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 man standing over a sheet cake on top of a table'. How many words start with the letter 's' in the sentence.
Example Output: 2

Example Input: Sentence: 'a plate with potato pancakes and a fork'. How many words start with the letter 'p' in the sentence.
Example Output: 3

Example Input: Sentence: 'some towels and stuff are on a bed'. How many words start with the letter 'a' in the sentence.
Example Output:
3