package Deom1;
import java.math.BigInteger;
import java.util.Scanner;
import java.util.SortedMap;

public class lx {
    public static void main(String [] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        sc.close();
        BigInteger b = new BigInteger("1");
        for (int i = 2;i <= n;i ++){
            b = new BigInteger(i + "").multiply(b);
        }
        System.out.println(b);
    }
}