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: 'a woman is standing in the kitchen using her phone'. How many words start with the letter 'w' in the sentence.
Example Output: 1

Example Input: Sentence: 'two people playing frisbee on the beach on a sunny day'. How many words start with the letter 't' in the sentence.
Example Output: 2

Example Input: Sentence: 'a young man skating alone on a sidewalk at the park'. How many words start with the letter 's' in the sentence.
Example Output:
2