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: When I was younger, I had pen pals all over the world. Sentence 2: I made many friends I never saw in person. Sentence 3: But it was fun to receive letters every week. Sentence 4: All these years later, I remember many of them. Sentence 5: And I think about them on their birthdays.

Pen pals