Hi, here's your problem today. This problem was recently asked by Twitter:

A palindrome is a sequence of characters that reads the same backwards and forwards. Given a string, s, find the longest palindromic substring in s.

Example:
Input: "banana"
Output: "anana"

Input: "million"
Output: "illi"

<pre lang=py>
class Solution: 
    def longestPalindrome(self, s):
      # Fill this in.
        
# Test program
s = "tracecars"
print(str(Solution().longestPalindrome(s)))
# racecar
</pre>