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: 'young lady sitting on a bicycle rickshaw talking on the phone'. How many words start with the letter 's' in the sentence.
Example Output: 1

Example Input: Sentence: 'a man wearing a straw hat and a black shirt'. How many words start with the letter 'a' in the sentence.
Example Output: 4

Example Input: Sentence: 'a close up of a persons pin on his suit'. How many words start with the letter 'p' in the sentence.
Example Output:
2