using System;
using System.Linq;
using System.Collections.Generic;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            int number = int.Parse(Console.ReadLine());

            List<int> numbers = new List<int>();
            int factorial = 1;

            for (int i = 1; i <= number; i++)
            {
                numbers.Add(i);
            }

            for (int i = 0; i < numbers.Count; i++)
            {
                factorial = factorial * numbers[i];
            }
            Console.WriteLine(factorial);
        }
    }
}