 6 2 8 3 4 10 9 7\n", "9\n1 100 1 100 1 100 1 100 1\n", "10\n8 9 7 6 3 2 3 2 2 ... | HARD | ['dp'] | null | codeforces | ['Dynamic programming'] | ['Dynamic programming'] | https://codeforces.com/problemset/problem/1012/C | null | 2019-12-31 | null | null | null | 25,423 | 0 | from sys import stdin
from math import ceil
n = int(stdin.readline().strip())
s = tuple([0] + list(map(int, stdin.readline().strip().split())) + [0])
lim = ceil(n / 2) + 1
dp = [[2000000002 for i in range(n + 1)] for j in range(lim)]
vis = [[False for i in range(n + 1)] for j in range(lim)]
for i in range(n + 1):
dp[0... | # Question
Welcome to Innopolis city. Throughout the whole year, Innopolis citizens suffer from everlasting city construction.
From the window in your room, you see the sequence of n hills, where i-th of them has height a_{i}. The Innopolis administration wants to build some houses on the hills. However, for the sak... | |
Given two numbers A and B. Your task is to return the sum of A and B.
Example 1:
Input:
A = 1, B = 2
Output:
3
Explanation:
Addition of 1 and 2 is 3.
Example 2:
Input:
A = 10, B = 20
Output:
30
Explanation:
Addition os 10 and 20 is 30.
Your Task:
You don't need to read input or print anything. Your task is to com... | [
"class Solution:\n\n\tdef addition(ob, A, B):\n\t\treturn A + B\n",
"class Solution:\n\n\tdef addition(ob, A, B):\n\t\tres = lambda x, y: x + y\n\t\treturn res(A, B)\n",
"class Solution:\n\n\tdef addition(ob, A, B):\n\t\tc = int(A) + int(B)\n\t\treturn c\n",
"class Solution:\n\n\tdef addition(ob, A, B):\n\t\t... | #User function Template for python3
class Solution:
def addition (ob,A,B):
# code here | {"inputs": ["A = 1, B = 2", "A = 10, B = 20"], "outputs": ["3", "30"]} | EASY | ['Algorithms', 'CPP', 'Mathematical'] | null | geeksforgeeks | ['Mathematics'] | [] | https://practice.geeksforgeeks.org/problems/addition-of-two-numbers0812/1 | null | null | 0 | null | O(1) | 25,424 | 0 | class Solution:
def addition(ob, A, B):
return A + B
| # Question
Given two numbers A and B. Your task is to return the sum of A and B.
Example 1:
Input:
A = 1, B = 2
Output:
3
Explanation:
Addition of 1 and 2 is 3.
Example 2:
Input:
A = 10, B = 20
Output:
30
Explanation:
Addition os 10 and 20 is 30.
Your Task:
You don't need to read input or print anything. Your ta... |
Given an array A of positive integers. Your task is to find the leaders in the array. An element of array is leader if it is greater than or equal to all the elements to its right side. The rightmost element is always a leader.
Example 1:
Input:
n = 6
A[] = {16,17,4,3,5,2}
Output: 17 5 2
Explanation: The first leade... | [
"class Solution:\n\n\tdef leaders(self, A, N):\n\t\tleaders = []\n\t\tmax_right = A[N - 1]\n\t\tleaders.append(max_right)\n\t\tfor i in range(N - 2, -1, -1):\n\t\t\tif A[i] >= max_right:\n\t\t\t\tleaders.append(A[i])\n\t\t\t\tmax_right = A[i]\n\t\tleaders.reverse()\n\t\treturn leaders\n",
"class Solution:\n\n\tde... | class Solution:
#Back-end complete function Template for Python 3
#Function to find the leaders in the array.
def leaders(self, A, N):
#Code here | {"inputs": ["n = 6\r\nA[] = {16,17,4,3,5,2}", "n = 5\r\nA[] = {1,2,3,4,0}"], "outputs": ["17 5 2", "4 0"]} | EASY | ['Data Structures', 'Arrays'] | null | geeksforgeeks | ['Data structures'] | ['Data structures'] | https://practice.geeksforgeeks.org/problems/leaders-in-an-array-1587115620/1 | null | null | 0 | null | O(n) | 25,420 | 0 | class Solution:
def leaders(self, A, N):
leaders = []
max_right = A[N - 1]
leaders.append(max_right)
for i in range(N - 2, -1, -1):
if A[i] >= max_right:
leaders.append(A[i])
max_right = A[i]
leaders.reverse()
return leaders
| # Question
Given an array A of positive integers. Your task is to find the leaders in the array. An element of array is leader if it is greater than or equal to all the elements to its right side. The rightmost element is always a leader.
Example 1:
Input:
n = 6
A[] = {16,17,4,3,5,2}
Output: 17 5 2
Explanation: The... |
Given a non-empty array of unique positive integers A, consider the following graph:
There are A.length nodes, labelled A[0] to A[A.length - 1];
There is an edge between A[i] and A[j] if and only if A[i] and A[j] share a common factor greater than 1.
Return the size of the largest connected component in the graph.
... | [
"from collections import defaultdict\n\nclass Solution:\n\tMAXPRIME = 100001\n\tisPrime = [0 for _ in range(MAXPRIME + 1)]\n\tisPrime[0] = -1\n\tisPrime[1] = -1\n\tfor i in range(2, MAXPRIME):\n\t\tif isPrime[i] == 0:\n\t\t\tfor multiple in range(i * i, MAXPRIME + 1, i):\n\t\t\t\tif isPrime[multiple] == 0:\n\t\t\t\... | class Solution:
def largestComponentSize(self, A: List[int]) -> int:
| {"fn_name": "largestComponentSize", "inputs": [[[4, 6, 15, 35]]], "outputs": [4]} | MEDIUM | ['Union Find', 'Math', 'Array'] | null | leetcode | ['Spanning trees', 'Data structures', 'Mathematics'] | ['Data structures'] | https://leetcode.com/problems/largest-component-size-by-common-factor/ | null | null | null | null | null | 25,394 | 0 | from collections import defaultdict
class Solution:
MAXPRIME = 100001
isPrime = [0 for _ in range(MAXPRIME + 1)]
isPrime[0] = -1
isPrime[1] = -1
for i in range(2, MAXPRIME):
if isPrime[i] == 0:
for multiple in range(i * i, MAXPRIME + 1, i):
if isPrime[multiple] == 0:
isPrime[multiple] = i
isPrime... | # Question
Given a non-empty array of unique positive integers A, consider the following graph:
There are A.length nodes, labelled A[0] to A[A.length - 1];
There is an edge between A[i] and A[j] if and only if A[i] and A[j] share a common factor greater than 1.
Return the size of the largest connected component in t... |
Given a Binary Search Tree (BST) and a range [min, max], remove all keys which are outside the given range. The modified tree should also be BST.
Example 1:
Input:
Range = [-10, 13]
Output:
-8 6 7 13
Explanation:
Nodes with values -13, 14 and 15 are
outside the given range and hence are
removed from the BST.
This is ... | [
"class Solution:\n\n\tdef removekeys(self, root, l, r):\n\t\tif root is None:\n\t\t\treturn root\n\t\troot.left = self.removekeys(root.left, l, r)\n\t\troot.right = self.removekeys(root.right, l, r)\n\t\tif root.data > r:\n\t\t\treturn root.left\n\t\tif root.data < l:\n\t\t\treturn root.right\n\t\treturn root\n",
... | #User function Template for python3
'''
class Node:
def __init__(self, val):
self.right = None
self.data = val
self.left = None
'''
class Solution:
def removekeys(self, root, l, r):
#code here | {"inputs": ["Range = [-10, 13]", "Range = [2, 6]\r\n 14\r\n / \\\r\n 4 16\r\n / \\ /\r\n 2 8 15\r\n / \\ / \\\r\n -8 3 7 10"], "outputs": ["-8 6 7 13", "2 3 4"]} | MEDIUM | ['Data Structures', 'Binary Search Tree'] | null | geeksforgeeks | ['Data structures', 'Range queries'] | ['Data structures', 'Range queries'] | https://practice.geeksforgeeks.org/problems/remove-bst-keys-outside-given-range/1 | null | null | 2 | null | O(number of nodes) | 25,426 | 0 | class Solution:
def removekeys(self, root, l, r):
if root is None:
return root
root.left = self.removekeys(root.left, l, r)
root.right = self.removekeys(root.right, l, r)
if root.data > r:
return root.left
if root.data < l:
return root.right
return root
| # Question
Given a Binary Search Tree (BST) and a range [min, max], remove all keys which are outside the given range. The modified tree should also be BST.
Example 1:
Input:
Range = [-10, 13]
Output:
-8 6 7 13
Explanation:
Nodes with values -13, 14 and 15 are
outside the given range and hence are
removed from the B... |
You are given two string S and T. Find the maximal length of some prefix of the string S which occurs in strings T as subsequence.
Input
The first line contains string S.
The second line contains string T.
Both strings consist of lowecase Latin letters.
Output
Output one integer - answer to the question.
Constraints... | [
"\nfrom collections import deque, defaultdict, Counter\nfrom math import factorial\nfrom fractions import gcd\nfrom sys import stdin, exit\nfrom itertools import *\nimport heapq\nimport string\nimport re\n\n\ndef prase(T):\n\tif T == 1:\n\t\treturn list(map(int, testcase.next().strip().split()))\n\treturn testcase.... | {"inputs": ["informatika\ninformatikainformatikainformatika\n", "qwertyuiopasdfghjklzxcvbnm\nmnbvcxzlkjhgfdsapoiuytrewq\n", "digger\nbiggerdiagram\n", "aaaaa\nkxqsrpzkxhzxvrglprtjjmukrzitcliouwjfjijwnuiwxqfiogfkxokxehdrihkoynezjddjkxwogyncwzhvhxqinmcdgrphmtxmogymewccrwtgucvicojcwvnxdcesjqdnddnsdutkxaaqrrtvifwjhxmwptscl... | EASY | ['StringAlgorithms', 'Ad-Hoc'] | prefpref | hackerearth | ['String algorithms', 'Ad-hoc'] | [] | null | null | null | null | null | null | 25,429 | 0 |
from collections import deque, defaultdict, Counter
from math import factorial
from fractions import gcd
from sys import stdin, exit
from itertools import *
import heapq
import string
import re
def prase(T):
if T == 1:
return list(map(int, testcase.next().strip().split()))
return testcase.next().strip().split()
... | # Question
You are given two string S and T. Find the maximal length of some prefix of the string S which occurs in strings T as subsequence.
Input
The first line contains string S.
The second line contains string T.
Both strings consist of lowecase Latin letters.
Output
Output one integer - answer to the question.
... | |
Lia is fascinated by anything she considers to be a twin. She calls a pairs of positive integers, $\boldsymbol{i}$ and $j$, twins if:
They are both prime. A prime number is an integer greater than $\mbox{1}$ that has no positive divisors other than $\mbox{1}$ and itself.
Their absolute difference is exactly equal to ... | [
"limit = 1000000\n(beg, end) = map(int, input().strip().split(' '))\nis_prime = [False] * (limit + 1)\nprime = []\nfor x in range(1, int(limit ** 0.5) + 1):\n\tfor y in range(1, int(limit ** 0.5) + 1):\n\t\tn = 4 * x ** 2 + y ** 2\n\t\tif n <= limit and (n % 12 == 1 or n % 12 == 5):\n\t\t\tis_prime[n] = not is_prim... | {"inputs": ["3 13\n"], "outputs": ["3\n"]} | MEDIUM | ['Mathematics - Number Theory'] | null | hackerrank | ['Number theory'] | [] | https://www.hackerrank.com/challenges/twins/problem | null | null | 0 | null | null | 25,425 | 0 | limit = 1000000
(beg, end) = map(int, input().strip().split(' '))
is_prime = [False] * (limit + 1)
prime = []
for x in range(1, int(limit ** 0.5) + 1):
for y in range(1, int(limit ** 0.5) + 1):
n = 4 * x ** 2 + y ** 2
if n <= limit and (n % 12 == 1 or n % 12 == 5):
is_prime[n] = not is_prime[n]
n = 3 * x ** 2... | # Question
Lia is fascinated by anything she considers to be a twin. She calls a pairs of positive integers, $\boldsymbol{i}$ and $j$, twins if:
They are both prime. A prime number is an integer greater than $\mbox{1}$ that has no positive divisors other than $\mbox{1}$ and itself.
Their absolute difference is exact... | |
Pak Chanek, a renowned scholar, invented a card puzzle using his knowledge. In the puzzle, you are given a board with $n$ rows and $m$ columns. Let $(r, c)$ represent the cell in the $r$-th row and the $c$-th column.
Initially, there are $k$ cards stacked in cell $(1, 1)$. Each card has an integer from $1$ to $k$ writ... | [
"import sys\ninput = sys.stdin.readline\n\ndef readList():\n\treturn list(map(int, input().split()))\n\ndef readInt():\n\treturn int(input())\n\ndef readInts():\n\treturn map(int, input().split())\n\ndef readStr():\n\treturn input().strip()\n\ndef solve():\n\t(n, m, k) = readInts()\n\tarr = readList()\n\tisPresent ... | {"inputs": ["4\n3 3 6\n3 6 4 1 2 5\n3 3 10\n1 2 3 4 5 6 7 8 9 10\n5 4 4\n2 1 3 4\n3 4 10\n10 4 9 3 5 6 8 2 7 1\n"], "outputs": ["YA\nTIDAK\nYA\nYA\n"]} | MEDIUM | ['data structures', 'constructive algorithms'] | null | codeforces | ['Data structures', 'Constructive algorithms'] | ['Data structures'] | https://codeforces.com/problemset/problem/1740/D | 1 second | 2022-10-29 | 1 | 256 megabytes | null | 25,428 | 0 | import sys
input = sys.stdin.readline
def readList():
return list(map(int, input().split()))
def readInt():
return int(input())
def readInts():
return map(int, input().split())
def readStr():
return input().strip()
def solve():
(n, m, k) = readInts()
arr = readList()
isPresent = [False] * (k + 1)
curr = k
... | # Question
Pak Chanek, a renowned scholar, invented a card puzzle using his knowledge. In the puzzle, you are given a board with $n$ rows and $m$ columns. Let $(r, c)$ represent the cell in the $r$-th row and the $c$-th column.
Initially, there are $k$ cards stacked in cell $(1, 1)$. Each card has an integer from $1$... | |
We call a string good, if after merging all the consecutive equal characters, the resulting string is palindrome. For example, "aabba" is good, because after the merging step it will become "aba".
Given a string, you have to find two values: the number of good substrings of even length; the number of good substrings... | [
"def R():\n\treturn map(int, input().split())\n\ndef I():\n\treturn int(input())\n\ndef S():\n\treturn str(input())\n\ndef L():\n\treturn list(R())\nfrom collections import Counter\nimport math\nimport sys\nfrom itertools import permutations\nimport bisect\nmod = 10 ** 9 + 7\ns = S()\nl = len(s)\nA = [0] * 2\nB = [... | {"inputs": ["bb\n", "baab\n", "babb\n", "babaa\n", "baabbbb\n", "babbbbbaaabaabbabbabbababbaaba\n", "baabaababaabbaabaaabbbaaaaaabbbabaaaabbbaaaaaaaaabbaabbbaabbaabbaabbababbbbbaaabbaabaaaaabaababbbbababaabaababbbaabbbaabbbbaaaabaabbbaabbbbbabbbabbabaaaabbbabbbaabaaaabbbbabbbababbabaaaabbabababbaaaaaabaabaaaaabbbbabbab... | HARD | ['math'] | null | codeforces | ['Mathematics'] | [] | https://codeforces.com/problemset/problem/451/D | null | 2019-12-31 | null | null | null | 25,430 | 0 | def R():
return map(int, input().split())
def I():
return int(input())
def S():
return str(input())
def L():
return list(R())
from collections import Counter
import math
import sys
from itertools import permutations
import bisect
mod = 10 ** 9 + 7
s = S()
l = len(s)
A = [0] * 2
B = [0] * 2
for i in range(2):
A[... | # Question
We call a string good, if after merging all the consecutive equal characters, the resulting string is palindrome. For example, "aabba" is good, because after the merging step it will become "aba".
Given a string, you have to find two values: the number of good substrings of even length; the number of goo... | |
# Introduction and Warm-up (Highly recommended)
# [Playing With Lists/Arrays Series](https://www.codewars.com/collections/playing-with-lists-slash-arrays)
___
# Task
**_Given_** an *array/list [] of integers* , **_Find_** *the Nth smallest element in this array of integers*
___
# Notes
* **_Array/list_** size is... | [
"def nth_smallest(arr, pos):\n\treturn sorted(arr)[pos - 1]\n",
"from heapq import nsmallest\n\ndef nth_smallest(arr, pos):\n\treturn nsmallest(pos, arr)[-1]\n",
"def nth_smallest(arr, pos):\n\tarr.sort()\n\treturn arr[pos - 1]\n",
"import random\n\ndef quick_select(arr, pos):\n\tpivot = random.choice(arr)\n\... | def nth_smallest(arr, pos):
| {"fn_name": "nth_smallest", "inputs": [[[3, 1, 2], 2], [[15, 20, 7, 10, 4, 3], 3], [[-5, -1, -6, -18], 4], [[-102, -16, -1, -2, -367, -9], 5], [[2, 169, 13, -5, 0, -1], 4]], "outputs": [[2], [7], [-1], [-2], [2]]} | EASY | ['Arrays', 'Fundamentals'] | null | codewars | ['Fundamentals', 'Data structures'] | ['Data structures'] | https://www.codewars.com/kata/5a512f6a80eba857280000fc | null | null | null | null | null | 25,427 | 0 | def nth_smallest(arr, pos):
return sorted(arr)[pos - 1]
| # Question
# Introduction and Warm-up (Highly recommended)
# [Playing With Lists/Arrays Series](https://www.codewars.com/collections/playing-with-lists-slash-arrays)
___
# Task
**_Given_** an *array/list [] of integers* , **_Find_** *the Nth smallest element in this array of integers*
___
# Notes
* **_Array/lis... |
One day, Delta, the dog, got very angry. He has $N$ items with different values, and he decided to destroy a few of them. However, Delta loves his hooman as well. So he only destroyed those items whose Least Significant Bit in binary representation is 0.
Can you help Delta to find the total damage he did so he could m... | [
"for test in range(int(input())):\n\tn = int(input())\n\tar = list(map(int, input().split()))\n\tcount = 0\n\tfor item in ar:\n\t\tif bin(item)[-1] == '0':\n\t\t\tcount += item\n\tprint(count)\n",
"def bit(x):\n\ts = 0\n\tfor i in range(len(x)):\n\t\tp = bool(x[i] & 1 << 0)\n\t\tif p == False:\n\t\t\ts = s + x[i]... | {"inputs": [["1", "5", "1 2 3 4 5"]], "outputs": [["6"]]} | UNKNOWN_DIFFICULTY | [] | null | codechef | [] | [] | https://www.codechef.com/ENAU2020/problems/ECAUG202 | null | null | null | null | null | 25,433 | 0 | for test in range(int(input())):
n = int(input())
ar = list(map(int, input().split()))
count = 0
for item in ar:
if bin(item)[-1] == '0':
count += item
print(count)
| # Question
One day, Delta, the dog, got very angry. He has $N$ items with different values, and he decided to destroy a few of them. However, Delta loves his hooman as well. So he only destroyed those items whose Least Significant Bit in binary representation is 0.
Can you help Delta to find the total damage he did s... | |
Chef's college is starting next week. There are $S$ subjects in total, and he needs to choose $K$ of them to attend each day, to fulfill the required number of credits to pass the semester. There are $N + 1$ buildings. His hostel is in building number $0$. Subject $i$ is taught in building $A_{i}$. After each subject, ... | [
"from collections import deque\n\ndef BFS(bldg, s):\n\tqueue = deque()\n\tqueue.append(s)\n\tcost = [-1 for i in range(n + 1)]\n\tcost[s] = 0\n\twhile queue:\n\t\ts = queue.popleft()\n\t\tfor i in bldg[s]:\n\t\t\tif cost[i] == -1:\n\t\t\t\tqueue.append(i)\n\t\t\t\tcost[i] = cost[s] + 1\n\treturn cost\nfor _ in rang... | {"inputs": ["3\n2 3 2 2\n0 1\n1 2\n2 0\n1 2\n2 2 2 2\n0 1\n1 2\n1 2\n6 7 5 3\n0 1\n0 2\n0 4\n1 3\n1 4\n2 5\n2 6\n1 2 3 5 6"], "outputs": ["4\n6\n8"]} | VERY_HARD | ['Algorithms', 'Shortest Paths', 'BFS', 'Traversals', 'Graphs', "Dijkstra's Algorithm", 'Graph Algos', 'Data Structures'] | null | codechef | ['Data structures', 'Graph algorithms', 'Graph traversal', 'Shortest paths'] | ['Data structures'] | https://www.codechef.com/problems/CLASSES | 1 seconds | 2020-12-30 | 0 | 50000 bytes | null | 25,434 | 0 | from collections import deque
def BFS(bldg, s):
queue = deque()
queue.append(s)
cost = [-1 for i in range(n + 1)]
cost[s] = 0
while queue:
s = queue.popleft()
for i in bldg[s]:
if cost[i] == -1:
queue.append(i)
cost[i] = cost[s] + 1
return cost
for _ in range(int(input())):
(n, m, s, k) = map(int... | # Question
Chef's college is starting next week. There are $S$ subjects in total, and he needs to choose $K$ of them to attend each day, to fulfill the required number of credits to pass the semester. There are $N + 1$ buildings. His hostel is in building number $0$. Subject $i$ is taught in building $A_{i}$. After ea... | |
Given an array arr[ ] of size n such that elements of arr[ ] in range [0, 1, ..n-1]. Our task is to divide the array into the maximum number of partitions that can be sorted individually, then concatenated to make the whole array sorted.
Example 1:
ââ¬â¹Input : arr[ ] = {2, 1, 0, 3}
Output : 2
Explanation:
If divid... | [
"def maxPartitions(arr, n):\n\ta = arr[0]\n\tc = 0\n\tfor i in range(n):\n\t\tif a < arr[i]:\n\t\t\ta = arr[i]\n\t\tif a == i:\n\t\t\tc += 1\n\treturn c\n",
"def maxPartitions(arr, n):\n\tmaxi = 0\n\tcount = 0\n\tfor (i, item) in enumerate(arr):\n\t\tmaxi = max(maxi, item)\n\t\tcount += maxi == i\n\treturn count\... | #User function Template for python3
def maxPartitions (arr, n) :
#Complete the function
| {"fn_name": "maxPartitions", "inputs": ["arr[ ] = {2, 1, 0, 3}", "arr[ ] = {2, 1, 0, 3, 4, 5}"], "outputs": ["2", "4"]} | EASY | ['Data Structures', 'Arrays', 'Algorithms', 'Sorting'] | null | geeksforgeeks | ['Sorting', 'Data structures'] | ['Sorting', 'Data structures'] | https://practice.geeksforgeeks.org/problems/maximum-number-of-partitions-that-can-be-sorted-individually-to-make-sorted2926/1 | null | null | 0 | null | O(N). | 25,435 | 0 | def maxPartitions(arr, n):
a = arr[0]
c = 0
for i in range(n):
if a < arr[i]:
a = arr[i]
if a == i:
c += 1
return c
| # Question
Given an array arr[ ] of size n such that elements of arr[ ] in range [0, 1, ..n-1]. Our task is to divide the array into the maximum number of partitions that can be sorted individually, then concatenated to make the whole array sorted.
Example 1:
ââ¬â¹Input : arr[ ] = {2, 1, 0, 3}
Output : 2
Explanati... |
Mad scientist Mike is busy carrying out experiments in chemistry. Today he will attempt to join three atoms into one molecule.
A molecule consists of atoms, with some pairs of atoms connected by atomic bonds. Each atom has a valence number — the number of bonds the atom must form with other atoms. An atom can form one... | [
"a = list(map(int, input().split()))\nif sum(a) % 2 == 1 or max(a) > sum(a) - max(a):\n\tprint('Impossible')\nelif len(set(a)) == 1:\n\tprint(a[0] // 2, a[0] // 2, a[0] // 2)\nelif a.count(min(a)) == 2:\n\tpos = a.index(max(a))\n\tans = [0] * 3\n\tans[pos] = ans[pos - 1] = max(a) // 2\n\tans[pos - 2] = (min(a) * 2 ... | {"inputs": ["1 1 2\n", "3 4 5\n", "4 1 1\n", "1 1 1\n", "1000000 1000000 1000000\n", "3 11 8\n", "8 5 12\n", "1000000 500000 1\n", "1000000 500000 2\n", "2 2 2\n", "3 3 3\n", "4 4 4\n", "2 4 2\n", "10 5 14\n", "10 5 15\n", "10 4 16\n", "3 3 6\n", "9 95 90\n", "3 5 8\n", "5 8 13\n", "6 1 5\n", "59 54 56\n", "246 137 940... | EASY | ['brute force', 'graphs', 'math'] | null | codeforces | ['Graph algorithms', 'Mathematics', 'Complete search'] | ['Complete search'] | https://codeforces.com/problemset/problem/344/B | null | 2019-12-31 | null | null | null | 25,432 | 0 | a = list(map(int, input().split()))
if sum(a) % 2 == 1 or max(a) > sum(a) - max(a):
print('Impossible')
elif len(set(a)) == 1:
print(a[0] // 2, a[0] // 2, a[0] // 2)
elif a.count(min(a)) == 2:
pos = a.index(max(a))
ans = [0] * 3
ans[pos] = ans[pos - 1] = max(a) // 2
ans[pos - 2] = (min(a) * 2 - max(a)) // 2
prin... | # Question
Mad scientist Mike is busy carrying out experiments in chemistry. Today he will attempt to join three atoms into one molecule.
A molecule consists of atoms, with some pairs of atoms connected by atomic bonds. Each atom has a valence number — the number of bonds the atom must form with other atoms. An atom ... | |
A remote island chain contains n islands, labeled 1 through n. Bidirectional bridges connect the islands to form a simple cycle — a bridge connects islands 1 and 2, islands 2 and 3, and so on, and additionally a bridge connects islands n and 1. The center of each island contains an identical pedestal, and all but one o... | [
"input()\nl1 = [int(x) for x in input().split() if x != '0']\nl2 = [int(x) for x in input().split() if x != '0']\nm = len(l1)\nx = l1.index(l2[0])\nb = True\nfor i in range(len(l1)):\n\tb &= l2[i] == l1[(x + i) % m]\nprint('YES' if b else 'NO')\n",
"n = int(input())\na = list(map(int, input().split()))\nb = list(... | {"inputs": ["3\n1 0 2\n2 0 1\n", "2\n1 0\n0 1\n", "4\n1 2 3 0\n0 3 2 1\n", "9\n3 8 4 6 7 1 5 2 0\n6 4 8 5 3 1 2 0 7\n", "4\n2 3 1 0\n2 0 1 3\n", "4\n0 1 2 3\n2 0 1 3\n", "4\n3 0 1 2\n1 0 2 3\n", "3\n0 2 1\n1 2 0\n", "2\n0 1\n0 1\n", "6\n3 1 5 4 0 2\n0 4 3 5 2 1\n", "4\n2 0 3 1\n3 1 0 2\n", "5\n3 0 2 1 4\n4 3 0 1 2\n", ... | EASY | ['implementation', 'constructive algorithms'] | null | codeforces | ['Implementation', 'Constructive algorithms'] | [] | https://codeforces.com/problemset/problem/634/A | null | 2019-12-31 | null | null | null | 25,436 | 0 | input()
l1 = [int(x) for x in input().split() if x != '0']
l2 = [int(x) for x in input().split() if x != '0']
m = len(l1)
x = l1.index(l2[0])
b = True
for i in range(len(l1)):
b &= l2[i] == l1[(x + i) % m]
print('YES' if b else 'NO')
| # Question
A remote island chain contains n islands, labeled 1 through n. Bidirectional bridges connect the islands to form a simple cycle — a bridge connects islands 1 and 2, islands 2 and 3, and so on, and additionally a bridge connects islands n and 1. The center of each island contains an identical pedestal, and a... | |
#Sorting on planet Twisted-3-7
There is a planet... in a galaxy far far away. It is exactly like our planet, but it has one difference:
#The values of the digits 3 and 7 are twisted.
Our 3 means 7 on the planet Twisted-3-7. And 7 means 3.
Your task is to create a method, that can sort an array the way it would be sor... | [
"def sort_twisted37(arr):\n\n\tdef key(x):\n\t\treturn int(str(x).translate(str.maketrans('37', '73')))\n\treturn sorted(arr, key=key)\n",
"tr = str.maketrans('37', '73')\n\ndef sort_twisted37(arr):\n\treturn sorted(arr, key=lambda n: int(str(n).translate(tr)))\n",
"def sort_twisted37(arr):\n\ttwisted = lambda ... | def sort_twisted37(arr):
| {"fn_name": "sort_twisted37", "inputs": [[[1, 2, 3, 4, 5, 6, 7, 8, 9]], [[12, 13, 14]], [[9, 2, 4, 7, 3]]], "outputs": [[[1, 2, 7, 4, 5, 6, 3, 8, 9]], [[12, 14, 13]], [[2, 7, 4, 3, 9]]]} | EASY | ['Mathematics', 'Arrays', 'Algorithms', 'Sorting'] | null | codewars | ['Sorting', 'Data structures', 'Mathematics'] | ['Sorting', 'Data structures'] | https://www.codewars.com/kata/58068479c27998b11900056e | null | null | null | null | null | 25,440 | 0 | def sort_twisted37(arr):
def key(x):
return int(str(x).translate(str.maketrans('37', '73')))
return sorted(arr, key=key)
| # Question
#Sorting on planet Twisted-3-7
There is a planet... in a galaxy far far away. It is exactly like our planet, but it has one difference:
#The values of the digits 3 and 7 are twisted.
Our 3 means 7 on the planet Twisted-3-7. And 7 means 3.
Your task is to create a method, that can sort an array the way it ... |
One day Polycarpus got hold of two non-empty strings s and t, consisting of lowercase Latin letters. Polycarpus is quite good with strings, so he immediately wondered, how many different pairs of "x y" are there, such that x is a substring of string s, y is a subsequence of string t, and the content of x and y is the s... | [
"from sys import stdin\ns = [ord(i) - 97 for i in stdin.readline().strip()]\ns1 = [ord(i) - 97 for i in stdin.readline().strip()]\nn = len(s)\nm = len(s1)\nmod = 1000000007\ndp = [[0 for i in range(n)] for j in range(26)]\nfor i in range(m):\n\tarr = [0 for j in range(n)]\n\tfor j in range(n):\n\t\tif s1[i] == s[j]... | {"inputs": ["bbabb\nbababbbbab\n", "ab\nbbbba\n", "xzzxxxzxzzzxzzzxxzzxzzxzxzxxzxxzxxzxzzxxzxxzxxxzxzxzxxzzxxxxzxzzzxxxzxzxxxzzxxzxxzxxzzxxzxxzxzxzzzxzzzzxzxxzzxzxxzxxzzxzxzx\nzzx\n", "a\nb\n", "zxzxzxzxzxzxzx\nd\n", "pfdempfohomnpgbeegikfmflnalbbajpnpgeacaicoehopgnabnklheepnlnflohjegcciflmfjhachnhekckfjgoffhkblncidn\n... | MEDIUM_HARD | ['dp'] | null | codeforces | ['Dynamic programming'] | ['Dynamic programming'] | https://codeforces.com/problemset/problem/163/A | 2.0 seconds | null | null | 256.0 megabytes | null | 25,442 | 0 | from sys import stdin
s = [ord(i) - 97 for i in stdin.readline().strip()]
s1 = [ord(i) - 97 for i in stdin.readline().strip()]
n = len(s)
m = len(s1)
mod = 1000000007
dp = [[0 for i in range(n)] for j in range(26)]
for i in range(m):
arr = [0 for j in range(n)]
for j in range(n):
if s1[i] == s[j]:
arr[j] = 1
... | # Question
One day Polycarpus got hold of two non-empty strings s and t, consisting of lowercase Latin letters. Polycarpus is quite good with strings, so he immediately wondered, how many different pairs of "x y" are there, such that x is a substring of string s, y is a subsequence of string t, and the content of x an... | |
Katya studies in a fifth grade. Recently her class studied right triangles and the Pythagorean theorem. It appeared, that there are triples of positive integers such that you can construct a right triangle with segments of lengths corresponding to triple. Such triples are called Pythagorean triples.
For example, tripl... | [
"import sys, os, io\n\ndef rs():\n\treturn sys.stdin.readline().rstrip()\n\ndef ri():\n\treturn int(sys.stdin.readline())\n\ndef ria():\n\treturn list(map(int, sys.stdin.readline().split()))\n\ndef ws(s):\n\tsys.stdout.write(s + '\\n')\n\ndef wi(n):\n\tsys.stdout.write(str(n) + '\\n')\n\ndef wia(a):\n\tsys.stdout.w... | {"inputs": ["3\n", "6\n", "1\n", "17\n", "67\n", "10\n", "14\n", "22\n", "23\n", "246\n", "902\n", "1000000000\n", "1998\n", "2222222\n", "2222226\n", "1111110\n", "9999998\n", "1024\n", "8388608\n", "4\n", "8\n", "16\n", "492\n", "493824\n", "493804\n", "493800\n", "2048\n", "8388612\n", "44\n", "444\n", "4444\n", "44... | MEDIUM | ['number theory', 'math'] | null | codeforces | ['Number theory', 'Mathematics'] | [] | https://codeforces.com/problemset/problem/707/C | null | 2019-12-31 | null | null | null | 25,431 | 0 | import sys, os, io
def rs():
return sys.stdin.readline().rstrip()
def ri():
return int(sys.stdin.readline())
def ria():
return list(map(int, sys.stdin.readline().split()))
def ws(s):
sys.stdout.write(s + '\n')
def wi(n):
sys.stdout.write(str(n) + '\n')
def wia(a):
sys.stdout.write(' '.join([str(x) for x in ... | # Question
Katya studies in a fifth grade. Recently her class studied right triangles and the Pythagorean theorem. It appeared, that there are triples of positive integers such that you can construct a right triangle with segments of lengths corresponding to triple. Such triples are called Pythagorean triples.
For ex... | |
Given an integer, $n$, print the following values for each integer $\boldsymbol{i}$ from $\mbox{1}$ to $n$:
Decimal
Octal
Hexadecimal (capitalized)
Binary
Function Description
Complete the print_formatted function in the editor below.
print_formatted has the following parameters:
int number: the maximum v... | [
"N = int(input())\nwidth = len(str(bin(N))) - 2\nfor n in range(1, N + 1):\n\tfor base in 'doXb':\n\t\tprint('{0:{width}{base}}'.format(n, base=base, width=width), end=' ')\n\tprint()\n",
"N = int(input())\npaddingLength = len(bin(N)[2:])\npadding = ' ' * paddingLength\nfor i in range(1, N + 1):\n\tprint(('{0:>' ... | {"inputs": ["17\n"], "outputs": [" 1 1 1 1\n 2 2 2 10\n 3 3 3 11\n 4 4 4 100\n 5 5 5 101\n 6 6 6 110\n 7 7 7 111\n 8 10 8 1000\n 9 11 9 1001\n 10 12 A 1010\n 11 13 B 1011\n 12 14... | EASY | ['Python - Strings'] | null | hackerrank | ['String algorithms'] | [] | https://www.hackerrank.com/challenges/python-string-formatting/problem | null | null | 0 | null | null | 25,437 | 0 | N = int(input())
width = len(str(bin(N))) - 2
for n in range(1, N + 1):
for base in 'doXb':
print('{0:{width}{base}}'.format(n, base=base, width=width), end=' ')
print()
| # Question
Given an integer, $n$, print the following values for each integer $\boldsymbol{i}$ from $\mbox{1}$ to $n$:
Decimal
Octal
Hexadecimal (capitalized)
Binary
Function Description
Complete the print_formatted function in the editor below.
print_formatted has the following parameters:
int number: t... | |
You are given a permutation $p_1, p_2, \ldots, p_n$ of integers from $1$ to $n$ and an integer $k$, such that $1 \leq k \leq n$. A permutation means that every number from $1$ to $n$ is contained in $p$ exactly once.
Let's consider all partitions of this permutation into $k$ disjoint segments. Formally, a partition is... | [
"(n, k) = [int(el) for el in input().split()]\nper = [int(el) for el in input().split()]\nsp = sorted(per, reverse=True)\nsp.append(0)\nmod = 998244353\nresult = 1\nprev = 0\nfor (i, p) in enumerate(per, 1):\n\tif p > sp[k]:\n\t\tif not prev:\n\t\t\tprev = i\n\t\telse:\n\t\t\tresult *= i - prev\n\t\t\tresult %= mod... | {"inputs": ["3 2\n2 1 3\n", "5 5\n2 1 5 3 4\n", "7 3\n2 7 3 1 5 4 6\n", "1 1\n1\n", "2 1\n1 2\n", "2 2\n2 1\n", "3 2\n3 2 1\n", "5 4\n2 1 3 5 4\n", "10 3\n4 6 7 8 9 1 10 3 5 2\n", "100 77\n59 92 18 16 45 82 63 43 50 68 19 13 53 79 48 28 94 49 25 77 54 8 61 66 40 100 99 20 35 14 52 56 22 17 57 36 23 90 4 65 84 42 30 27 ... | EASY | ['greedy', 'combinatorics', 'math'] | null | codeforces | ['Combinatorics', 'Mathematics', 'Greedy algorithms'] | ['Greedy algorithms'] | https://codeforces.com/problemset/problem/1326/C | 1 second | 2020-03-19 | 0 | 256 megabytes | null | 25,409 | 0 | (n, k) = [int(el) for el in input().split()]
per = [int(el) for el in input().split()]
sp = sorted(per, reverse=True)
sp.append(0)
mod = 998244353
result = 1
prev = 0
for (i, p) in enumerate(per, 1):
if p > sp[k]:
if not prev:
prev = i
else:
result *= i - prev
result %= mod
prev = i
print(sum(sp[:k]), ... | # Question
You are given a permutation $p_1, p_2, \ldots, p_n$ of integers from $1$ to $n$ and an integer $k$, such that $1 \leq k \leq n$. A permutation means that every number from $1$ to $n$ is contained in $p$ exactly once.
Let's consider all partitions of this permutation into $k$ disjoint segments. Formally, a ... | |
Easy and hard versions are actually different problems, so read statements of both problems completely and carefully.
Summer vacation has started so Alice and Bob want to play and joy, but... Their mom doesn't think so. She says that they have to read some amount of books before all entertainments. Alice and Bob will ... | [
"(n, k) = map(int, input().split())\na = []\nb = []\nboth = []\nfor _ in range(n):\n\t(x, y, z) = map(int, input().split())\n\tif y == 1 and z == 1:\n\t\tboth.append(x)\n\telif y == 1:\n\t\ta.append(x)\n\telif z == 1:\n\t\tb.append(x)\na.sort()\nb.sort()\nfor i in range(min(len(a), len(b))):\n\tboth.append(a[i] + b... | {"inputs": ["8 4\n7 1 1\n2 1 1\n4 0 1\n8 1 1\n1 0 1\n1 1 1\n1 0 1\n3 0 0\n", "5 2\n6 0 0\n9 0 0\n1 0 1\n2 1 1\n5 1 0\n", "5 3\n3 0 0\n2 1 0\n3 1 0\n5 0 1\n3 0 1\n", "3 1\n3 0 1\n3 1 0\n3 0 0\n", "2 1\n7 1 1\n2 1 1\n", "5 1\n2 1 0\n2 0 1\n1 0 1\n1 1 0\n1 0 1\n", "6 3\n7 1 1\n8 0 0\n9 1 1\n6 1 0\n10 1 1\n5 0 0\n", "2 1\n... | MEDIUM_HARD | ['data structures', 'greedy', 'sortings'] | null | codeforces | ['Sorting', 'Data structures', 'Greedy algorithms'] | ['Sorting', 'Data structures', 'Greedy algorithms'] | https://codeforces.com/problemset/problem/1374/E1 | 2 seconds | 2020-06-28 | 0 | 256 megabytes | null | 25,387 | 0 | (n, k) = map(int, input().split())
a = []
b = []
both = []
for _ in range(n):
(x, y, z) = map(int, input().split())
if y == 1 and z == 1:
both.append(x)
elif y == 1:
a.append(x)
elif z == 1:
b.append(x)
a.sort()
b.sort()
for i in range(min(len(a), len(b))):
both.append(a[i] + b[i])
both.sort()
if len(both) <... | # Question
Easy and hard versions are actually different problems, so read statements of both problems completely and carefully.
Summer vacation has started so Alice and Bob want to play and joy, but... Their mom doesn't think so. She says that they have to read some amount of books before all entertainments. Alice a... | |
Professor GukiZ likes programming contests. He especially likes to rate his students on the contests he prepares. Now, he has decided to prepare a new contest.
In total, n students will attend, and before the start, every one of them has some positive integer rating. Students are indexed from 1 to n. Let's denote the... | [
"(n, x) = (int(input()), list(map(int, input().split(' '))))\ntmp = sorted(x, reverse=True)\nfor i in x:\n\tprint(tmp.index(i) + 1)\n",
"n = int(input())\nl = list(map(int, input().split()))\npos = 1\nm = l[:]\nm.sort()\nm = m[::-1]\nres = []\nfor i in range(n):\n\tres.append(m.index(l[i]) + 1)\nfor j in res:\n\t... | {"inputs": ["8\n153 100 87 14 10 8 6 5\n", "70\n11 54 37 62 1 46 13 17 38 47 28 15 63 5 61 34 49 66 32 59 3 41 58 28 23 62 41 64 20 5 14 41 10 37 51 32 65 46 61 8 15 19 16 44 31 42 19 46 66 25 26 58 60 5 19 18 69 53 20 40 45 27 24 41 32 23 57 56 62 10\n", "11\n5 6 4 2 9 7 6 6 6 6 7\n", "2\n2000 2000\n", "3\n500 501 502... | EASY | ['brute force', 'sortings', 'implementation'] | null | codeforces | ['Sorting', 'Implementation', 'Complete search'] | ['Sorting', 'Complete search'] | https://codeforces.com/problemset/problem/551/A | 2.0 seconds | null | null | 256.0 megabytes | null | 25,368 | 0 | (n, x) = (int(input()), list(map(int, input().split(' '))))
tmp = sorted(x, reverse=True)
for i in x:
print(tmp.index(i) + 1)
| # Question
Professor GukiZ likes programming contests. He especially likes to rate his students on the contests he prepares. Now, he has decided to prepare a new contest.
In total, n students will attend, and before the start, every one of them has some positive integer rating. Students are indexed from 1 to n. Let'... | |
This problem is different from the hard version. In this version Ujan makes exactly one exchange. You can hack this problem only if you solve both problems.
After struggling and failing many times, Ujan decided to try to clean up his house again. He decided to get his strings in order first.
Ujan has two distinct str... | [
"t = int(input())\nfor x in range(t):\n\tn = int(input())\n\ts = input()\n\tt = input()\n\ti = c = 0\n\ta = b = ''\n\twhile c < 4 and i < n:\n\t\tif s[i] != t[i]:\n\t\t\tc += 1\n\t\t\ta += s[i]\n\t\t\tb += t[i]\n\t\ti += 1\n\tif c == 2 and len(set(a)) == len(set(b)) == 1:\n\t\tprint('Yes')\n\telse:\n\t\tprint('No')... | {"inputs": ["4\n5\nsouse\nhouhe\n3\ncat\ndog\n2\naa\naz\n3\nabc\nbca\n", "10\n11\nartiovnldnp\nartiovsldsp\n2\naa\nzz\n2\naa\nxy\n2\nab\nba\n2\nza\nzz\n3\nabc\nbca\n16\naajjhdsjfdsfkadf\naajjhjsjfdsfkajf\n2\nix\nii\n2\noo\nqo\n2\npp\npa\n", "1\n2\nab\ncd\n", "1\n4\naacd\nbbdc\n", "1\n4\naabb\ncccc\n", "1\n2\nab\ncc\n",... | EASY | ['strings'] | null | codeforces | ['String algorithms'] | [] | https://codeforces.com/problemset/problem/1243/B1 | null | 2019-12-31 | null | null | null | 25,408 | 0 | t = int(input())
for x in range(t):
n = int(input())
s = input()
t = input()
i = c = 0
a = b = ''
while c < 4 and i < n:
if s[i] != t[i]:
c += 1
a += s[i]
b += t[i]
i += 1
if c == 2 and len(set(a)) == len(set(b)) == 1:
print('Yes')
else:
print('No')
| # Question
This problem is different from the hard version. In this version Ujan makes exactly one exchange. You can hack this problem only if you solve both problems.
After struggling and failing many times, Ujan decided to try to clean up his house again. He decided to get his strings in order first.
Ujan has two ... | |
You are given a rectangular board of M × N squares. Also you are given an unlimited number of standard domino pieces of 2 × 1 squares. You are allowed to rotate the pieces. You are asked to place as many dominoes as possible on the board so as to meet the following conditions:
1. Each domino completely covers two squa... | [
"(M, N) = map(int, input().split())\nd = M * N // 2\nprint(d)\n",
"a = list(map(int, input().split()))\na = a[1] * a[0]\nprint(a // 2)\n",
"(M, N) = [int(x) for x in input().split()]\nq = N % 2\nw = N // 2\nif q == 0:\n\ts = w * M\nelse:\n\tc = M // 2\n\ts = c + w * M\nprint(s)\n",
"(m, n) = map(int, input().... | {"inputs": ["2 6\n", "1 5\n", "3 6\n", "2 5\n", "3 16\n", "2 7\n", "3 10\n", "14 16\n", "1 16\n", "5 16\n", "4 4\n", "15 16\n", "5 7\n", "2 16\n", "2 2\n", "1 6\n", "1 1\n", "16 16\n", "14 15\n", "1 4\n", "2 14\n", "3 15\n", "2 3\n", "3 4\n", "11 13\n", "3 5\n", "3 14\n", "8 15\n", "15 15\n", "1 2\n", "1 15\n", "1 3\n"... | EASY | ['greedy', 'math'] | null | codeforces | ['Mathematics', 'Greedy algorithms'] | ['Greedy algorithms'] | https://codeforces.com/problemset/problem/50/A | 2.0 seconds | null | null | 256.0 megabytes | null | 25,237 | 0 | (M, N) = map(int, input().split())
d = M * N // 2
print(d)
| # Question
You are given a rectangular board of M × N squares. Also you are given an unlimited number of standard domino pieces of 2 × 1 squares. You are allowed to rotate the pieces. You are asked to place as many dominoes as possible on the board so as to meet the following conditions:
1. Each domino completely cov... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.