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 Input:
Sentence: 'people on a tour bus with half the top cut off'. How many words start with the letter 'b' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'a photo of a waterway with several boats along the shore'. How many words start with the letter 'w' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'an older man and woman riding on a motorcycle'. How many words start with the letter 'a' in the sentence.

Ex Output:

3


