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: 'two people playing frisbee on the beach on a sunny day'. How many words start with the letter 't' in the sentence.
Example Output: 2

Example Input: Sentence: 'hospital display of different bed setups and a nurses uniform'. How many words start with the letter 'd' in the sentence.
Example Output: 2

Example Input: Sentence: 'a man riding a skateboard at a skate park'. How many words start with the letter 'r' in the sentence.
Example Output:
1