I saw that there are ODT and Ynoi in the problem makers. That will remind me and you (especially some old CF users) of CF #896.

These two men are genious Chinese data-structure makers, I'm convienced that this round will be a poisonous and difficult data-structure round. It's so possible (very very high rate) that there will be Mos-algorithm or Sqrt-tech-data-structures.

Please Forgive my broken English and wish you all have a high rating and a happy codeforces round ！