Given two strings a and b, return the length of the longest uncommon subsequence between them. If no uncommon subsequence exists, return $-1$.

An uncommon subsequence between two strings is defined as a string that is a subsequence of one string but not a subsequence of the other.

Note: A subsequence of a string is a new string generated from the original string by deleting zero or more characters without changing the relative order of the remaining characters.

Constraints:

• $1 \leq$ a.length, b.length $\leq 100$

• a and b consist 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.