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

Ex Input:
Sentence: 'a mother zebra standing next to a baby zebra'. How many words contain the letter 'e' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a dog jumping up and catching a frisbee in its mouth'. How many words contain the letter 'r' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'a man holds a horse while others watch'. How many words contain the letter 'r' in the sentence.

Ex Output:

2