Datasets:

slayone
/

uva_spoj_raw

/*
    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;
}

	/*
	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;
	}