In this task, you need to count the number of words in a sentence that start with the given letter. Answer with numbers and not words.

Example Input: Sentence: 'two men on motorcycles and wearing helmets'. How many words start with the letter 'w' in the sentence.
Example Output: 1

Example Input: Sentence: 'a couple of hot dogs and napkins on a table'. How many words start with the letter 'h' in the sentence.
Example Output: 1

Example Input: Sentence: 'a red and white stop sign and some bushes and trees'. How many words start with the letter 'a' in the sentence.
Example Output:
4