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 bus is parked on the side of a road in front of a building'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'there is a chocolate muffin on the plate'. How many words start with the letter 'i' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'an old picture of a couple sitting on a bench together with the sea in the background'. How many words start with the letter 'a' in the sentence.

Ex Output:

3