Given a string s consisting of characters 'a' and 'b'.

In one operation, you can select any contiguous substring of s that contains an equal number of 'a' and 'b' characters and delete it. The remaining left and right segments are then concatenated together.

Return the minimum possible length of s after performing any number of such operations.

Constraints:

• $1 \leq$ s.length $\leq 10^5$

• s[i] is either 'a' or 'b'.

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.