#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <map>
#include <set>
#include <climits>

using namespace std;

int N, _max;
int A[51][51];

int solve(int x, int y);

int main() {
#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
#endif
	int i, j;
	cin >> N;
	for (i = 0; i < N; ++i) {
		for (j = 0; j < N; ++j) {
			cin >> A[i][j];
		}
	}
	_max = A[0][0];
	for (i = 0; i < N; ++i) {
		for (j = 0; j < N; ++j) {
			_max = max(solve(i, j), _max);
		}
	}
	cout << _max;
#ifndef ONLINE_JUDGE
	while (1);
#endif
}

int solve(int x, int y) {
	int i, j, nx, ny, ok1;
	int s, saux;
	saux = A[x][y];
	nx = x + 1;
	ny = y + 1;
	while (nx < N && ny < N) {
		ok1 = 1;
		s = 0;
			for (i = x; i <= nx ; ++i) {
				s += A[x][y];
				s += A[x][y];
				
			}
			for (j = y + 1; j < ny; ++j) {
				 s += A[x][y];
				 s += A[x][y];
			}
			saux = max(saux, s);
	
		++nx;
		++ny;
	}
	return saux;
}