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 putting a protective covering over a large tv screen'. How many words start with the letter 'l' in the sentence.
Example Output: 1

Example Input: Sentence: 'a horse pulling a carriage with people in the snow'. How many words start with the letter 'a' in the sentence.
Example Output: 2

Example Input: Sentence: 'an assortment of fruits and vegetables for sale  at a market'. How many words start with the letter 'v' in the sentence.
Example Output:
1