You are given a string s.

You can perform the following operation on the string any number of times:

Choose an index i in s such that there is at least one identical character to the left of i and at least one identical character to the right of i.
Remove the closest identical character to the left of i.
Remove the closest identical character to the right of i.

Return the minimum possible length of s that can be achieved after performing any number of operations.

Constraints:

• $1 \leq$ s.length $\leq 2 imes 10^5$

• s consists only of lowercase English letters.

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.