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 white sink and toilet in a wood floored bathroom'. How many words start with the letter 't' in the sentence.
Example Output: 1

Example Input: Sentence: 'zebras and antelopes in a field of dried grass'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'a bunch of chickens are gathered in someones yard'. How many words start with the letter 'b' in the sentence.
Example Output:
1