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 giraffes that are walking around'. How many words start with the letter 'c' in the sentence.
Example Output: 1

Example Input: Sentence: 'people all eating together and pretending to like each other'. How many words start with the letter 'p' in the sentence.
Example Output: 2

Example Input: Sentence: 'an outdated television set with a modern device on top of it'. How many words start with the letter 's' in the sentence.
Example Output:
1