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 man in vest and tie holding a cellphone'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a couple of people are riding horses in a village'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a young man flying through the air while riding a surfboard'. How many words start with the letter 'y' in the sentence.

Ex Output:

1