10071 - Back to High School Physics

#include <iostream>
#include <set>
#include<vector>
#include<string>
#include<sstream>
#include<algorithm>
#include<map>
using namespace std;

int main()
{
	int a, b;
	while (cin >> a >> b) {
		cout << 2 * a * b << endl;
	}
}