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: 'three groups of yellow flowers in vases on table'. How many words start with the letter 't' in the sentence.
Example Output: 2

Example Input: Sentence: 'a couple of kids are sitting in the grass'. How many words start with the letter 'a' in the sentence.
Example Output: 2

Example Input: Sentence: 'a view of a living room with a couch up against the wall near two windows'. How many words start with the letter 'w' in the sentence.
Example Output:
3