using System;

public class Program

{

    public static void Main()

    {

            int i = 1;

            int t = 1;

            Console.Write("Tinh tich T(n). voi n = ");

            int n= Convert.ToInt32( Console.ReadLine());

            while (i <=n)

            {

              t *= i;

              i++;

            }

            Console.WriteLine(t);

    }

}