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 brown and white cat laying on blanket on door of open oven'. How many words start with the letter 'o' in the sentence.
Example Output: 5

Example Input: Sentence: 'a woman is standing in the kitchen using her phone'. How many words start with the letter 'w' in the sentence.
Example Output: 1

Example Input: Sentence: 'a train stopped at a train station where people are waiting'. How many words start with the letter 't' in the sentence.
Example Output:
2