In this task, you need to count the number of words in a sentence that contain the given letter
Example: Sentence: 'two gray birds standing in a green field'. How many words contain the letter 'a' in the sentence.
Example solution: 3
Example explanation: The words 'gray', 'standing', and 'a' contain the letter 'a'. So, the answer is 3.

Problem: Sentence: 'a room filled with a motorcycle and lots of junk'. How many words contain the letter 's' in the sentence.

Solution: 1