#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; i--)
#define rrep1(i, n) for (int i = n; i >= 1; i--)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define eb emplace_back
#define fi first
#define se second
#define sz(x) (int)(x).size()
template <class T> using V = vector<T>;
template <class T> using VV = V<V<T>>;
typedef long long int ll;

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

template <class T> bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template <class T> bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
/*--------------------------------------------------*/
typedef pair<int, int> P;

const int INF = 1e9;
const ll LINF = 1e18;
const int MAX = 100010;

void solve() {
    int h, w;
    cin >> h >> w;
    VV<int> a(h, V<int>(w));
    rep(i, h) rep(j, w) cin >> a[i][j];
    int ans = 0;
    auto upd = [&](set<P> p, set<P> &p2) -> void {
        for (auto [pi, pj] : p2) p.insert({pi, pj});
        int sum = 0;
        for (auto [pi, pj] : p) sum += a[pi][pj];
        chmax(ans, sum);
    };
    auto f = [&](set<P> &p) -> void {
        rep(i2, h) {
            auto p2 = set<P>();
            rep(j2, w) p2.insert({i2, j2});
            upd(p, p2);
        }
        rep(j2, w) {
            auto p2 = set<P>();
            rep(i2, h) p2.insert({i2, j2});
            upd(p, p2);
        }
        rep(i2, h) {
            auto p2 = set<P>();
            rep(j2, w) {
                if (i2 + j2 >= h) break;
                if (j2 >= w) break;
                p2.insert({i2 + j2, j2});
            }
            upd(p, p2);
        }
        rep(j2, w) {
            auto p2 = set<P>();
            rep(j2d, w) {
                if (j2d >= h) break;
                if (j2 + j2d >= w) break;
                p2.insert({j2d, j2 + j2d});
            }
            upd(p, p2);
        }
        rep(i2, h) {
            auto p2 = set<P>();
            rep(j2, w) {
                if (i2 - j2 < 0) break;
                if (j2 >= w) break;
                p2.insert({i2 - j2, j2});
            }
            upd(p, p2);
        }
        rep(j2, w) {
            auto p2 = set<P>();
            rep(j2d, w) {
                if (j2d >= h) break;
                if (j2 - j2d < 0) break;
                p2.insert({j2d, j2 - j2d});
            }
            upd(p, p2);
        }
    };
    rep(i, h) {
        set<P> p;
        rep(j, w) p.insert({i, j});
        f(p);
    }
    rep(j, w) {
        set<P> p;
        rep(i, h) p.insert({i, j});
        f(p);
    }
    rep(i, h) {
        set<P> p;
        rep(j, w) {
            if (i + j >= h) break;
            p.insert({i + j, j});
        }
        f(p);
    }
    rep(j, w) {
        set<P> p;
        rep(jd, w) {
            if (jd >= h) break;
            if (j + jd >= w) break;
            p.insert({jd, j + jd});
        }
        f(p);
    }
    rep(i, h) {
        set<P> p;
        rep(j, w) {
            if (i - j < 0) break;
            p.insert({i - j, j});
        }
        f(p);
    }
    rep(j, w) {
        set<P> p;
        rep(jd, w) {
            if (jd >= h) break;
            if (j - jd < 0) break;
            p.insert({jd, j - jd});
        }
        f(p);
    }
    cout << ans << "\n";
}

int main() {
    speedUpIO();
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
        // cout << solve() << "\n";
        // cout << (solve() ? "Yes" : "No") << "\n";
        // cout << fixed << setprecision(15) << solve() << "\n";
    }
    return 0;
}