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: yyxmmxmmmxmyyxm

SOLUTION: mxmmmxm

PROBLEM: tdtedtettddee

SOLUTION: tdt

PROBLEM: zkzzkzkzkzzz

SOLUTION:
zzkzkzkzz