Please solve the programming task below using a self-contained code snippet in a markdown code block.

Given a string s, find the longest palindromic subsequence's length in s.
A subsequence is a sequence that can be derived from another sequence by deleting some or no elements without changing the order of the remaining elements.
 
Please complete the following python code precisely:
```python
class Solution:
    def longestPalindromeSubseq(self, s: str) -> int:
```