#include<iostream>
#include<vector>
#include<cassert>
using namespace std;
int H,W;
int A[100][100];
int vis[100][100];
int d[3]={0,1,-1};
void f(pair<int,int>z,int dr,vector<pair<int,int> >&now)
{
	int dx=d[dr/3],dy=d[dr%3];
	int x=z.first,y=z.second;
	do{
		x+=dx,y+=dy;
		if(0<=x&&x<H&&0<=y&&y<W)now.push_back(make_pair(x,y));
		else break;
	}while(true);
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin>>H>>W;
	for(int i=0;i<H;i++)for(int j=0;j<W;j++)cin>>A[i][j];
	vector<pair<int,int> >OUT;
	for(int i=-1;i<=H;i++)
	{
		OUT.push_back(make_pair(i,-1));
		OUT.push_back(make_pair(i,W));
	}
	for(int j=0;j<W;j++)
	{
		OUT.push_back(make_pair(-1,j));
		OUT.push_back(make_pair(H,j));
	}
	vector<pair<int,int> >now;
	int visT=0;
	int ans=0;
	for(int P=0;P<OUT.size();P++)for(int Q=P+1;Q<OUT.size();Q++)
	{
		for(int p=1;p<9;p++)for(int q=1;q<9;q++)
		{
			now.clear();
			f(OUT[P],p,now);
			f(OUT[Q],q,now);
			visT++;
			int ret=0;
			for(pair<int,int>z:now)
			{
				int x=z.first,y=z.second;
				if(vis[x][y]<visT)
				{
					vis[x][y]=visT;
					ret+=A[x][y];
				}
			}
			ans=max(ans,ret);
		}
	}
	cout<<ans<<endl;
}