String&Text - 23

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _23.ReplaceConsecutiveIdenticalLetters
{
    class ReplaceConsecutiveIdenticalLetters
    {
        /* Write a program that reads a string from the
         * console and replaces all series of consecutive
         * identical letters with a single one. Example:
         * "aaaaabbbbbcdddeeeedssaa"  "abcdedsa".*/


        static List<char> chars = new List<char>();
        static List<int> counts = new List<int>();


        static void Main()
        {
            // Console.WriteLine("Please enter sequence of chars:");
            string inputString = "aaaaabbbbbcdddeeeedssaat";// "aaatAaabbbb bcdddee@# eed125 ssaatt";// Console.ReadLine();

            string letters = "abcdefghijklmnopqrstuvwxyzABCDEFJHIGKLMNOPQRSTUVWXYZ";

            int count;

            Console.WriteLine("char-->count");
            for (int i = 0; i < inputString.Length; i++)
            {
                char currentChar = inputString[i];
                count = 1;
                if (letters.Contains(currentChar))
                {
                    if (i == inputString.Length - 1)
                    {
                        if (currentChar != inputString[inputString.Length - 2])
                        {
                            AddCharAndCount(currentChar, 1);
                            PrintCharToCount(currentChar, 1);
                        }
                        else
                        {
                            break;
                        }
                    }
                    else
                    {
                        for (int j = i + 1; j < inputString.Length; j++)
                        {
                            char currentY = inputString[j];
                            if (currentChar == inputString[j])
                            {
                                count++;
                            }
                            else
                            {
                                AddCharAndCount(currentChar, count);
                                PrintCharToCount(currentChar, count);
                                i = j - 1;
                                count = 1;
                                break;
                            }
                            if (j == inputString.Length - 1)
                            {
                                AddCharAndCount(currentChar, count);
                                PrintCharToCount(currentChar, count);
                                i = j - 1;
                            }
                        }
                    }
                }
            }

            Console.WriteLine();
            Console.WriteLine("or");
            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < chars.Count; i++)
            {
                builder.Append(chars[i]);
                Console.WriteLine("{0} --> {1}", chars[i], counts[i]);
            }
            Console.WriteLine(builder.ToString());
        }

        private static void AddCharAndCount(char currentChar, int count)
        {
            chars.Add(currentChar);
            counts.Add(count);
        }
        static void PrintCharToCount(char charOfString, int count)
        {
            Console.WriteLine("{0} --> {1}", charOfString, count);
        }
    }
}