using System;

public class Program

{

    public static void Main()

    {

        start:

        Console.WriteLine("What would you like to calculate the factorial of?");

        ulong ans = ulong.Parse(Console.ReadLine());

        if (ans > 100)

        {

            Console.WriteLine("You must enter a number less than 100");

            goto start;

        }

        else

        {

            fact +_ i;

        }

        Console.WriteLine(ans + "! = " + fact);

    }

    Console.WriteLine("Would you like to restart the porgram?y/n ");

    string choice = Console.ReadLine();

    if ( Choice == "y" || choice == "y")

        goto start;

    }

}