using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.IO;
using System.Text;

public class Test
{
	public static void Main()
	{
		string phoneNumber = "1122"; // "1122" failed
        Dictionary<string, string> subPatterns = new Dictionary<string, string>();
        subPatterns[@"(?<1>\d)\k<1>(?<2>\d)\k<2>"] = "abba";
        subPatterns[@"(?<1>\d)(?<2>\d)\k<2>\k<1>"] = "aabb";
        string pattern = string.Join("|", subPatterns.Select(e => e.Key));
                        
        foreach (Match m in Regex.Matches(phoneNumber, pattern))
        {               
            if (m.Success)
            {
                Console.WriteLine("TRUE");
            }               
        }
	}
}