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

Example Input: Sentence: 'a couple of zebras are standing in a pin'. How many words contain the letter 'a' in the sentence.
Example Output: 5

Example Input: Sentence: 'a silver truck a street a person and buildings'. How many words contain the letter 'l' in the sentence.
Example Output: 2

Example Input: Sentence: 'a couple of people with umbrellas on a street'. How many words contain the letter 'u' in the sentence.
Example Output:
2