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


[Q]: Sentence: 'two men on motorcycles and wearing helmets'. How many words start with the letter 'w' in the sentence.
[A]: 1


[Q]: Sentence: 'zebras and antelopes in a field of dried grass'. How many words start with the letter 'a' in the sentence.
[A]:
3