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:
oxoxoaoxaaxxoaa
answer:
oxoxo


question:
hooohhoohoeoe
answer:
oohhoo


question:
nnsnnsnnsnnnnn
answer:

nnsnnsnnsnn