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

int main() {
  int n, g, v;
  cin >> n >> g >> v;
  int m = n / 5;
  ll total = (ll)g * m;
  long double ans = (long double)total / v;
  cout << fixed << setprecision(15) << ans << '\n';
  return 0;
}