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

Input: Consider Input: Sentence: 'a jet airliner carrying a small shuttle above it'. How many words contain the letter 'r' in the sentence.

Output: 2

Input: Consider Input: Sentence: 'a group of many horses going about in a grassy meadow'. How many words contain the letter 'f' in the sentence.

Output: 1

Input: Consider Input: Sentence: 'a onecart train coming down the railroad tracks'. How many words contain the letter 'k' in the sentence.
Output: 1