using System;

public class Program

{

    public static void Main()

    {

        int num1=0;

        int factrialop=1;

        num1=Convert.ToInt32(Console.ReadLine());

        while(num1!=1)

        {

            factrialop= factrialop*num1;

            num1--;

        }

        Console.WriteLine(factrialop);

    }

}