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 man and boy blow out a candle on a birthday cake'. How many words start with the letter 'a' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a couple of people flying a kite in a field'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'an urban street contains buildings and an electric street car on one side of the road and many parked bicycles on the other'. How many words start with the letter 's' in the sentence.

Ex Output:

3