I think ABC is the normal. I don`t no why people hate B, this is not hard mathematical problem. D is very random. AC for proof for me and i think for many peoples. Round is the normal, but i was very stupid on D (+5).
I think ABC is the normal. I don`t no why people hate B, this is not hard mathematical problem. D is very random. AC for proof for me and i think for many peoples. Round is the normal, but i was very stupid on D (+5).