Codeforcesβ Sponsored by Telegram (abbr. CF) is a Russian website dedicated to competitive programming. It was created and is maintained by a group of competitive programmers from Saratov State University led by Mikhail Mirzayanov. Every year, CF hosts a lot of competitions like Intel Code Challenge, Russian Code Cup, Codeforces Rounds, etc. It is world-famous because of its challenging problems. A large of Chinese students and hackers also like to solve problems on CF. What's more, the rank system of the competitors is very unique. There are "Red Names"(Legendary Grandmaster /International Grandmaster/Grandmaster)(Legendary Grandmaster has black initial), "Yellow Names"(Master), "Violet Names"(Candidate Master), "Blue Names"(Expert), "Cyan Names"(Specialist), "Green Names"(Pupil) and "Grey Names"(Newbie) according to their rating bounds.