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 person on a snowboard on a snowy day'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a person sitting on a stone wall using a cellular phone'. How many words start with the letter 's' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'a person sitting on a stone wall using a cellular phone'. How many words start with the letter 's' in the sentence.

Ex Output:

2