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]: mxxxmxxdmmxdxx
[A]: mxxxm


[Q]: tttcccoctoo
[A]: ttt


[Q]: aaddddbdbbaabbd
[A]:
dbbaabbd