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 small airplane sitting on top of a runway'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'a man pops a skateboard trick at a skate park'. How many words start with the letter 'a' in the sentence.
Example Output:
4