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.

[Q]: Sentence: 'the inside of a toilet stall on an airplane'. How many words start with the letter 'a' in the sentence.
[A]: 3


[Q]: Sentence: 'a terrier in a black and light brown far next to each other'. How many words start with the letter 'b' in the sentence.
[A]: 2


[Q]: Sentence: 'a man riding on top of a wave on a surfboard'. How many words start with the letter 'o' in the sentence.
[A]:
3