Thanks for the answers — super informative!

1. This series of rounds is held for the first time, so there might be not much participants. Thus, in the first series, we plan not to set any restrictions for semifinals and finals. Everyone is encouraged to register.

It kind of makes sense but from the other hand setting up some advancement rules will justify existence of the Advanced rounds and force more people to participate in them vs just going for Semifinals/Finals. For comparison — see participants number of MHC 2022 Qualification Round (27k people) where you needed to solve 1 problem in order to qualify for the main rounds vs next year's optional MHC 2023 Practice Round (just 12k) hosted in a similar format and designed to replace mandatory qualification. I understand that downside of setting such a rule can decrease pool of participants for Semifinals/Finals in the way you want to avoid (e.g. if somebody strong enough to pass will simply miss it). But otherwise I believe that you'll miss much more people on those 2 optional rounds which you are also clearly putting efforts into.

THANKS! WILL TRY!