Definition: In this task, you're given five sentences, numbered 1 through 5. Your job is to generate a title for the story that makes complete sense. The title must be short, with less than three words, use simple language, and include the main topic of the story.
Input: Sentence 1: Greg cracked his knuckles. Sentence 2: That sound gave his wife the creeps. Sentence 3: The wife asked him to stop. Sentence 4: The man cracked his knuckles more. Sentence 5: The wife felt physically ill.

knuckles