Valid Palindrome Check

This problem requires you to determine whether a given string is a valid palindrome. A string is considered a palindrome if, after converting all uppercase letters to lowercase and removing all non-alphanumeric characters, it reads the same forward and backward.

Note: The check should only consider letters and digits, and should ignore any spaces or punctuation. For example, the string "A man, a plan, a canal: Panama" is a palindrome.

The mathematical formulation of the check can be represented as:

\( \text{filtered}(s) = s' \quad \text{and} \quad s' = reverse(s') \)

where \( s' \) is the string obtained by retaining only the lowercase alphanumeric characters of the original input \( s \).

inputFormat

The input is provided via stdin as a single line containing a string s.

Input format:

s

outputFormat

Output a single line to stdout which is either True if the provided string is a palindrome, or False otherwise.

Output format:

result

## sample

A man, a plan, a canal: Panama

True