번호	제목
18720	Bookface
18721	Clique
18722	Contamination
18723	The Halfwitters
18724	Invited Speakers
18725	Lighthouses
18726	Sum of Palindromes
18727	Space Gophers
18728	To argue, or not to argue
18729	Wizards Unite
18730	Outlier
18731	A Math Problem
18732	A Permutation Problem
18733	Split in Sets
18734	The Destruction of the Crystals
18735	Balls
18736	Football Match
18737	Hill
18738	Special Game
18739	Even More Exciting Game