using System;
 
public class Test
{
	public static void Main()
	{
		string[] inputs = {
			"3123124245252342345423523525235235",
			"9090909090909090",
			"727519727519727519"
		};
		foreach(string input in inputs)
			Console.WriteLine(string.Format("{0}: pattern {1}", input, Check(input)));
	}
 
	public static string Check(string s)
	{
		for(int i = 0; i<=s.Length / 2;i++)
		{
			string part = s.Substring(0,i+1);
			if((s.Length % part.Length) == 0)
			{
				string attempt = string.Empty;
				for(int k = 0; k < (s.Length / part.Length);k++)
					attempt += part;
				if(attempt == s)
					return part;
			}
		}
		return "not found";
	}
}

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