Valid Palindrome with Alphanumeric Filtering

A phrase is a **palindrome** if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers. Given a string `s`, return `true` if it is a **palindrome**, or `false` otherwise. ### Constraints - `1 <= s.length <= 2 * 10^5` - `s` consists only of printable ASCII characters. ### Input Format A single line containing the string `s`. ### Output Format Print `true` if `s` is a valid palindrome, otherwise `false`.