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

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發送短信 : On an open problem of Kyung Soo Kim