CF442C.Artem and Array

普及/提高-

通过率:0%

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题目描述

Artem has an array of nn positive integers. Artem decided to play with it. The game consists of nn moves. Each move goes like this. Artem chooses some element of the array and removes it. For that, he gets min(a,b)min(a,b) points, where aa and bb are numbers that were adjacent with the removed number. If the number doesn't have an adjacent number to the left or right, Artem doesn't get any points.

After the element is removed, the two parts of the array glue together resulting in the new array that Artem continues playing with. Borya wondered what maximum total number of points Artem can get as he plays this game.

输入格式

The first line contains a single integer nn (1<=n<=5105)(1<=n<=5·10^{5}) — the number of elements in the array. The next line contains nn integers aia_{i} (1<=ai<=106)(1<=a_{i}<=10^{6}) — the values of the array elements.

输出格式

In a single line print a single integer — the maximum number of points Artem can get.

输入输出样例

  • 输入#1

    5
    3 1 5 2 6
    

    输出#1

    11
    
  • 输入#2

    5
    1 2 3 4 5
    

    输出#2

    6
    
  • 输入#3

    5
    1 100 101 100 1
    

    输出#3

    102
    
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