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: Billy's basketball went flat. Sentence 2: He was very disappointed. Sentence 3: He decided to buy a new one. Sentence 4: He saved up money to buy it. Sentence 5: He went and bought a new one.

Basketball.