#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)
typedef long long ll;

ll N, G, V;

int main()
{
	cin.tie(0);
	ios::sync_with_stdio(false);

	while (cin >> N >> G >> V)
	{
		ll d = N / 5;

		double ans = (double)d * (double)G / (double)V;

		printf("%.10f\n", ans);
	}
}