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

Example Input: Sentence: 'a teddy bear that is sitting up on the ground'. How many words contain the letter 'm' in the sentence.
Example Output: 0

Example Input: Sentence: 'a clothing line with teddy bears hung by their ears'. How many words contain the letter 'n' in the sentence.
Example Output: 3

Example Input: Sentence: 'a snow covered street sign hanging from the side of a pole'. How many words contain the letter 'a' in the sentence.
Example Output:
3