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 on a bike and a banana in the pocket'. How many words start with the letter 'a' in the sentence.
Example Output: 4

Example Input: Sentence: 'a boat floating on a lake next to a shore filled with buildings'. How many words start with the letter 'n' in the sentence.
Example Output: 1

Example Input: Sentence: 'old junked blue truck in a field between two dead trees'. How many words start with the letter 't' in the sentence.
Example Output:
3