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 yellow grey and white bird on a small group of twigs'. How many words start with the letter 'b' in the sentence.
1

Sentence: 'a person riding a skateboard down a street'. How many words start with the letter 'a' in the sentence.
3

Sentence: 'a tennis player lines up to return the ball'. How many words start with the letter 'u' in the sentence.

1