Hello, dear Codeforces community!
I'm glad to present you the next Codeforces Round #121. The contest is brought to you by Ivan Smirnov (ifsmirnov) and Aleksandr Timin (AlTimin), the students of Moscow Institute of Physics and Technology. In our first round we will offer you a good time in Berland: you will hold a demonstration, prevent the demonstration, deal with the most important problems of Berland (with both of them!) and much more.
We thank Gerald a lot for the invaluable help he gave as during the contest preparation. He is also the author of one task in the contest. We also thank Delinur for the English version of statements, Aksenov239 for proofreading the statements and MikeMirzayanov for an opportunity to hold a contest on this wonderful site.
As usual, the contest will be held in both divisions and the problemsets will overlap. The scoring will be published later.
We wish you good luck and hope that you enjoy the contest!
UPD1: The scoring is classic in both divisions — 500-1000-1500-2000-2500.
UPD2: The contest authors apologize to the contesters for a possibility of misunderstanding of problem B div 1 (D div 2). The statement was fixed soon enough and the incorrect understanding of the problem didn't pass pretests, so the round is rated.