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 computer with a farm on the screen on top of a desk'. How many words start with the letter 'o' in the sentence.
Example Output: 3

Example Input: Sentence: 'a train moves across a train crossing in a city'. How many words start with the letter 'c' in the sentence.
Example Output: 2

Example Input: Sentence: 'a woman plays frisbee with her dog in the snow'. How many words start with the letter 't' in the sentence.
Example Output:
1