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.

[EX Q]: xxxrxxrrxrxoo
[EX A]: xxrxx

[EX Q]: smsmggggsmsmsms
[EX A]: smsmsms

[EX Q]: pzmpmppzzzz
[EX A]:
zzzz