using System;

public class Program

{

    public static string FindLarge3DigitNum(string num) {

        string result = "";

​

        for (int i = 0; i < num.Length - 2; i++)

        {

            string curr = num.Substring(i, 3);

            if (num[i] == num[i + 1] && num[i + 1] == num[i + 2] && string.Compare(result, curr) < 0)

            {

                result = curr;

            }

        }

​

        return result;

    }

    public static void Main()

    {

        Console.WriteLine("UniLecs");

        // tests

        Console.WriteLine(FindLarge3DigitNum("2300019")); // 000

        Console.WriteLine(FindLarge3DigitNum("5777144449")); // 777

    }

}