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: 'a brown teddy bear is sitting on plaid sheets'. How many words start with the letter 'p' in the sentence.
[EX A]: 1

[EX Q]: Sentence: 'a group of young people riding snow boards down a snow covered hillside'. How many words start with the letter 'a' in the sentence.
[EX A]: 2

[EX Q]: Sentence: 'three traffic signs arranged on a sign post'. How many words start with the letter 's' in the sentence.
[EX A]:
2