A sentence consists of tokens separated by one or more spaces. A token is defined as a contiguous sequence of non-space characters.

A token is considered a valid word if it satisfies all of the following conditions:

• It does not contain any digits, consisting only of lowercase English letters, hyphens '-', and punctuation marks ('!', '.', and ',').

• It contains at most $1$ hyphen '-'. If present, the hyphen must be surrounded by lowercase English letters on both sides.

• It contains at most $1$ punctuation mark. If present, the punctuation mark must be at the very end of the token.

Given a string sentence, return the number of valid words in sentence.

Constraints:

• $1 \leq$ sentence.length $\leq 1000$

• sentence only contains lowercase English letters, digits, ' ', '-', '!', '.', and ','.

• There will be at least $1$ token.

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.