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 standing next to a car talking on the phone'. How many words start with the letter 't' in the sentence.
Example Output: 3

Example Input: Sentence: 'a man wearing glasses collecting samples in a container in a forest'. How many words start with the letter 'g' in the sentence.
Example Output: 1

Example Input: Sentence: 'a couple of zebra standing next to each other'. How many words start with the letter 'n' in the sentence.
Example Output:
1