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 bathroom with a toilet with a blue seat'. How many words start with the letter 'b' in the sentence.
Example Output: 2

Example Input: Sentence: 'a photo of a waterway with several boats along the shore'. How many words start with the letter 'w' in the sentence.
Example Output: 2

Example Input: Sentence: 'a number of older people sitting at a table with wine glasses'. How many words start with the letter 'o' in the sentence.
Example Output:
2