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 man is carrying a large case with him'. How many words start with the letter 'w' in the sentence.
Example Output: 1

Example Input: Sentence: 'a black and white cat sits in a bathroom sink'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'a pole with the names of two streets'. How many words start with the letter 'n' in the sentence.
Example Output:
1