import java.util.Scanner;

public class FactorialDivision {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int first = Integer.parseInt(scanner.nextLine());
        int second = Integer.parseInt(scanner.nextLine());

        System.out.printf("%.2f", (double) factorial(first) / factorial(second));
    }

    private static int factorial(int n) {
        if (n == 0)
            return 1;
        else
            return (n * factorial(n - 1));
    }
}