import java.util.Scanner;

public class b {
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		long G = sc.nextLong();
		long V = sc.nextLong();
		long foo = N / 5;
		double tmp = (G * foo);
		double i_o = V;
		double bar = tmp / V;
		System.out.printf("%.12f\n", bar);
	}
}