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.

Example Input: eqqqvevvvveee
Example Output: evvvve

Example Input: sssrrkkrrrssrk
Example Output: rrkkrr

Example Input: lhlloohhololhl
Example Output:
ohho