Caesar Cipher Encryption and Decryption

This problem involves implementing the classic Caesar Cipher. Given an operation, a shift value, and a message, you must either encrypt or decrypt the message according to the Caesar Cipher method. In the encryption process, each letter is replaced by its counterpart shifted by a fixed number of positions in the alphabet. For decryption, the process is reversed.

For a letter c, if it is uppercase or lowercase, the cipher works as follows:

\( c' = (c - base + shift) \mod 26 + base \)

where base is \( ord('A') \) for uppercase letters and \( ord('a') \) for lowercase letters. Non-alphabetical characters remain unchanged.

inputFormat

The input will be provided through stdin in the following order, each on a new line:

1. A string indicating the operation, either ENCRYPT or DECRYPT.
2. An integer representing the shift value.
3. A string representing the message. This message may include spaces, punctuation, or digits.

outputFormat

Output the encrypted or decrypted message on a single line to stdout.

ENCRYPT
3
Hello, World!

Khoor, Zruog!