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 close up of a baby with a tooth brush'. How many words start with the letter 'a' in the sentence.

A: 3
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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
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Q: Sentence: 'a yellow biplane flying under a blue sky'. How many words start with the letter 'b' in the sentence.

A:
2
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