#include <bits/stdc++.h>

using namespace std;

using i64 = long long;

void solve() {
    int n;
    cin >> n;
    vector<vector<int>>a(n + 1, vector<int>(n + 1));
    int x = 0, y = 0;
    for (int i = 1;i <= n;i ++){
        for (int j = 1;j <= n;j ++){
            cin >> a[i][j];
            if (a[i][j] == -1){
                x = i, y = j;
            }
        }
    }

    int res = 0;  
    int b = -1, c = -1, d = -1, e = -1;// 左上右下
    if (x > 1){
        b = a[x - 1][y];
    }
    if (y > 1){
        c = a[x][y - 1];
    }
    if (x < n){
        d = a[x + 1][y];
    }
    if (y < n){
        e = a[x][y + 1];
    }

    if (b != -1 || d != -1){
        int t = 0x3f3f3f3f;
        if (b != -1){
            t = min(t, b);
        }
        if (d != -1){
            t = min(t, d);
        }
        res += t;
    }
    if (c != -1 || e != -1){
        int t = 0x3f3f3f3f;
        if (c != -1){
            t = min(c, t);
        }
        if (e != -1){
            t = min(e, t);
        }
        res += t;
    }
    cout << res << "\n";

}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T = 1;
    // cin >> T;
    while (T--) {
        solve();
    }
    return 0;
}