#include <bits/stdc++.h>
using namespace std;

const int N = 330;
int n;
int a[N][N], dp[N];
int res = INT_MIN;

int main() {
    cin >> n;
    // 前缀和(竖直方向)
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            cin >> a[i][j];
            a[i][j] += a[i - 1][j];
        }
    }
    // 降维变成一维dp
    for (int i = 0; i <= n - 1; i++) {
        for (int j = i + 1; j <= n; j++) {
            for (int k = 1; k <= n; k++) {
                dp[k] = max(a[j][k] - a[i][k], dp[k - 1] + a[j][k] - a[i][k]);
                res = max(res, dp[k]);
            }
        }
    }

    cout << res;

    return 0;
}