#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

//#include<bits/stdc++.h>



using namespace std;




int main() {

	unsigned long long int a;
	double b,c;
	cin>>a>>b>>c;
	a/=5;
	double w=a;
	cout<<setprecision(50);
	cout<<(double)w*b/c<<endl;

	return 0;
}