#include<iostream>
using namespace std;
int a[100][100],n,i,j,k,s=-9999999999;
void citeste(int a[][100],int &n)
{
    do{
    cin>>n;
    }while(!(n>=1 && n<=50));
    for(i=1; i<=n; i++)
        for(j=1; j<=n; j++)

            do{
                    cin>>a[i][j];
            }while(!(a[i][j]>=-100 && a[i][j]<=100));
}
int suma(int a[][100],int l,int s,int d)
{
    int i=l,j=s,suma=0,dif=d-s;
    while(j<=d)
    {
        suma+=a[i][j];
        j++;
    }
    j=s;
    i=l+1;
    while(dif)
    {
        suma+=a[i][j];
        i++;
        dif--;
    }
    i--;
    j=s+1;
    while(j<=d)
    {
        suma+=a[i][j];
        j++;
    }
    dif=d-s-1;
    i--;
    j=d;
    while(dif)
    {
        suma+=a[i][j];
        i--;
        dif--;
    }
    return suma;
}
int main()
{
    citeste(a,n);
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
           if(a[i][j]>s)
           s=a[i][j];

        for(i=1; i<n; i++)
            for(k=1; k<n; k++)
                for(j=k+1; j<=n && j-k<=n-i; j++)
                    if(s<suma(a,i,k,j))
                        s=suma(a,i,k,j);
        cout<<s<<endl;

    return 0;
}