package no379;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		double g = sc.nextDouble();
		double v = sc.nextDouble();
		
		double yomenai = (n / 5) * g;
		System.out.println(String.format("%.13f",yomenai / v));
	}

}