factorial

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int n= scanner.nextInt();
        scanner.nextLine();
        System.out.println(factorial(n));
    }

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

}