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]: yiyqiqyyiyyy
[EX A]: yqiqy

[EX Q]: nnnnyyunyuyyuny
[EX A]: nnnn

[EX Q]: ppzzznnnpnnzp
[EX A]:
nnpnn