Statements may vary slightly from the final, distributed directly on the competition. For example, just at the contest I saw on paper phrase "zoom ration" (???), though in the older (this) version it was "zoom ratio", as it should be.

I'm interested in feedback on these tasks, because I prepared them (of course, special thanks to Ukrainian methodical commission who helped me much).

Particulary, I'm very interested that the problem G was solved, and it is rumored that a significant part of solutions principally differs from my solution. Vasyl[Alphacom] (Vasyl Biletsky) told me few words about how to use RMQ here; but, alas, yesterday I realized that misunderstood him :(