问题1480--Interesting Punch-Bowl

1480: Interesting Punch-Bowl

时间限制: 1 Sec  内存限制: 128 MB
提交: 18  解决: 9
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题目描述

Dr.Kong has taken a side job designing interesting punch-bowl designs. The designs are created as follows:
      * A flat board of size W cm *  H cm is procured        (3 <= W <= 300, 3 <= H <= 300)
      * On every 1 cm x 1 cm square of the board, a 1 cm x 1 cm block is placed.  This block has some integer height B     (1 <= B <= 1,000,000,000)

The blocks are all glued together carefully so that punch will not drain  through them. They are glued so well, in fact, that the corner blocks really don't matter!

Dr.Kong can never figure out, however, just how much punch their bowl designs will hold. Presuming the bowl is freestanding (i.e., no special walls around the bowl), calculate how much juice the bowl can hold.  Some juice bowls, of course, leak out all the juice on the edges and will hold 0.

输入

  * Line 1: Two space-separated integers, W and H
* Lines 2..H+1: Line i+1 contains row i of bowl heights: W  space-separated integers each of which represents the height B of a square in the bowl.  The first integer is the height of column 1, the second integers is the height of column 2, and so on.

输出

* Line 1: A single integer that is the number of cc's the described bowl will hold.

样例输入 Copy
4 5 
5 8 7 7
5 2 1 5
7 1 7 1
8 9 6 9
9 8 9 9
样例输出 Copy
12