. . 20. . . . . . naver . [] 1 2.

3 . . . naver . . . . ng. . ! . .

. . . . . . naver . . . . . . . //ng. .

. 2. [] 1. . . . 50 solve it. . . . . .

. [] 1. . . 20. . . . 7. . . . naver . 20170720.

ng. 3 . . . . 1. . 2. [] 1. . . naver . 20170720. . .

naver . [] 1 2.