Longest Palindromic Subsequence

MEDIUM-HARD · C · 3000ms

Sabbir's team is compressing sensor-log strings and wants the longest palindromic PATTERN (subsequence, not necessarily contiguous) hidden in a log. Given a string S, print the length of its longest palindromic subsequence.

Input

One string S.

Output

Length of the longest palindromic subsequence.

Constraints

1 ≤ |S| ≤ 2000

Sample Input

bbbab

Sample Output

4
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Longest Palindromic Subsequence · DIU ContestHub