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: 'some black birds sitting on some rocks and some water'. How many words start with the letter 'b' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'the zebra is walking through the tall brown grass'. How many words start with the letter 't' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a group of men standing on a street corner next to a stop sign'. How many words start with the letter 's' in the sentence.

Ex Output:

4