using System;

public class Program

{

    public static void Main()

    {

        int factorial=1,number;

        Console.WriteLine("enter a number for factorial to check");

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

        for( ;number>0;number--)

        {

            factorial=factorial*number;

        }

        Console.WriteLine("the factorial of number is {0}",factorial);

    }

}