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:
snnynnnyyy
answer:
nnynn


question:
ntgtnngtggttt
answer:
ntgtn


question:
vqqfffffqf
answer:

qfffffq