#include <bits/stdc++.h>
/*
Problem: 10071 - Back to High School Physics
Link   : https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=1012

Solution by: Mohamed Hisham El-Banna

Gmail   : Mohamed00Hisham@Gmail.com
Github  : www.github.com/Mhmd-Hisham
LinkedIn: www.linkedin.com/in/Mhmd-Hisham
*/

using namespace std;

typedef signed long long ll;
typedef unsigned long long ull;

int v, t;

int main (){

    while( scanf("%d%d", &v, &t) != EOF){
        printf("%d\n", 2*v*t);
    }

    return 0;
}
/*
Sample input:-
-----------------
0 0
5 12

Sample output:-
-----------------
0
120

Resources:-
-------------

Explanation:
---------------

*/