Guys please... please hire someone to translate your texts from Russian to English... Google Translate can do a better job than some of the people writing contest editorials in English. And the problem statements... it's not that uncommon to spend half the contest time just reading statements over and over again trying to guess what the author meant by saying something that doesn't make sense.

Usually, the problems on CodeForces are quite difficult and fun. By writing in bad English you are removing the fun part.

Please work on this :(

is no good... :)