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: 'the zebra is walking through the tall brown grass'. How many words start with the letter 't' in the sentence.
Example Output: 4

Example Input: Sentence: 'a cow that is standing in the grass'. How many words start with the letter 't' in the sentence.
Example Output: 2

Example Input: Sentence: 'people gather around an outdoor fruit market'. How many words start with the letter 'a' in the sentence.
Example Output:
2