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

Input: Consider Input: Sentence: 'a little girl sitting on the floor reading a book'. How many words contain the letter 'n' in the sentence.

Output: 3

Input: Consider Input: Sentence: 'a man flying through the air while riding a snowboard'. How many words contain the letter 'x' in the sentence.

Output: 0

Input: Consider Input: Sentence: 'a bunch of people is watching something and a man in a brown and blue stripped shirt has his fingers in his ears'. How many words contain the letter 'r' in the sentence.
Output: 5