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.

Example Input: vfvvfmvvfv
Example Output: fvvf

Example Input: eqqqeeeqgqgg
Example Output: eqqqe

Example Input: sssqqssswww
Example Output:
sssqqsss