CF140C.New Year Snowmen

普及/提高-

通过率:0%

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题目描述

As meticulous Gerald sets the table and caring Alexander sends the postcards, Sergey makes snowmen. Each showman should consist of three snowballs: a big one, a medium one and a small one. Sergey's twins help him: they've already made nn snowballs with radii equal to r1r_{1} , r2r_{2} , ..., rnr_{n} . To make a snowman, one needs any three snowballs whose radii are pairwise different. For example, the balls with radii 11 , 22 and 33 can be used to make a snowman but 22 , 22 , 33 or 22 , 22 , 22 cannot. Help Sergey and his twins to determine what maximum number of snowmen they can make from those snowballs.

输入格式

The first line contains integer nn ( 1<=n<=1051<=n<=10^{5} ) — the number of snowballs. The next line contains nn integers — the balls' radii r1r_{1} , r2r_{2} , ..., rnr_{n} ( 1<=ri<=1091<=r_{i}<=10^{9} ). The balls' radii can coincide.

输出格式

Print on the first line a single number kk — the maximum number of the snowmen. Next kk lines should contain the snowmen's descriptions. The description of each snowman should consist of three space-separated numbers — the big ball's radius, the medium ball's radius and the small ball's radius. It is allowed to print the snowmen in any order. If there are several solutions, print any of them.

输入输出样例

  • 输入#1

    7
    1 2 3 4 5 6 7
    

    输出#1

    2
    3 2 1
    6 5 4
    
  • 输入#2

    3
    2 2 3
    

    输出#2

    0
    
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