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 msall bus going down a road with a street sign'. How many words start with the letter 'd' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'kids at a skateboard park riding skateboards and watching'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a yellow boat sitting on a beach surrounded by snow covered mountains'. How many words start with the letter 'b' in the sentence.

Ex Output:

3