instruction:
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:
luloouolouu
answer:
uolou


question:
tztzxzxtzxtzzt
answer:
tzzt


question:
mmmpmppjpj
answer:

mmm