Factorial

import java.util.Scanner;

class Scratch {
    public static void main(String[] args)
    {
        Scanner scan = new Scanner(System.in);
        int fac = scan.nextInt();
        int sum = 1;
        for(int i = 1;i <= fac; i ++) {
            sum *= i;
        }
        System.out.println(sum);
    }
}