#include <stdio.h>
 
int min(int a, int b) {
    return a < b ? a : b;
}
 
int max(int a, int b) {
    return a > b ? a : b;
}
 
int collect_max_nuts(int n, int forest[n][n]) {
    int max_nuts = 0;
 
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            int max_dist = min(i, n - 1 - i) + min(j, n - 1 - j);  // Manhattan distance to forest boundary
            int nuts = forest[i][j];
 
            for (int x = 0; x < n; x++) {
                for (int y = 0; y < n; y++) {
                    int dist = abs(i - x) + abs(j - y);
                    if (dist <= max_dist) {
                        nuts += forest[x][y];
                    }
                }
            }
 
            max_nuts = max(max_nuts, nuts);
        }
    }
 
    return max_nuts;
}
 
int main() {
    int n;
    scanf("%d", &n);
    int forest[n][n];
 
    // Read input
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            scanf("%d", &forest[i][j]);
        }
    }
 
    // Find the maximum number of nuts the squirrel can collect
    int max_nuts = collect_max_nuts(n, forest);
    printf("%d\n", max_nuts);
 
    return 0;
}