Hi, Codeforces!

Happy New Year! Holidays and 2015 year have passed and year 2016 is ahead. I wish you good luck in programming competitions and achieving all of your goals this year.

Educational Codeforces Round 5 will take place on 11 January 2016 at 18:00 MSK for the first and second divisions. You can read about educational rounds here and here.

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The round will be unrated for all users and it will be held with extented ACM ICPC rules. You will have two hours to solve six problems. After that you will have one day to hack any solution you want. You will have access to copy any solution and test it locally.

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Thanks a lot to Grigory Reznikow vintage_Vlad_Makeev who prepared a good problem (the problem F in ER 5). You can send to me some ideas of problems or maybe already prepared problems that you can't use in rounds or official competitions.

As usual the round was prepared by me, Edvard Davtyan. Thanks a lot to MikeMirzayanov for helping to invent the problems. Also thanks in advance to Maria Belova Delinur who will check English statements.

I think the problems is not difficult (except maybe for problem F). I hope you will enjoy the problems and solve all of them!

Good luck and have fun!

UPD 1: Coding phase is finished. You can hack other solutions for 24 hours.

UPD 2: The editorial is ready.

UPD 3: During the phase of hacks we found the following: the same solutions on Python2 and Python3 works differently on different large tests. For example, some of Python3 solutions works very slow on tests with only zeros, but Python2 works very slow on tests with nines. Some of solutions works in around one second so we decided to increase the time limit for the problem A to 2 seconds. All the solutions will be rejudged soon on the complete testset.