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 couple of people are riding horses in a village'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'a group of people sitting at a restaurant table'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'woman posing for the camera in front of a microwave'. How many words start with the letter 'c' in the sentence.
Example Output:
1