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 pitcher throwing a baseball during a baseball game'. How many words start with the letter 'b' in the sentence.
Example Output: 2

Example Input: Sentence: 'a large group of men with bats in a dugout'. How many words start with the letter 'g' in the sentence.
Example Output: 1

Example Input: Sentence: 'a polar bear walks over the rocks in his zoo exhibit'. How many words start with the letter 'e' in the sentence.
Example Output:
1