Hi, Codeforces!

Educational Codeforces Round #1 will take place on 13 ноября 2015 года в 18:00 MSK for the first and second divisions. You can read about educational rounds here.

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 five 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.

Educational rounds are (and would) be prepared by me, Edvard Davtyan from Saratov SU Daemons team. Problems was invented by me and MikeMirzayanov. Thanks to my teammate danilka.pro for testing problems and MikeMirzayanov for Codeforces, Polygon and idea of the educational rounds.

I hope you will enjoy the problems. If they will be too simple for you, you are welcome to the second educational round, problems there should be harder.

Good luck and have fun!

UPD: The first phase of round is over. I remind that the results is not final and you can hack any solution during the day.

UPD2: Please use only deterministic generators. For example you should not use srand(time(NULL)) with calling rand() function in C++. Your generator should always generate the same test.