#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ld=long double;
ld pie=3.141592653589793;
ll mod=998244353;
ll inf=10000000000000;//10^17
int main(){
    ll h,w;
    cin >> h >> w;
    vector<vector<ll>>a(h+2,vector<ll>(w+2));
    for (ll i = 0; i < h; i++)
    {
        for (ll j = 0; j < w; j++)
        {
            cin >> a[i+1][j+1];
        }
    }
    ll now=0;
    vector<vector<ll>>memo(h+2,vector<ll>(w+2,0));
    ll x=0,y=0;
    ll d=0;
    ll ans=0;
    while (1)
    {
        ll xx=0,yy=0;
        ll dd=0;
        while (1)
        {
            for (ll i = -1; i <=1; i++)
            {
                for (ll j = -1; j <=1; j++)
                {
                    if (i==0&&j==0)
                    {
                        continue;
                    }
                    for (ll k = -1; k <=1; k++)
                    {
                        for (ll l = -1; l <=1; l++)
                        {
                            ll aa=0;
                            if (k==0&&l==0)
                            {
                                continue;
                            }
                            now++;
                            for (ll n = 1; n >=0; n++)
                            {
                                if (x+i*n<=0||x+i*n>=h+1||y+j*n<=0||y+j*n>=w+1)
                                {
                                    break;
                                }
                                memo[x+i*n][y+j*n]=now;
                                aa+=a[x+i*n][y+j*n];
                            }
                            for (ll n = 1; n >=0; n++)
                            {
                                if (xx+k*n<=0||xx+k*n>=h+1||yy+l*n<=0||yy+l*n>=w+1)
                                {
                                    break;
                                }
                                if (memo[xx+k*n][yy+l*n]!=now)
                                {
                                    aa+=a[xx+k*n][yy+l*n];
                                }
                            }
                            ans=max(ans,aa);
                            now++;
                        }
                    }
                }
            }
        if (dd==0)
        {
            yy++;
            if (yy==w+1)
            {
                dd=1;
            }
        }else if (dd==1)
        {
            xx++;
            if (xx==h+1)
            {
                dd=2;
            }
        }else if (dd==2)
        {
            yy--;
            if (yy==0)
            {
                dd=3;
            }
        }else{
            xx--;
            if (xx==-1)
            {
                break;
            }
        }
        }
        if (d==0)
        {
            y++;
            if (y==w+1)
            {
                d=1;
            }
        }else if (d==1)
        {
            x++;
            if (x==h+1)
            {
                d=2;
            }
        }else if (d==2)
        {
            y--;
            if (y==0)
            {
                d=3;
            }
        }else{
            x--;
            if (x==-1)
            {
                break;
            }
            
        }
    }
    cout << ans << endl;
}