#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <iomanip>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(int i = 0;i < n;++i)
#define M_PI 3.14159265359
int main() {
	long long n, g, v;
	cin >> n >> g >> v;
	long long how_great = (n/5);
	how_great *= g;
	double ans = (double)how_great / (double)v;
	cout <<fixed << setprecision(13) << ans << endl;
	cin >> n;
}