uva_cpp_clean/10071/10071-15.cpp

/*
    數學?
*/
#include <iostream>

using namespace std;

int main() {
    cin.tie(0);
    ios_base::sync_with_stdio(0);

    int v, t;
    while (cin >> v >> t)
        cout << 2 * v * t << "\n";

    return 0;
}