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: Jack collected books about wrestlers. Sentence 2: Jack sold one of these books to the bookstore for six dollars. Sentence 3: Later he learned that the bookstore was selling the book for $50. Sentence 4: After doing some research, Jack discovered he had sold a rare book. Sentence 5: Jack vowed to do more research before selling another book.

Jack's Disappointment