#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>

using namespace std;



int main() {
    long long n, g, v;
    cin >> n >> g >> v;
    int f = n / 5;
    double gas = f * g;
    printf("%.12f\n", gas / v);
}