Caesar Cipher Decryption

In this problem, you are given an integer n (where 0 ≤ n ≤ 25) and an encrypted message. The message is encoded using the Caesar cipher, meaning each letter in the original message has been shifted forward by n positions in the alphabet. Your task is to decrypt the message by shifting each letter backwards by n positions.

The decryption formula is given by: $$ D(c) = ((c - \text{'a'} - n) \mod 26) + \text{'a'} $$ where c is the ASCII value of the encrypted character. Note that spaces remain unchanged.

inputFormat

The input consists of two lines:

• The first line contains an integer n, the shift value.
• The second line contains the encrypted message, composed only of lowercase English letters and spaces.

outputFormat

Output the decrypted message as a single line.

3
khoor zruog

hello world