#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <limits.h>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef set<int> si;
typedef set<ii> sii;
#define MP make_pair
#define PB push_back
#define REP(i,a) for (int i = 0; i < int(a); i++)
#define FOR(i,a,b) for ( int i = int(a); i <= int(b); ++i )
#define FORD(i,a,b) for ( int i = int(a); i >= int(b); --i )
#define TR(c,it) for( typeof(c.begin()) it = c.begin(); it != c.end(); ++it )
#define TRR(c,it) for( typeof(c.rbegin()) it = c.rbegin(); it != c.rend(); ++it )

const int INF = 1<<29;
typedef long long int lli;

const int MAXROW = 100;
const int MAXCOL = 100;

int matrix[MAXROW][MAXCOL];

int kadane( int * arr, int & start, int & finish, int n )
{
	int sum = 0, maxSum = INT_MIN;
	finish = -1;

	int local_start = 0;
	FOR( i, 0, n-1 )
	{
		sum += arr[i];
		if ( sum < 0 )
		{
			sum = 0;
			local_start = i + 1;
		}
		else if ( sum > maxSum )
		{
			maxSum = sum;
			start  = local_start;
			finish = i;
		}
	}
	if ( finish != -1 )
		return maxSum;
	maxSum = arr[0];
	start = finish = 0;
	FOR( i, 1, n-1 )
	{
		if ( sum > maxSum )
		{
			maxSum = sum;
			start = finish = i;
		}
	}
	return maxSum;
}

int findMaxSum( int row, int col )
{
	int maxSum = INT_MIN, finalLeft, finalRight, finalTop, finalBottom;
	int left, right;
	int temp[row], sum, start, finish;

	FOR( left, 0, col - 1 )
	{
		memset( temp, 0, sizeof(temp) );
		FOR( right, left, col-1 )
		{
			FOR( i, 0, row-1 )
				temp[i] += matrix[i][right];
			sum = kadane( temp, start, finish, row );
			if ( sum > maxSum )
			{
				maxSum      = sum;
				finalLeft   = left;
				finalRight  = right;
				finalTop    = start;
				finalBottom = finish;
			}
			maxSum = max( sum, maxSum );
		}
	}
	return maxSum;
}

int main( )
{
	int n;

	while ( scanf("%d", &n) == 1 )
	{
		FOR( i, 0, n-1 )
			FOR( j, 0, n-1 )
				scanf("%d", &matrix[i][j]);
		printf("%d\n", findMaxSum( n, n ));
	}


	return 0;
}