#include <iostream>
#include <stdint.h>
#include <iomanip>
using namespace std;

int main(){
	uint64_t n, g, v;
	cin >> n >> g >> v;
	n = n / 5;
	double ans1 = n * g / (double)v;
	cout << fixed << setprecision(20) << ans1 << endl;
	return 0;
}