Palindrome Checker

Given an input string, your task is to determine whether it is a palindrome or not. A palindrome is a string that reads the same backward as forward, after removing all non-alphanumeric characters and ignoring letter case. For example, "A man, a plan, a canal, Panama!" is a palindrome.

The input string may include letters, digits, punctuation marks, and whitespace. An empty string or a string that only contains non-alphanumeric characters should be considered a palindrome.

inputFormat

The input consists of a single string. This string may span multiple lines and can contain letters, digits, punctuation, and whitespace.

outputFormat

Output either True if the cleaned string is a palindrome or False otherwise. The output should be printed to stdout.

A man, a plan, a canal, Panama!

True