#include<iostream>
#include<iomanip>

int main() {
	long long N, G, V;
	double ans;
	std::cin >> N >> G >> V;
	N /= 5;
	G *= N;
	ans = static_cast<double>(G) / V;
	std::cout << std::fixed << std::setprecision(20) << ans << std::endl;
}