Palindrome Checker

The goal of this problem is to determine whether a given string (ignoring non-alphanumeric characters and case differences) is a palindrome. A string is a palindrome if it reads the same backward as forward after filtering out non-alphanumeric characters and converting all letters to lowercase.

Special conditions:

• If the input string is exactly None, then output Error: Null input not allowed.

Note that the validations for non-string types are not applicable since the input is always given as a string via STDIN.

Examples:

• Input: racecar → Output: Palindrome
• Input: A man, a plan, a canal: Panama → Output: Palindrome
• Input: Hello, World → Output: Not a Palindrome
• Input: None → Output: Error: Null input not allowed

inputFormat

The input consists of a single line containing a string. This string may include spaces, punctuation, and mixed cases. If the input string is exactly None, it should be treated as a null input.

outputFormat

Output a single line with one of the following responses:

• Palindrome if the input string (after filtering) is a palindrome.
• Not a Palindrome if it is not a palindrome.
• Error: Null input not allowed if the input is exactly None.

## sample

racecar

Palindrome