Hi to all!
A few hours later you're lucky to participate in Codeforces Round #149 for Div.2 participants, but traditionally the others can take part out of the competition. It has been prepared by me (NALP), Igor Kudryashov (KudryashovIA), Pavel Holkin (HolkinPV) and Gerald Agapov (Gerald). Also we express thanks to Mary Belova (Delinur) and Mike Mirzayanov (MikeMirzayanov).
Traditionally I wish good luck, accepted solutions and successful hacking attempts for you!
The standart scoring system will be used: 500-1000-1500-2000-2500
UPD: The contest is over, thanks to all!
UPD: Congratulations to the winners:
UPD: the tutorial has been published.