Palindrome Check

Determine whether a given string is a palindrome. A string is considered a palindrome if, after removing all non-letter characters and ignoring case, it reads the same forwards and backwards.

In mathematical terms, if we let \( s' \) be the string obtained after filtering out all characters except letters and converting them to lowercase, then \( s' \) is a palindrome if:

\[ \forall i,\quad s'[i] = s'[n-i-1], \quad \text{where } n = |s'| \]

Your task is to read a string from standard input (stdin), determine if it is a palindrome under these rules, and print True if it is, or False otherwise to standard output (stdout).

inputFormat

The input consists of a single line containing the string to be checked.

Input is provided via standard input (stdin).

outputFormat

Output a single line: True if the string is a palindrome according to the rules, otherwise False.

The output should be written to standard output (stdout).

A man, a plan, a canal, Panama.

True