#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <string>
#include <set>
#include <map>
#include <vector>
#include <queue>
#define ll long long
#define db double
using namespace std;
ll tt,a[105][105],h,w;
pair<ll,ll> pr[1005];
bool vis[105][105];
ll getval(ll ty, ll val) {
	ll res = 0;
	if (ty == 1) {
		for (ll i = 1;i <= w;i++) {
			if (!vis[val][i]) {
				vis[val][i] = 1;
				res += a[val][i];
			}
		}
	}
	if (ty == 2) {
		for (ll i = 1;i <= h;i++) {
			if (!vis[i][val]) {
				vis[i][val] = 1;
				res += a[i][val];
			}
		}
	}
	if (ty == 3) {
		for (ll i = 1;i <= h;i++) {
			if ((val - i > w) || (val - i < 1)) {
				continue;
			}
			if (!vis[i][val - i]) {
				vis[i][val - i] = 1;
				res += a[i][val - i];
			}
		}
	}
	if (ty == 4) {
		for (ll i = 1;i <= h;i++) {
			if ((i - val > w) || (i - val < 1)) {
				continue;
			}
			if (!vis[i][i - val]) {
				vis[i][i - val] = 1;
				res += a[i][i - val];
			}
		}
	}
	return res;
}
void clr(ll ty,ll val) {
	if (ty == 1) {
		for (ll i = 1;i <= w;i++) {
			vis[val][i] = 0;
		}
	}
	if (ty == 2) {
		for (ll i = 1;i <= h;i++) {
			vis[i][val] = 0;
		}
	}
	if (ty == 3) {
		for (ll i = 1;i <= h;i++) {
			if ((val - i > w) || (val - i < 1)) {
				continue;
			}
			vis[i][val - i] = 0;
		}
	}
	if (ty == 4) {
		for (ll i = 1;i <= h;i++) {
			if ((i - val > w) || (i - val < 1)) {
				continue;
			}
			vis[i][i - val] = 0;
		}
	}
}
void solve() {
	scanf("%lld%lld",&h,&w);
	for (ll i = 1;i <= h;i++) {
		for (ll j = 1;j <= w;j++) {
			scanf("%lld",&a[i][j]);
		}
	}
	ll tot = 0;
	for (ll i = 1;i <= h;i++) {
		pr[++tot] = make_pair(1ll,i);
	}
	for (ll i = 1;i <= w;i++) {
		pr[++tot] = make_pair(2ll,i);
	}
	for (ll i = 2;i <= h + w;i++) {
		pr[++tot] = make_pair(3ll,i);
	}
	for (ll i = 1 - w;i <= h - 1;i++) {
		pr[++tot] = make_pair(4ll,i);
	}
	memset(vis,0,sizeof(vis));
	ll ans = 0;
	for (ll i = 1;i <= tot;i++) {
		for (ll j = i + 1;j <= tot;j++) {
			ll sum = 0;
			sum += getval(pr[i].first,pr[i].second);
			sum += getval(pr[j].first,pr[j].second);
			ans = max(ans,sum);
			clr(pr[i].first,pr[i].second);
			clr(pr[j].first,pr[j].second);
		}
	}
	printf("%lld\n",ans);
}
int main() {
	tt = 1;
	while(tt) {
		solve();
		tt--;
	}
	return 0;
}