#include <bits/stdc++.h>
using namespace std;

int main()
{
    double n, m, x;
    cin >> n >> m >> x;
    if (m / n * x == 60)
    {
        cout << "60.0" << endl;
        return 0;
    }
    cout << fixed << setprecision(2) << m / n * x << endl;
    return 0;
}