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.

[Q]: xxxrxxrrxrxoo
[A]: xxrxx


[Q]: xxhxhxxhhxx
[A]: xxhxhxx


[Q]: rsirrisrssrr
[A]:
rsirrisr