#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

template<typename T>
vector<vector<T>> vec2d(int n, int m, T v){
    return vector<vector<T>>(n, vector<T>(m, v));
}

template<typename T>
vector<vector<vector<T>>> vec3d(int n, int m, int k, T v){
    return vector<vector<vector<T>>>(n, vector<vector<T>>(m, vector<T>(k, v)));
}

template<typename T>
void print_vector(vector<T> v, char delimiter=' '){
    if(v.empty()) {
        cout << endl;
        return;
    }
    for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter;
    cout << v.back() << endl;
}

using P = pair<int, int>;
using T = tuple<int, int, int>;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    int h, w; cin >> h >> w;
    auto a = vec2d(h, w, 0);
    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            cin >> a[i][j];      
        }
    }
    vector<P> ps = {
        {1, -1},
        {1, 0},
        {1, 1},
        {0, 1},
    };
    map<T, int> mp;
    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            for(auto [s, t]: ps){
                int x = s*i+t*j;
                T key = {x, s, t};
                if(mp.count(key)) mp[key] += a[i][j];
                else mp[key] = a[i][j];
            }
        }
    }
    int ans = 0;
    for(auto [k0, v0]: mp){
        auto [x0, s0, t0] = k0;
        for(auto [k1, v1]: mp){
            auto [x1, s1, t1] = k1;
            if(k0 == k1){
                chmax(ans, v0);
                continue;
            }
            if(s0 == s1 && t0 == t1){
                chmax(ans, v0+v1);
                continue;
            }
            int P = x0*t1-t0*x1;
            int Q = s0*x1-s1*x0;
            int R = s0*t1-t0*s1;
            if(P%R == 0 && Q%R == 0){
                int x = P/R, y = Q/R;
                if(0 <= x && x < h && 0 <= y && y < w){
                    chmax(ans, v0+v1-a[x][y]);
                    continue;
                }
            }
            chmax(ans, v0+v1);
        }
    }
    cout << ans << endl;
}