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 that are playing wii'. How many words start with the letter 'p' in the sentence.
Example Output: 2

Example Input: Sentence: 'a woman standing next to a surfboard at the ocean'. How many words start with the letter 't' in the sentence.
Example Output: 2

Example Input: Sentence: 'a calico cat on a wooden desk near a computer mouse'. How many words start with the letter 'a' in the sentence.
Example Output:
3