using System;

​

public class Program

{

    public static void Main()

    {

        var word = "\u0301удё";

        for (int i = 0; i < word.Length; i++)

        {

            var firstChar = (i == 0);

            var lastChar = (i == word.Length - 1);

            if (firstChar)

            {

                Console.WriteLine(word[i] + " - firstchar");

            }

​

            if (!firstChar && !lastChar) //converting letters between first and last one.

            {

                Console.WriteLine(word[i] + " - in the middle char");

            }

​

            if (lastChar) // real first char

            {

                Console.WriteLine(word[i] + " - lastchar");

            }

        }

    }

}