using System;

using System.Text;

public class Program

{

    public static void Main()

    {

        string _s = "aaab";

        Console.WriteLine($"Compressed: {compress(_s)}");

    }

    public static string compress(string str){

        int finalLength=countCompression(str);

        if(finalLength > str.Length) return str;

        StringBuilder  sb= new StringBuilder(finalLength);

        int countConsecutive = 0;

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

            countConsecutive++;

            if(i+1 >= str.Length || str[i] != str[i+1]){

                sb.Append(str[i]);

                sb.Append(countConsecutive);

                countConsecutive =0;

            }

        }

        return sb.ToString();

    }

    private static int countCompression(string str){

        int compressedLength = 0;

        int countConsecutive = 0;

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

            countConsecutive++;

            if(i+1 >= str.Length || str[i] != str[i+1]){

                compressedLength += 1 + (countConsecutive.ToString()).Length;

                countConsecutive =0;

            }

        }

        return compressedLength;

    }

}