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 woman walks in the street in the rain'. How many words start with the letter 'i' in the sentence.
Example Output: 2

Example Input: Sentence: 'horses are being walked around a race track'. How many words start with the letter 't' in the sentence.
Example Output: 1

Example Input: Sentence: 'a traffic light indicating green for the bicycle lane'. How many words start with the letter 'g' in the sentence.
Example Output:
1