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.

Sentence: 'a man talks on the cellphone outside of a building'. How many words start with the letter 'o' in the sentence.
3

Sentence: 'the men are holding on to surfboards outside'. How many words start with the letter 'o' in the sentence.
2

Sentence: 'a toilet that is next to a bathtub in a bathroom'. How many words start with the letter 'a' in the sentence.

3