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 boy standing on sand and flying a green kite'. How many words start with the letter 'f' in the sentence.

Ex Output:
1

Ex Input:
Sentence: 'a man pitching a baseball from a mound to a home plate'. How many words start with the letter 'a' in the sentence.

Ex Output:
4

Ex Input:
Sentence: 'a group of children sitting at a table ready to order food'. How many words start with the letter 'g' in the sentence.

Ex Output:
1