TASK DEFINITION: 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.
PROBLEM: yybbkyybybkykk

SOLUTION: yby

PROBLEM: vvvffvfuvuufu

SOLUTION: vffv

PROBLEM: zvvzzkvvkzkkv

SOLUTION:
zkvvkz