using System;
using System.Text.RegularExpressions;
					
public class Program
{
	public static void Main()
	{
		var hasRepeatedCharacter = new Regex(@"^([0-9]+)\1$");
		
		string text = "123123";
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
		
		text = "1233321";
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
		
		text = "3311";
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
		
		Console.WriteLine("Testing other regex:");
		hasRepeatedCharacter = new Regex(@"^([0-9]*)([0-9]+)\2([0-9]*)$");
		
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
		
		text = "31313100";
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
		
		text = "00313131";
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
		
		text = "11";
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
		
		text = "123456";
		Console.WriteLine($"Valid {text}: {hasRepeatedCharacter.IsMatch(text)}");
	}
}