#include <algorithm>
#include <iostream>
#include <iomanip>
#include <limits.h>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
#include <stack>
#include <complex>

using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rep1(i, n) for (int i = 1; i < n + 1; i++)
#define rev(i, n) for (int i = n - 1; i >= 0; i--)
#define all(A) A.begin(), A.end()
#define itr(A, l, r) A.begin() + l, A.begin() + r
#define debug(var) cout << #var << " = " << var << endl;
typedef long long ll;

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p)
{
    os << "(" << p.first << "," << p.second << ")";
    return os;
}

template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p)
{
    is >> p.first >> p.second;
    return is;
}

template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v)
{
    for (int i = 0; i < (int)v.size(); i++)
    {
        os << v[i] << (i + 1 != (int)v.size() ? " " : "");
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, const vector<vector<T>> &v)
{
    for (int i = 0; i < (int)v.size(); i++)
    {
        os << v[i] << endl;
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, const vector<vector<vector<T>>> &v)
{
    int n = v.size();
    int m = v[0].size();
    int p = v[0][0].size();
    rep(k, p)
    {
        os << "k = " << k << endl;
        rep(i, n)
        {
            rep(j, m)
            {
                os << v[i][j][k];
                if (j < m - 1)
                {
                    os << " ";
                }
                else
                {
                    os << endl;
                }
            }
        }
    }
    return os;
}

template <typename T>
istream &operator>>(istream &is, vector<T> &v)
{
    for (T &in : v)
        is >> in;
    return is;
}

template <typename T, typename S>
ostream &operator<<(ostream &os, map<T, S> &mp)
{
    for (auto &[key, val] : mp)
    {
        os << key << ":" << val << " ";
    }
    cout << endl;
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, set<T> st)
{
    auto itr = st.begin();
    for (int i = 0; i < (int)st.size(); i++)
    {
        os << *itr << (i + 1 != (int)st.size() ? " " : "");
        itr++;
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, multiset<T> st)
{
    auto itr = st.begin();
    for (int i = 0; i < (int)st.size(); i++)
    {
        os << *itr << (i + 1 != (int)st.size() ? " " : "");
        itr++;
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, queue<T> q)
{
    while (q.size())
    {
        os << q.front() << " ";
        q.pop();
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, deque<T> q)
{
    while (q.size())
    {
        os << q.front() << " ";
        q.pop_front();
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, stack<T> st)
{
    while (st.size())
    {
        os << st.top() << " ";
        st.pop();
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, priority_queue<T> pq)
{
    while (pq.size())
    {
        os << pq.top() << " ";
        pq.pop();
    }
    return os;
}

template <typename T>
ostream &operator<<(ostream &os, priority_queue<T, vector<T>, greater<T>> mpq)
{
    while (mpq.size())
    {
        os << mpq.top() << " ";
        mpq.pop();
    }
    return os;
}
vector<vector<int>> maze;
vector<int> way;
vector<map<int, int>> sum(4);
map<int, pair<int, int>> lim;
vector<int> lefts;
vector<int> rights;
int ans = -2e9;
int h, w;
void dfs()
{
    if (way.size() == 2)
    {
        int p = way[0];
        int q = way[1];
        // debug(vector<int>({p, q}));
        auto [p_min, p_max] = lim[p];
        auto [q_min, q_max] = lim[q];
        for (int i = p_min; i < p_max; i++)
        {
            for (int j = q_min; j < q_max; j++)
            {
                if (p == q && i == j)
                {
                    continue;
                }
                int tmp = sum[p][i] + sum[q][j];
                int a, b, c, d;
                a = lefts[p];
                b = rights[p];
                c = lefts[q];
                d = rights[q];
                // debug(vector<int>({i, j}));
                // debug(vector<int>({a, b, c, d}));
                // debug(tmp);
                int disc = a * d - b * c;
                // debug(disc);
                if (disc)
                {
                    int u = (i * d - j * b) / disc;
                    int v = (-i * c + j * a) / disc;
                    // debug(vector<int>({u, v}));
                    if (0 <= u && u < h)
                    {
                        if (0 <= v && v < w)
                        {
                            tmp -= maze[u][v];
                        }
                    }
                }
                // debug(tmp);
                auto chmax = [](auto &a, auto b)
                { a = max(a, b); };
                chmax(ans,tmp);
            }
        }
        return;
    }
    rep(i, 4)
    {
        way.push_back(i);
        dfs();
        way.pop_back();
    }
}

int main()
{
    cin >> h >> w;
    lim[0] = {0, h};
    lim[1] = {0, w};
    lim[2] = {0, h + w - 1};
    lim[3] = {-w + 1, h};
    lefts = {1, 0, 1, 1};
    rights = {0, 1, 1, -1};
    maze.resize(h, vector<int>(w));
    cin >> maze;
    // cout << maze << endl;
    rep(i, h)
    {
        rep(j, w)
        {
            sum[0][i] += maze[i][j];
            sum[1][j] += maze[i][j];
            sum[2][i + j] += maze[i][j];
            sum[3][i - j] += maze[i][j];
        }
    }
    // rep(i, 4)
    // {
    //     cout << sum[i] << endl;
    // }
    dfs();
    cout << ans << endl;
}