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: ssnjnjssjnnn
Example Output: njssjn

Example Input: iicicsscscc
Example Output: cssc

Example Input: zqkqqkqqqzkzk
Example Output:
qkqqkq