#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } else { return false; } }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } else { return false; } }
#define rep(i, s, n) for(int i = (s); i < n; i++) 
#define reps(i, s, n) for(int i = (s); i <= n; i++) 
#define rrep(i, n, s) for(int i = n; i >= (s); i--)
#define all(x) (x).begin(), (x).end()
#define print(V) for (int z = 0; z < (V).size(); z++) { cout << V[z] << " "; } cout << endl;
#define MOD 998244353
#define MOD2 1000000007
#define INF 1LL << 60
#define PI acos(-1)

int h, w;
vector< vector<int> > A;
vector< vector<bool> > seen;
vector< vector<int> > vec;

int vx[8] = { -1, -1, 0, 1, 1, 1, 0, -1 };
int vy[8] = { 0, -1, -1, -1, 0, 1, 1, 1 };

ll calc(int x, int y, int s, bool flag) {
	ll res = 0;

	while (1) {
		x += vx[s];
		y += vy[s];

		if (x < 0 || x >= h + 2) {
			break;
		}
		if (y < 0 || y >= w + 2) {
			break;
		}
		if (!seen[x][y]) {
			res += A[x][y];
			if (flag) {
				seen[x][y] = true;
			}
		}
	}

	return res;
}

ll solve(vector<int> d1, vector<int> d2) {
	ll res = 0;
	ll d1_calc = 0, d2_calc = 0;

	rep(i, 0, 8) {
		seen.assign(h + 2, vector<bool>(w + 2, false));
		d1_calc = calc(d1[0], d1[1], i, true);

		rep(j, 0, 8) {
			d2_calc = calc(d2[0], d2[1], j, false);

			chmax(res, d1_calc + d2_calc);
		}
	}

	return res;
}

int main(void) {
	cin >> h >> w;

	A.assign(h + 2, vector<int>(w + 2));
	rep(i, 1, h + 1) {
		rep(j, 1, w + 1) {
			cin >> A[i][j];
		}
	}

	vector<int> p(2);  //[0]: x座標, [1]: y座標
	rep(i, 0, h + 2) {
		if (i == 0 || i == h + 1) {
			rep(j, 0, w + 2) {
				p[0] = i;
				p[1] = j;
				vec.push_back(p);
			}
		}
		else {
			for (int j = 0; j < w + 2; j += (w + 1)) {
				p[0] = i;
				p[1] = j;
				vec.push_back(p);
			}
		}
	}

	//rep(i, 0, vec.size()) {
	//	print(vec[i]);
	//}

	seen.assign(h + 2, vector<bool>(w + 2, false));
	int vs = vec.size();
	ll ans = 0;

	rep(i, 0, vs) {
		rep(j, 0, vs) {
			if (i == j) {
				continue;
			}

			chmax(ans, solve(vec[i], vec[j]));
		}
	}

	cout << ans << endl;

	return 0;
}