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 counter topped with vases in front of a window'. How many words start with the letter 'w' in the sentence.
Example Output: 2

Example Input: Sentence: 'a msall bus going down a road with a street sign'. How many words start with the letter 'd' in the sentence.
Example Output: 1

Example Input: Sentence: 'a red double decker bus parked next to a brick building'. How many words start with the letter 'r' in the sentence.
Example Output:
1