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__    __     ___      _____     _____     ______  
\ \\ / //   / _ \\   /  ___||  |  ___||  /_   _// 
 \ \/ //   / //\ \\ | // __    | ||__      | ||   
  \  //   |  ___  ||| \\_\ ||  | ||__     _| ||   
   \//    |_||  |_|| \____//   |_____||  /__//    
    `     `-`   `-`   `---`    `-----`   `--`

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發送短信 : Random assignments on preference domains with a tier structure