#include <cstdio>
using namespace std;

int n, a[101][101], s[101][101], sc[101][101];
int main()
{
    freopen("maxsquare.in", "r", stdin);
    freopen("maxsquare.out", "w", stdout);
    scanf("%d", &n);
    int Max = -2000000000;
    for(int i = 1; i <= n ; ++i){
        for(int j = 1; j <= n ; ++j){
            scanf("%d", &a[i][j]);
            s[i][j] += s[i][j - 1] + a[i][j];
            sc[i][j] += sc[i - 1][j] + a[i][j];
            if(a[i][j] > Max) Max = a[i][j];
        }
    }
    for(int t = 1; t < n ; ++t){
        for(int i = 1; i <= n - t; ++i){
            for(int j = 1; j <= n - t ; ++j){
                int Sum = (s[i + t][j + t] + s[i][j + t] - s[i][j - 1] - s[i + t][j - 1]);
                Sum = Sum + sc[i + t - 1][j] - sc[i][j] + sc[i + t - 1][j + t] - sc[i][j + t];
                if(Sum > Max)
                    Max = Sum;
            }
        }
    }
    printf("%d", Max);
    return 0;
}