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: I wrote a long letter to my friend Ryan. Sentence 2: I put the letter in the mailbox. Sentence 3: I waited several weeks to receive a reply. Sentence 4: The letter I sent was returned to me. Sentence 5: I still don't know what happened to Ryan.

Letter to Ryan