번호	제목
19001	Rikka with XOR
19002	Rikka with Tree Game
19003	Rikka with Equation
19004	Rikka with Lines
19005	Rikka with Bridges
19006	Rikka with Mutex
19007	Rikka with Mirror
19008	Rikka with String
19009	Equal Digits
19010	Remove the Tree
19011	Unseen Segments
19012	Road Connectivity
19013	Binary String
19014	Fair Competition
19015	Token and Dice
19016	Convex Region
19017	Automorphism
19018	Border
19019	Convolution
19020	Decomposition