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: 'there is a bird standing on a rocky shore'. How many words start with the letter 'a' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'a black and white photo of a man in the street feeding cats and dogs'. How many words start with the letter 'a' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a group of young skiers standing beneath a ski lift'. How many words start with the letter 's' in the sentence.

Ex Output:

3