#include <iostream>
#include <stdio.h>
#include <math.h>
#include <vector>
#include <algorithm>
using namespace std;

int main(){

	int n,g,v;
	cin >> n >> g >> v;

	int f = n/5;

	double ans=0.0;
	ans = f*1.0;
	ans *= g;
	ans /= v;
	printf("%.15lf\n",ans);

}