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 that has a toilet and window in it'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'three people in suits are standing and holding surfboards'. How many words start with the letter 's' in the sentence.
Example Output: 3

Example Input: Sentence: 'a picture of a very clean bed in the room'. How many words start with the letter 'r' in the sentence.
Example Output:
1