#include<bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){ 
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
       
    int h,w;
    cin>>h>>w;

    vector<pair<int,int>> use;
    for(int i = 0;i<=w+1;i++) use.push_back(make_pair(0,i));
    for(int i = 0;i<=w+1;i++) use.push_back(make_pair(h+1,i));
    for(int i = 0;i<=h+1;i++) use.push_back(make_pair(i,0));
    for(int i = 0;i<=h+1;i++) use.push_back(make_pair(i,w+1));

    int dx[] = {1,1,1,0,0,-1,-1,-1};
    int dy[] = {0,1,-1,1,-1,0,1,-1};
    int ans = 0;
    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];

    for(int i = 0;i<use.size();i++){
        for(int ii = 0;ii<8;ii++){
            vector<vector<int>> vis(h+2,vector<int>(w+2,0));
            int k = 1;
            int sum = 0;
            while(true){
                int ni = use[i].first + k * dx[ii];
                int nj = use[i].second + k * dy[ii];
                if(ni<0||ni>h+1||nj<0||nj>w+1) break;
                vis[ni][nj]++;
                sum += a[ni][nj];
                k++;
            }
            ans = max(ans,sum);
            for(int j = 0;j<use.size();j++){
                for(int jj = 0;jj<8;jj++){
                    int k = 1;
                    int now = sum;
                    while(true){
                        int ni = use[j].first + k * dx[jj];
                        int nj = use[j].second + k * dy[jj];
                        if(ni<0||ni>h+1||nj<0||nj>w+1) break;
                        k++;
                        if(vis[ni][nj]==0) now += a[ni][nj];
                    }
                    ans = max(ans,now);
                }
            }
        }
    }
    cout<<ans<<endl;
}