#include <iostream>
#include <fstream>
#include <algorithm>
#include <bitset>
#include <cstdio>
#include <vector>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>


#define DN 55
#define pb push_back
#define mp make_pair
#define per pair<int,int>
#define INF (1<<30)
#define LL long long
#define un unsigned
#define x first
#define y second
#define f cin
using namespace std;


int h[DN][DN],sum_l[DN][DN],sum_col[DN][DN];

int main()
{
    int n,rez=-(1<<30);
   // ifstream f("test.in");
    f>>n;
    for(int i=1;i<=n;++i)
        for(int j=1;j<=n;++j){

            f>>h[i][j];
            sum_l[i][j]=h[i][j]+sum_l[i][j-1];
            sum_col[i][j]=h[i][j]+sum_col[i-1][j];
        }
    if(n==1){
        cout<<h[1][1];
        return 0;
    }
    for(int t=1;t<=n;++t)
        for(int i=1;i+t<=n;++i)
            for(int j=1;j+t<=n;++j){

               //cout<<i<<" "<<j<<" T :"<<t<<endl;
                int tmp = sum_l[i][j+t] - sum_l[i][j-1];
                tmp+=sum_l[i+t][j+t] - sum_l[i+t][j-1];

                //cout<<"a:"<<a<<" B:"<<b<<endl;

                tmp+=sum_col[i+t-1][j] - sum_col[i][j];
                tmp+=sum_col[i+t-1][j+t] - sum_col[i][j+t];

                if(tmp>rez)
                    rez=tmp;
            }

    cout<<rez;

    return 0;
}