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: 'an indoor bathroom with reflective marble counter tops'. How many words start with the letter 'i' in the sentence.
Example Output: 1

Example Input: Sentence: 'the nine people smile as they sit at a dinner table'. How many words start with the letter 'a' in the sentence.
Example Output:
3