Given a string s consisting only of letters 'a' and 'b'. In a single step you can remove one palindromic subsequence from s.
Return the minimum number of steps to make the given string empty.
A string is a subsequence of a given string, if it is generated by deleting some characters of a given string without changing its order.
A string is called palindrome if is one that reads the same backward as well as forward.
Example 1:
Input: s = "ababa"
Output: 1
Explanation: String is already palindrome
Example 2:
Input: s = "abb"
Output: 2
Explanation: "abb" -> "bb" -> "". 
Remove palindromic subsequence "a" then "bb".
Example 3:
Input: s = "baabb"
Output: 2
Explanation: "baabb" -> "b" -> "". 
Remove palindromic subsequence "baab" then "b".
Example 4:
Input: s = ""
Output: 0
Constraints:
0 <= s.length <= 1000
s only consists of letters 'a' and 'b'
class Solution:
    def removePalindromeSub(self, s: str) -> int:
        if not s:
            return 0
        elif s == s[::-1]:
            return 1
        else:
            return 2

class Solution:
    def removePalindromeSub(self, s: str) -> int:
        if not s:
            return 0
        elif s == s[::-1]:
            return 1
        else:
            return 2
