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.

tbttvbvvbbbvbtv
vbbbv
The given string is 'tbttvbvvbbbvbtv'. The longest palindrome in this string is 'vbbbv', which has 5 characters..