using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        bool valid = true;

        string []digits = ["0","1","2","3","4","5","6","7","8","9"];

        Console.WriteLine("Please enter your car Registration");

        String Registration = Console.ReadLine();

        string letter2 = Registration;

        String Answer = letter2.Substring(0,1);

        foreach (string num in digits)

        { Answer = num;

          valid = false;

        Console.WriteLine("Please enter your car Registration");

        }Console.ReadLine();

        valid = true;

         if(valid == true)

         { valid = true;

        String Answer2 = letter2.Substring(1,1);

        foreach(string num2 in digits)

        {Answer2 = num2; 

        valid = false;  

        Console.WriteLine("Please enter your Registration again.");

        }Console.ReadLine(); }

        String Answer3 = letter2.Substring(2,1);

        foreach( string num3 in digits)

        { if( Answer3 == num3)

        {Console.ReadLine();}

        }

         Console.ReadLine();

    }

}

​