using System;
using System.Collections;

namespace MyCompiler {
    class Program {
        public static void Main(string[] args) {
            ArrayList Memo = new ArrayList();
            int n = Console.ReadLine();
            ArrayList.Add(1);
            for (int i = 1; i <= n; i++) {
                ArrayList.Add((int)Memo[i-1]*i);
            }
            Console.WriteLine((int)Memo[i]);

            Console.WriteLine("idk");
        }
    }
}