#define _GLIBCXX_DEBUG
#define ll long long
#define INF 1000000000;
#define INF_B 1000000000000000000;
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  ll N, G, V; cin >> N >> G >> V;
  N /= 5;
  ll NG = N*G;
  double ans = (double)NG / V;
  cout << fixed << setprecision(15);
  cout << ans << endl;
}