#include <stdio.h>

int n;
int v[105][105];

int main ()
{
#ifndef ONLINE_JUDGE
	freopen ("mind2a.in", "r", stdin);
	freopen ("mind2a.out", "w", stdout);
#endif

	scanf ("%d", &n);
	
	int i, j, k, l;
	int sol = -1000000000;
	
	for (i = 1; i <= n; i ++)
		for (j = 1; j <= n; j ++)
			scanf ("%d", &v[i][j]);
	
	for (i = 1; i <= n; i ++)
		for (j = 1; j <= n; j ++)
		{
			if (v[i][j] > sol)
				sol = v[i][j];
			for (k = 2; i + k - 1 <= n && j + k - 1 <= n; k ++)
			{
				int s = 0;
				for (l = i; l <= i + k - 1; l ++)
					s += v[l][j] + v[l][j + k - 1];
				for (l = j + 1; l < j + k - 1; l ++)
					s += v[i][l] + v[i + k - 1][l];
				if (s > sol)
					sol = s;
			}
		}
	printf ("%d\n", sol);
	return 0;
}