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

Ex Input:
Sentence: 'young girls with backpacks are standing near stairs that look to go to the subway'. How many words contain the letter 'r' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a man that is sitting on a horse in the grass'. How many words contain the letter 'y' in the sentence.

Ex Output:
0


Ex Input:
Sentence: 'a dog and cat laying on a couch together'. How many words contain the letter 'a' in the sentence.

Ex Output:

5