using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        // Regular Expression

        /*

        Can be up to 9 characters in length, comprising:

        AAA - one to three letters [A-Z per character]

        #### - one to four integers [0-9 per digit]

        Suffix - R, RR, BR, CA (or none defined)

        */

        // ^[a-zA-Z]{1,3}[0-9]{1,4}([rR]{1,2}|[bB][rR]|[cC][aA])?$

        var regex =  @"^[a-zA-Z]{1,3}[0-9]{1,4}([rR]{1,2}|[bB][rR]|[cC][aA])?$";

        var foo = "The quick brown fox jumped over the lazy dog";

        var match = Regex.Match(foo, regex, RegexOptions.IgnoreCase);

        Console.WriteLine(match.Success);

        /*

        foo = "abcdefghi";

        match = Regex.Match(foo, regex, RegexOptions.IgnoreCase);

        Console.WriteLine(match.Success);   

        foo = "ABC1234CA";

        match = Regex.Match(foo, regex, RegexOptions.IgnoreCase);

        Console.WriteLine(match.Success);

        foo = "ARN1234CA";

        match = Regex.Match(foo, regex, RegexOptions.IgnoreCase);

        Console.WriteLine(match.Success);

        foo = "Sign V1 230221";

        match = Regex.Match(foo, regex, RegexOptions.IgnoreCase);

        Console.WriteLine(match.Success);

        */

    }

}