Caesar Cipher Encryption

In this problem, you are required to implement a Caesar cipher with a fixed shift of \(3\). Given an input string, each alphabetical character should be shifted 3 positions forward, wrapping around the alphabet if necessary. Non-alphabetical characters remain unchanged.

For example, the letter 'a' becomes 'd', 'X' becomes 'A', and punctuation marks or digits are not affected.

Note: All formulas are written in LaTeX format if needed.

inputFormat

The input consists of a single line containing a string \(S\) (\(1 \leq |S| \leq 10^5\)), which may include letters, digits, spaces, and punctuation.

outputFormat

Output the encrypted string after applying the Caesar cipher with a shift of \(3\) to each alphabetical character.

abc

def