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.

[EX Q]: Sentence: 'some black birds sitting on some rocks and some water'. How many words start with the letter 'b' in the sentence.
[EX A]: 2

[EX Q]: Sentence: 'a man is carrying a large case with him'. How many words start with the letter 'w' in the sentence.
[EX A]: 1

[EX Q]: Sentence: 'someone in a building is walking and carrying a skateboard'. How many words start with the letter 'a' in the sentence.
[EX A]:
3