#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>
#include <bitset>
#include <cassert>

using namespace std;
using ll = long long;
const long long INF = 1LL << 60;
const long long MOD = 1000000007;


int main() {

    long N, G, V;
    cin >> N >> G >> V;

    long T = (N/5)*G;

    cout << fixed << setprecision(12) << (double)T/(double)V << endl;

    return 0;
}