Tired to rest? Your help is needed.
During the period from December 31 until today I have made many changes in the Codeforces. The changes affected only the interior, so you will not notice any change in the user interface. Nevertheless, during this time was changed about 150 project files, database schema, some principles of data storage. In short, after all this, I'm not sure that everything works as expected (although, of course, I spent time on testing). For this reason I decided to organize Codeforces Testing Round #1, which will unrated and his only goal - a comprehensive testing of the project in conditions close to the real contest.
It will be three problems (possibly well-known, folklore), but I hope it will be pleasure to solve them.
Thanks for the help to Artem Rakhov, Maria Belova, and Max Ivanov
UPD: Thanks to all. The round finished. We didn't notice any bugs. Write suggestions and opinions in the comments.