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

Now, solve this: Sentence: 'several containers of food sitting on a table beside a blue mug'. How many words contain the letter 's' in the sentence.
Solution:
4