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: 'the inside of a toilet stall on an airplane'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a pitcher throwing a baseball during a baseball game'. How many words start with the letter 'b' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'a couple of stuffed animals on a bench by a walkway'. How many words start with the letter 'a' in the sentence.

Ex Output:

4