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.
--------
Question: tztzxzxtzxtzzt

Answer: tzzt


Question: tttttfttfttff

Answer: ttfttftt


Question: ytmyyymmmmymmmt

Answer:
mmmymmm