백준 #27433번 팩토리얼 2

import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		long mul = 1;
		for(int i = 1; i <= n; i++) {
			mul *= i;
		}
		
		System.out.println(mul);
		sc.close();
	}
}