B

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;

#define REP(i,n) for(int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define FORD(i,a,b) for(int i=(a);i>(b);i--)
typedef long long ll;
typedef unsigned ui;
typedef unsigned long long ull;

int nextint()
{
    int t;
    if(scanf("%d",&t)!=1)
    {
        fprintf(stderr,"Failed to read int\n");
        exit(0);
    }
    return t;
}
int n;
int a[400][400];
int sum[2*400][401];
int id[400][400];

int main()
{
    n=nextint();
    REP(i,n) REP(j,n) a[i][j]=nextint();
    REP(i,2*n-1)
    {
         int top=1;
         REP(j,n) REP(k,n)
            if(j+k==i)
            {
                sum[i][top]=sum[i][top-1]+a[j][k];
                id[j][k]=top;
                top++;
            }
    }
    int res=-1000000000;
    REP(i,n) REP(j,n)
    {
        int s=0;
        REP(k,n)
        {
            if(i+k==n||j+k==n) break;
            s+=a[i+k][j+k];
            res=max(res,s-(sum[i+j+k][id[i+k][j]]-sum[i+j+k][id[i][j+k]-1]));
        }
    }
    printf("%d\n",res);
}