#45623: F = Gm1 * m2 / (r ** 2)
chen971023@gmail.com
(ZiaynGZiyaNG)
#include <iostream>
using namespace std;
int main()
{
int m1, m2, r;
cin >> m1 >> m2 >> r;
cout << (m1 * m2 * 6) / (r * r);
}