In this task you will be given a string and you should find the longest substring that is a palindrome. A palindrome is a string that is the same backwards as it is forwards. If the shortest possible palindrome is length 1 you should return the first character.

Input: Consider Input: wywywwwswssssy

Output: wywyw


Input: Consider Input: oppoioiopio

Output: poioiop


Input: Consider Input: jjttvvttjttj


Output: jttvvttj