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

Example Input: Sentence: 'the zebra is showing his rear end to the camera'. How many words contain the letter 'r' in the sentence.
Example Output: 3

Example Input: Sentence: 'a little girl sitting on the floor reading a book'. How many words contain the letter 'n' in the sentence.
Example Output: 3

Example Input: Sentence: 'a cute gry cat walking trough a cat door onto a hard wood floor'. How many words contain the letter 'f' in the sentence.
Example Output:
1