using System;

​

class Program

{

    static string ReverseString(string text)

    {

        if (text.Length <= 1)

            return text;

        return ReverseString(text.Substring(1)) + text[0];

    }

​

    static void Main()

    {

        string input = "Merhaba";

        string reversed = ReverseString(input);

        Console.WriteLine(reversed); // abahreM

    }

}

​