class Solution:
    def longestPalindrome(self, s: str) -> str:
        if len(s) <= 1:
            return s
        

        dp = [[False for _ in range(len(s))] for _ in range(len(s))]

        max_length = 1
        max_string = s[0]
        for i in range(len(s)):
            dp[i][i] = True
            for j in range(i):
                if s[j] == s[i] and (i-j <= 2 or dp[j+1][i-1]):
                    dp[j][i] = True
                    if i-j+1 > max_length:
                        max_length = i-j+1
                        max_string = s[j:i+1]
        return max_string