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 group of people that are by and elephant'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a person standing on a green field next to a river flying a kite'. How many words start with the letter 'a' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a group of hipster friends posing for a picture together'. How many words start with the letter 'a' in the sentence.

Ex Output:

2