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 white glass vase filled with flowers on top of a table'. How many words start with the letter 'o' in the sentence.
2

Sentence: 'the bearded man is posing in a suit'. How many words start with the letter 'a' in the sentence.
1

Sentence: 'a red fire hydrant in front of a sign reading sidewalk closed'. How many words start with the letter 'r' in the sentence.

2