Decode the Encrypted Message

You are given an encoded message s which consists solely of lowercase English letters and spaces, and an integer n which indicates how many positions each letter has been shifted forward (using a Caesar cipher). Your task is to decode the original message by shifting each letter backward by n positions in the alphabet.

The decoding follows the formula:

$$ c_{decoded} = ((c - 'a' - n) \mod 26) + 'a' $$

where c is the ASCII code of the current character. Note that spaces should remain unchanged, and if n is larger than 26, then effectively you must use n \mod 26 since a shift of 26 leads to no change.

inputFormat

The input is read from standard input and consists of two lines:

• The first line contains an integer n representing the shift amount.
• The second line contains the encoded message s, a string of lowercase letters and spaces.

outputFormat

Output the decoded message to standard output.

3
khoor zruog

hello world