九 03
原题：http://www.puzzleup.com/2010/puzzle/?225
We have a number. All the digits of this number are different from one another and all the digits except the first and the last have a greater value than the mean of its neighbors (ie. the digits immediately to the left and to the right).
What can this number be at maximum?
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注：关于puzzleup竞赛，参见这里
