#include <bits/stdc++.h>

using namespace std;

void fast_io() {
	ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
}

int main() {
	fast_io();
	int h, w;
	cin >> h >> w;
	vector<vector<int>> a(h + 2, vector<int>(w + 2, 0));
	for (int i = 1; i <= h; i++) {
		for (int j = 1; j <= w; j++) {
			cin >> a[i][j];
		}
	}
	vector<pair<int, int>> out;
	for (int i = 0; i <= h + 1; i++) {
		out.push_back({i, 0});
		out.push_back({i, w + 1});
	}
	for (int i = 0; i <= w + 1; i++) {
		out.push_back({0, i});
		out.push_back({h + 1, i});
	}
	int dx[] = {1, 1, 0, -1, -1, -1, 0, 1};
	int dy[] = {0, 1, 1, 1, 0, -1, -1, -1};
	int ans = 0;
	for (auto [i1, j1] : out) {
		for (int d1 = 0; d1 < 8; d1++) {
			int i = i1, j = j1;
			vector<vector<bool>> vis(h + 2, vector<bool>(w + 2, false));
			int score_cur = 0;
			while (true) {
				vis[i][j] = true;
				score_cur += a[i][j];
				i += dx[d1];
				j += dy[d1];
				if (i < 1 || i > h || j < 1 || j > w) {
					break;
				}
			}
			for (auto [i2, j2] : out) {
				for (int d2 = 0; d2 < 8; d2++) {
					int score = score_cur;
					int i = i2, j = j2;
					while (true) {
						if (!vis[i][j]) {
							score += a[i][j];
						}
						i += dx[d2];
						j += dy[d2];
						if (i < 1 || i > h || j < 1 || j > w) {
							break;
						}
					}
					ans = max(ans, score);
				}
			}
		}
	}
	cout << ans << endl;
}