Chen Xu's computer was lost, so he came up with an idea. He took a thick piece of paper and wrote the following paragraph with black ink that wouldn't fade easily: "My descendants, I am your ancestor Chen Xu. The time now is September 1, 2006, Beijing time, 12:07 PM. Today, your ancestor encountered the most miserable event of his life... On the first day of my university, my laptop worth eight thousand yuan was stolen. If you are my descendants, please help your ancestor with something. If the legendary time machine has appeared in your era, then please send a laptop to the time period I am in now. The address is Room 207, Building 14, HeXie University, XX Province, XX City." One minute later, a computer from the future descended from the sky...