#include <bits/stdc++.h>
using namespace std;
const int N = 310;

int a[N][N], s[N][N], dp[N];
int n, ans;

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++) {
            cin >> a[i][j];
            s[i][j] = s[i - 1][j] + a[i][j];
        }

    for (int i = 1; i <= n; i++) {
        for (int k = 1; k <= i; k++) {
            for (int j = 1; j <= n; j++) {
                int gap = s[i][j] - s[i - k][j];
                dp[j] = max(dp[j - 1] + gap, gap);
                ans = max(dp[j], ans);
            }
        }
    }
    cout << ans;
    return 0;
}