Solved by rubytest

#	Title	# Solved	Avg. Tries
1000	A+B STANDARD	306,183	2.57
1001	A-B STANDARD	262,582	1.44
1008	A/B STANDARD	215,716	2.90
2557	Hello World STANDARD	338,882	2.54
10998	A×B STANDARD	218,081	1.30
16904	집합과 쿼리	38	2.00

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