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 laptop and some computers on a desk'. How many words start with the letter 'd' in the sentence.
Example Output: 1

Example Input: Sentence: 'a couple of people sitting on a couch plays with a wii remote'. How many words start with the letter 'w' in the sentence.
Example Output: 2

Example Input: Sentence: 'a big double decker bus is driving around outside'. How many words start with the letter 'd' in the sentence.
Example Output:
3