Once, someone asked me if it's legal to use ChatGPT in CF rounds. I suggested him not to use it, because it may hamper his critical thinking. I know that it's illegal to use resources that are lublished after the round starts. But ChatGPT is answering in realtime. Some people want to compare it with searching in Google. Though, I know that ChatGPT just matches pattern with the existing data. Is there any official rule about using ChatGPT in CF roounds? If any, what is it?