#include <cstdio>
#include <cstring>
using namespace std;

int a[128][128];
int sp[128][128];

int main(int argc, char *argv[])
{
    freopen("maxsum.in", "r", stdin);
    freopen("maxsum.out", "w", stdout);
    memset(a, 0, sizeof(a));
    memset(sp, 0, sizeof(sp));
    int n;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++)
        for (int j = 0; j <= n; j++)
            scanf("%d", &a[i][j]);

    for (int i = 1; i <= n; i++)
    {
        int s = 0;
        for (int j = 1; j <= n; j++)
        {
            s += a[j][i];
            sp[j][i] = s;
        }
    }

    int smax2 = a[1][1], smax = 0;
    int sc = 0;
    for (int i1 = 1; i1 <= n; i1++)
    {
        for (int i2 = 1; i2 <= n; i2++)
        {
            smax = sc = sp[i2][1] - sp[i1 - 1][1];
            for (int j = 2; j <= n; j++)
            {
                if (sc + sp[i2][j] - sp[i1 - 1][j] > sp[i1][j] - sp[i1 - 1][j])
                    sc = sc + sp[i2][j] - sp[i1 - 1][j];
                else
                    sc = sp[i2][j] - sp[i1 + 1][j];
                if (sc > smax)
                    smax = sc;
            }
            if (smax > smax2)
                 smax2 = smax;
                    }
    }
    printf("%d\n", smax2);
    return 0;
}