#include <iostream>
#include <vector>

using namespace std;

int main() {
    int n;
    cin >> n;
    vector<vector<int>> v(n, vector<int>(n));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            cin >> v[i][j];
        }
    }
    long long sum = 0;
    for (int j = 0; j < n; j++) {
        sum += v[0][j];
    }
    for (int i = 0; i < n; i++) {
        int tmp = 0;
        for (int j = 0; j < n; j++) {
            tmp += v[i][j];
        }
        if (sum != tmp) {
            cout << -1 << endl;
            return 0;
        }
    }
    for (int j = 0; j < n; j++) {
        int tmp = 0;
        for (int i = 0; i < n; i++) {
            tmp += v[i][j];
        }
        if (sum != tmp) {
            cout << -1 << endl;
            return 0;
        }
    }
    for (int i = 0; i < 2 * n - 1; i++) {
        int tmp = 0;
        for (int j = 0; j <= i; j++) {
            if (i < n && j < n) {
                tmp += v[i][j];
            }
        }
        if (tmp != sum) {
            cout << -1 << endl;
            return 0;
        }
    }
    cout << 1 << endl;
    return 0;
}