Hello, Codeforces!

We are happy to invite you to the VI UnBalloon Contest Mirror on May/18/2025 20:00 (Moscow time) . UnBalloon is the competitive programming community of University of Brasília.

This contest is a Codeforces Gym, and therefore is NOT an official Codeforces Round and is NOT rated.. The contest will follow standard ICPC rules.

All problems were created and prepared by me, duduFreire, lucassala, PedroGallo, MagePetrus and wallacelw.

Also, we would like to thank:

• Our problem reviewers/testers: cebolinha, EYZ, isasouza and Vilsu;
• Professors dporto and viniciusrpb for the support on the on-site contest and all UnBalloon activities;
• DOM Judge team for the platform used in the on-site contest;
• dario2994 for the brilliant pol2dom tool;
• MikeMirzayanov for the amazing Codeforces and Polygon platforms.

Most of the problems are targeted to those who are starting their journey in competitive programming. However, we also included a few problems we believed will be an interesting challenge for more experienced participants, such as finalists of ICPC Regionals. We hope the contest to be balanced enough to have all kinds of teams thinking on challenging tasks until the end!

Good luck to all participants!

Note: if you participated in the on-site contest, please don't make any kind of comment regarding the problems in this blog. As soon as the Mirror finishes, we will publish an editorial — you may discuss the problems there.