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: 'a counter topped with vases in front of a window'. How many words start with the letter 'w' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'a man riding on top of a wave on a surfboard'. How many words start with the letter 'o' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'boy skateboarding indoors on a platform surround a tree'. How many words start with the letter 's' in the sentence.

Ex Output:

2