import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import static java.lang.System.in;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String[] inputs = reader.readLine().split(" ");
        long N = Long.parseLong(inputs[0]);
        long G = Long.parseLong(inputs[1]);
        long V = Long.parseLong(inputs[2]);

        long numOf5Yen = N / 5;
        long gas = numOf5Yen * G;
        System.out.println((double)gas / V);
    }
}