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 mother bear and her two young are crossing a shallow river'. How many words start with the letter 'a' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a man holding a baby two women and two cakes'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a man with a gray hat balances on his stomach on a piece of luggage in the snow'. How many words start with the letter 'o' in the sentence.

Ex Output:

3