#include <bits/stdc++.h>

using namespace std;

#define LL long long

int main() {
    LL n, g, v;
    cin >> n >> g >> v;
    LL nn = n / 5;

    cout << fixed << setprecision(13);
    cout << (double) (nn * g) / (double) v << endl;
    return 0;
}