#include <bits/stdc++.h>
using namespace std;
using pint = pair< int, int >;

int main()
{
    int n = 0, g = 0, v = 0;
    cin >> n >> g >> v;
    long double goen = n / 5.0;
    long double gas = goen * g;
    cout << fixed << setprecision( 12 ) << ( gas / v ) << endl;
}