using System;

public class Program

{

    public static string GetMiddle(string s)

    {

        var trimmed = String.Empty;

        int length = s.Length;

        var middleOfString = length/2;

        if(length == 1)

        {

            trimmed = s;

            return trimmed;

        }

        //if length is odd

        if((length % 2) != 0)

            trimmed = s.Substring(middleOfString - 1, 3);

        else

            trimmed = s.Substring(middleOfString - 1, 2);

        return trimmed;

    }

    public static void Main()

    {

        var test = "DOTUN";

        var getMiddleChar = GetMiddle(test);

        Console.WriteLine(getMiddleChar);

    }

}