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 cat sitting next to boxes of produce sitting in front of a store'. How many words start with the letter 's' in the sentence.
Example Output: 3

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: 'some very pretty giraffes standing by a big fence'. How many words start with the letter 'f' in the sentence.
Example Output:
1