import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    double N = sc.nextDouble();
    double G = sc.nextDouble();
    double V = sc.nextDouble();
    N = N / (double)5;
    G = G * N;
    double ans = G / V;
    System.out.println(ans);
  }
}