I uploaded 2020 Petrozavodsk Winter Camp, Jagiellonian U Contest to the CF Gym.
In the version used in PtzCamp and NAPC, problem K had a weak test and the model solution failed in my simple handcrafted tests. I just added that test, and changed the problem limit leniently to allow model solution to pass. I guess this made the problem much easier now.
Thanks to the problemsetters (I don't know who are them). Enjoy!