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]: twwntwnnnttwnw
[A]: nnn


[Q]: mmmmmmmbmbbb
[A]: mmmmmmm


[Q]: iiiiqqiiiiii
[A]:
iiiiqqiiii