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: 'some signs buildings trees bushes a green and white sign'. How many words start with the letter 's' in the sentence.
[A]: 3


[Q]: Sentence: 'a small airplane sitting on top of a runway'. How many words start with the letter 'a' in the sentence.
[A]: 3


[Q]: Sentence: 'red and yellow trains sitting side by side to each other'. How many words start with the letter 's' in the sentence.
[A]:
3