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Task :: Guarding the Farm
The farm has many hills upon which Farmer John would like to place guards to ensure the safety of his valuable milk-cows.

He wonders how many guards he will need if he wishes to put one on top of each hill. He has a map supplied as a matrix of integers; the matrix has N (1 < N ≤ 700) rows and M (1 < M < 700) columns. Each member of the matrix is an altitude H_ij (0 ≤ H_ij ≤ 10,000). Help him determine the number of hilltops on the map.

A hilltop is one or more adjacent matrix elements of the same value surrounded exclusively by either the edge of the map or elements with a lower (smaller) altitude. Two different elements are adjacent if the magnitude of difference in their X coordinates is no greater than 1 and the magnitude of differences in their Y coordinates is also no greater than 1.


INPUT:
* Line 1: Two space-separated integers: N and M
* Lines 2..N+1: Line i+1 describes row i of the matrix with M space-separated integers: H_ij


OUTPUT:
* Line 1: A single integer that specifies the number of hilltops


Input:
8 7
4 3 2 2 1 0 1
3 3 3 2 1 0 1
2 2 2 2 1 0 0
2 1 1 1 1 0 0
1 1 0 0 0 1 0
0 0 0 1 1 1 0
0 1 2 2 1 1 0
0 1 1 1 2 1 0

Output:
3

Hint:
There are three peaks: The one with height 4 on the left top, one of the points with height 2 at the bottom part, and one of the points with height 1 on the right top corner.
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Task info
Name:Guarding the Farm
Time:1 sec.
Memory:32 MB
#Tests:15
AddedBy: Gorgi...
Source:Elite 2008 November Competition USACO
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Difficulty:

3.5 (6 votes)
Quality:

4.2 (5 votes)
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