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 living room with hd tv chair and decorations'. How many words start with the letter 'r' in the sentence.
Example Output: 1

Example Input: Sentence: 'a man in vest and tie holding a cellphone'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'several beach umbrellas and beach chairs in the sand on a beach near the ocean'. How many words start with the letter 'b' in the sentence.
Example Output:
3