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

Input: Consider Input: Sentence: 'a clock tower next to a building in a city'. How many words contain the letter 'a' in the sentence.

Output: 3

Input: Consider Input: Sentence: 'a girl at a lake is looking at sand inside of a frisbee'. How many words contain the letter 'u' in the sentence.

Output: 0

Input: Consider Input: Sentence: 'a couple of people sitting down in a street'. How many words contain the letter 'o' in the sentence.
Output: 4