import java.util.Scanner;

public class FactorialDivision {

    static double getFactorial (int n){
        int factorial = 1;
        if (n == 0){
            factorial = 1;
        }else {
            for (int i = 1; i <= n; i++) {
                factorial *= i;
            }
        }
        return factorial;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = Integer.parseInt(scanner.nextLine());
        int b = Integer.parseInt(scanner.nextLine());
            if (b!=0) {
                double number = getFactorial(a) / getFactorial(b);

                System.out.printf("%.2f", number);
            }
    }
}