#include<iostream>
#include<string>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<cstring>
#include<map>
#include<vector>
#include<queue>
#include<climits>
using namespace std;
typedef long long int ll;

int main(){

	ll n, g, v;
	cin >> n >> g >> v;
	n/=5;
	n*=g;
	cout << setprecision(25) << (double)n/(double)v << endl;
  
  return 0;
}