In this task, you need to count the number of words in a sentence that contain the given letter

Ex Input:
Sentence: 'a crowd of people flying kites near the capitol building'. How many words contain the letter 'a' in the sentence.

Ex Output:
3

Ex Input:
Sentence: 'two elephants in the water in front of a waterfall'. How many words contain the letter 'x' in the sentence.

Ex Output:
0

Ex Input:
Sentence: 'the empty street has a sign over it'. How many words contain the letter 'y' in the sentence.

Ex Output:
1