using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Please, insert the message");

        string message = Console.ReadLine();

        string result = Decrypt.ReadMessage(message);

        Console.WriteLine("Decrypting...");

        Console.WriteLine("Decrypted message: " + result);

    }

}

​

public static class Decrypt

{

    public static string[] PrepareMessage(string message){

        string[] binArray = message.Split(' ');

        int index = 0;

        foreach (string bin  in binArray){

            binArray[index] = StringManipulate.InvertLastTwo(binArray[index]);

            binArray[index] = StringManipulate.ChangeEachFour(binArray[index]);

            index++;

        }

        return binArray;

    }

    public static string ReadMessage(string message){

        string[] binArray = PrepareMessage(message);

        return Binary.Interpret(binArray);

    }

}

​

​

public static class StringManipulate

{

    public static string InvertLastTwo(string oldString){

        string start = oldString.Substring(0,6);

        string char6 = oldString[6] == '0' ? "1" : "0";

        string char7 = oldString[7] == '0' ? "1" : "0";

        string newString = start + char6 + char7;

        return newString;

    }

    public static string ChangeEachFour(string oldString){

        string newString = oldString.Substring(4,4) + oldString.Substring(0,4);

        return newString;

    }

}

​

public static class Binary

{

    public static string Interpret(string[] binaryArray){

        string newString = "";

        foreach(string letter in binaryArray){

            newString += (char)Convert.ToInt32(letter,2);

        }

        return newString;

    }

}