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: 'dusty train passing through a dry mountain valley'. How many words start with the letter 'd' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'a rusty metal park bench in a park'. How many words start with the letter 'a' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'a red motorcycle is parked on the street'. How many words start with the letter 'r' in the sentence.

Ex Output:

1