#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
#define pb push_back
#define mp make_pair
#define fi first
#define se second

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