#include <bits/stdc++.h>

#define el '\n'
#define ll long long
#define ld long double

#define Beevo ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

using namespace std;

int h, w;
int dx[] = {0, 0, -1, 1};
int dy[] = {-1, 1, 0, 0};

bool valid(int x, int y) {
    return x >= 0 && x < h && y >= 0 && y < w;
}

void testCase() {
    cin >> h >> w;

    int g[h][w];
    vector<pair<int, int>> lvl[h * w];
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            cin >> g[i][j];

            if (g[i][j] > 1)
                lvl[g[i][j]].emplace_back(i, j);
        }
    }

    bool b[h][w];
    memset(b, 0, sizeof b);

    int sol = 0;
    for (int i = h * w - 1; i >= 2; i--) {
        priority_queue<pair<int, pair<int, int>>> pq;

        for (auto j: lvl[i]) {
            int x = j.first, y = j.second;

            pq.push({b[x][y], {x, y}});

            for (int k = 0; k < 4; k++) {
                int newX = x + dx[k], newY = y + dy[k];

                if (valid(newX, newY) && g[newX][newY] < i)
                    b[newX][newY] = 1;
            }
        }

        while (pq.size()) {
            int x = pq.top().second.first;
            int y = pq.top().second.second;

            pq.pop();

            if (!b[x][y])
                sol++, b[x][y] = 1;

            for (int k = 0; k < 4; k++) {
                int newX = x + dx[k], newY = y + dy[k];

                if (valid(newX, newY) && g[newX][newY] == i && !b[newX][newY]) {
                    b[newX][newY] = 1;

                    pq.push({1, {newX, newY}});
                }
            }
        }
    }

    cout << sol;
}

signed main() {
    Beevo

    int T = 1;
//    cin >> T;

    while (T--)
        testCase();

    return 0;
}