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]: vnbvnvbnnvbn
[EX A]: nbvnvbn

[EX Q]: qgrqgqgqqg
[EX A]: qgqgq

[EX Q]: mgbgbgmgmbbmmm
[EX A]:
mgbgbgm