using System;

public class Program

{

    static string compressedResult = "";

        public static void Main()

        {

            //string str1="a";

            string str1 = "aaabccccdd";

            //string str1 = "yyyyyzzzzzzzzzz";

            //string str1 = "abcd";

            //string str1 = "hhhccchhhccc";

            //string str1 = "aaabbaacccbb";

            int counter = 1;

​

            if (str1 != null && str1.Length > 1)

            {

                for (int i = 1; i <= str1.Length-1; i++)                        //starting loop from 2nd character to end

                {

                    if (str1[i - 1] == str1[i])                                 //comparing character to previous

                    {

                        counter++;                                              //increse counter if matches to previous

                        if (i == str1.Length-1)                                 //check if counter has been reached to end, if yes then compile result, if no continue

                            Program.computeResult(str1[i-1], counter);

                        else

                            continue;

                    }

                    else                                                        //character at cursor not matches to previous

                    {

                        Program.computeResult(str1[i - 1], counter);            //compute result for previous character

                        if (i == str1.Length - 1)                               //check if counter has been reached to end, if yes then compile result, if no continue by resetting counter

                            Program.computeResult(str1[i], counter);

                        else

                        {

                            counter = 1;                                        //reset counter for next character

                            continue;

                        }

                    }

                }

            }

            else

                compressedResult= str1;

            Console.WriteLine(str1);

            Console.WriteLine(compressedResult);

        }

        public static void computeResult(char str, int counter)

        {

            if (counter == 1)

            {

                compressedResult += str.ToString();

            }

            else

            {

                compressedResult += str.ToString() + counter.ToString();

            }

        }

}