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 car sitting on a train carriage on the tracks'. How many words start with the letter 'a' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'a picture of a very clean bed in the room'. How many words start with the letter 'r' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'a clutter area with a books on a shelf'. How many words start with the letter 'a' in the sentence.

Ex Output:

4