FactorialDivision

import java.util.Scanner;

public class FactorialDivision {

    static int fac(int n) {
        if (n == 0)
            return 1;
        return (n * fac(n - 1));
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = Integer.parseInt(scanner.nextLine());
        int b = Integer.parseInt(scanner.nextLine());
        System.out.printf("%.2f", (double)(fac(a) / fac(b)));
    }
}