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  ______    _____     _  __     ___      ______  
 /_   _//  |  ___||  | |/ //   / _ \\   /_   _// 
   | ||    | ||__    | ' //   / //\ \\    | ||   
  _| ||    | ||__    | . \\  |  ___  ||  _| ||   
 /__//     |_____||  |_|\_\\ |_||  |_|| /__//    
 `--`      `-----`   `-` --` `-`   `-`  `--`

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發送短信 : Colorings of Hyperbolic Plane Crystallographic Patterns