벡준 10872

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class Main10872 {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int N = Integer.parseInt(br.readLine());
		
		System.out.println(factorial(N));
		
	}
	
	public static int factorial(int n){
		if(n  <= 1){
			return 1;
		}else{
			return factorial(n-1) * n;
		}
	
	}

}