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 person doing a trick in the water'. How many words start with the letter 'i' in the sentence.
Example Output: 1

Example Input: Sentence: 'a group of people sitting at a long table in  a wine cellar'. How many words start with the letter 'a' in the sentence.
Example Output: 4

Example Input: Sentence: 'a very small bathroom with only a toilet inside'. How many words start with the letter 'a' in the sentence.
Example Output:
2