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 black and white photo of a man in the street feeding cats and dogs'. How many words start with the letter 'a' in the sentence.
Example Output: 4

Example Input: Sentence: 'a person is standing by a pier near a fire hydrant'. How many words start with the letter 'p' in the sentence.
Example Output: 2

Example Input: Sentence: 'a baseball player stands deep in the outfield'. How many words start with the letter 'a' in the sentence.
Example Output:
1