#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define SZ(n) (int)(n).size()
#define ALL(n) (n).begin(), (n).end()
#define MOD % 1000000007
using namespace std;
typedef long long LL;
typedef vector<int> VI;

int main() {
	double n, g, v;
	cin >> n >> g >> v;
	LL ans = floor(n / 5) * g;
	cout << setprecision(12) << fixed << ans / v << endl;
	return 0;
}