#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0;i<(int)(n);i++)

int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int h,w;
	cin>>h>>w;
	array<array<int,100>,100> a;
	rep(i,h) rep(j,w) cin>>a[i][j];
	array<int,4> dx={-1,0,1,1};
	array<int,4> dy={1,1,1,0};
	auto isok=[&](int x,int y){
		return 0<=x&&x<h&&0<=y&&y<w;
	};
	ll ans=0;
	rep(ch1,h+w-1){
		int x1=0,y1=0;
		if(ch1>=h) y1=ch1-h+1;
		else x1=ch1;
		rep(lp,2){
			for(int ch2=ch1;ch2<h+w-1;ch2++){
				int x2=0,y2=0;
				if(ch2>=h) y2=ch2-h+1;
				else x2=ch2;
				rep(rp,2){
					rep(i,4){
						rep(j,4){
							set<int> stl;
							ll res=0;
							int cx1=x1,cy1=y1,cx2=x2,cy2=y2;
							while(isok(cx1,cy1)){
								res+=a[cx1][cy1];
								stl.insert(cx1+cy1*h);
								cx1+=dx[i];
								cy1+=dy[i];
							}
							while(isok(cx2,cy2)){
								if(!stl.count(cx2+cy2*h)){
									res+=a[cx2][cy2];
								}
								cx2+=dx[j];
								cy2+=dy[j];
							}
							ans=max(ans,res);
						}
					}
					if(x2!=0) break;
					x2=h-1;
				}
			}
			if(x1!=0) break;
			x1=h-1;
		}
	}
	cout<<ans<<endl;
}