Today is coming regular Codeforces round #161 for Div.2 participants. Traditionally the others can take part out of the competition.
The problems were prepared by authors: Pavel Kholkin (HolkinPV), Nikolay Kuznetsov (NALP) and Gerald Agapov (Gerald). Traditionally thanks to Michael Mirzayanov (MikeMirzayanov) for Codeforces system and Mary Belova (Delinur) for translating the problems. Also thanks to Rakhov Artem (RAD) and Vitaly Aksenov (Aksenov239) for their help.
UPD: Today it is decided to use dynamic scoring system. But the problems will be sorted from low difficulty to high by authors' opinion!
We wish everyone good luck, successful hacks and high rating!
UPD2: the contest is over) hope you enoy it
Congratulations to winners:
UPD3: the tutorial is published, you can find it here