#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <bitset>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
using namespace std;
typedef long long ll;
typedef pair<int,int> pint;
typedef vector<int> vint;
typedef vector<pint> vpint;
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(ll i=0;i<(n);i++)
#define REP(i,n) for (int i=(n)-1;i>=0;i--)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define REPS(i,f,n) for (int i=(f)-1;i>=(n);i--)

int main(void){
	ll  n, g, v;
	cin >> n >> g >> v;
	int maisuu = n / 5;
	ll sum = g * maisuu;
	double ans = (double)sum / (double)v;
	printf("%.14f\n", ans);
	return 0;
}