Competition Number: For 20th competition and beyond. 只对二十期及以后的比赛有效。
Extra Level [副关]:
Extra Level 2 [副关2]:
Extra Level 3 [副关3]:
Check this box for the extra level. 默认为主关，副关请把此选项勾上。且只能勾选一个。
Name(ID): Please use only letters (a...z, A...Z) and numbers (0...9) in your ID,
and make sure there are no leading or trailing spaces.
Solution: (Paste in only the LURD solution, no extra text. Submit only one solution at a time.)