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: 'several people watch cars drive by with bikes on them'. How many words start with the letter 'b' in the sentence.
2

Sentence: 'a man touching a bird on top of a cage'. How many words start with the letter 'a' in the sentence.
3

Sentence: 'a person in a black full body wetsuit riding a surfboard on a wave in the water'. How many words start with the letter 'a' in the sentence.

4