#include <cstdio>
#include <iostream>
#include <fstream>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <cstdlib>
#include <ctype.h>
#include <cstring>
#include <string>
#include <ctime>
#include <cassert>
#include <utility>

using namespace std;

int n, a[55][55], smax = -190000000, s;

int main() {
//	freopen("date.in", "r", stdin);
//	freopen("date.out","w", stdout);

	cin >> n;

	for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            cin >> a[i][j];
    smax = -190000000;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            for(int len = 0; len <= n - 1 - i; len++) {
                s = 0;
                for(int k = 0; k <= len; k++) {
                    s += a[i][j + k];
                    if(len > 0)
                        s += a[i + len][j + k];
                }
                for(int k = 0; k <= len - 2; k++) {
                    s += a[i + k + 1][j];
                    if(len > 0)
                        s += a[i + k + 1][j + len];
                }
                smax = max(smax, s);
            }
    cout << smax;
	return 0;
}