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: 'different cars on the streets in a city setting'. How many words start with the letter 'i' in the sentence.
Example Output: 1

Example Input: Sentence: 'a young boy hits a baseball during a game'. How many words start with the letter 'd' in the sentence.
Example Output: 1

Example Input: Sentence: 'a person riding a skate board on a street'. How many words start with the letter 'a' in the sentence.
Example Output:
3