using System;

​

namespace CaesarCipher

{

  class Program

  {

    static void Main(string[] args)

    {

​

​

      Encrypt(Console.ReadLine());

​

​

​

​

    }

      static void Encrypt(string plainMessage){

      plainMessage = plainMessage.ToLower();

      char[] alphabet = new char[] {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};

​

      char[] secretMessage = plainMessage.ToCharArray();

      char[] encryptedMessage = new char[secretMessage.Length];

​

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

        char secretCharacter = secretMessage[i];

        int alphabetPosition = Array.IndexOf(alphabet, secretCharacter);

        char newCharacter = alphabet[(alphabetPosition + 3) % 26];

        encryptedMessage[i] = newCharacter;

        }

        string encryptedOutput = String.Join("", encryptedMessage);

        Console.WriteLine(encryptedOutput);

      }

  }

}