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]: vnbvnvbnnvbn
[A]: nbvnvbn


[Q]: rrrrrpprrrrp
[A]: rrrrpprrrr


[Q]: bsbskbsbsbkkb
[A]:
kbsbsbk