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 bus and a truck are pictured driving on a street'. How many words start with the letter 'a' in the sentence.

Ex Output:
5


Ex Input:
Sentence: 'two people playing frisbee on the beach on a sunny day'. How many words start with the letter 't' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'five street signs are stacked on a pole in a downtown city'. How many words start with the letter 's' in the sentence.

Ex Output:

3