#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstring>
#include <math.h> 
#define lli long long int



using namespace std;

int main(){
	int n;
	cin >> n;
	lli a[n][n];
	int i = 0;
	int j = 0;
	int x, y;
	lli xsum = 0;
	lli ysum = 0;
	lli diag1 = 0;
	lli diag2 = 0;
	lli checksum = 0;
	for(int i = 0; i < n; i++){
		for(int j = 0; j < n; j++){
			cin >> a[i][j];
			if(a[i][j] == 0){
				x = i;
				y = j;
			}
		}
	}
	for(int j = 0; j < n; j++){
		xsum += a[x][j];
		checksum += a[x+1][j];
	}
	for(int j = 0; j < n; j++){
	
		ysum += a[j][y];
	}
	int f = n-1;
	int t = 0;
	diag1 = a[0][0];
	diag2 = a[n-1][0];
	if(x == y){
		for(int i = 0; i < n; i++){
			for(int j = 1; j < n-1; j++){
				diag1 += a[i+1][j];
			}

		}
	
		if(diag1 == xsum && xsum == ysum){
			cout << abs(xsum - checksum);
			return 0;
		}
		else{
			cout << -1;
			return 0;
		}
	}
	else if(abs(f-y) == abs(x-t)){
		for(int i = n-1; i > 1; i--){
			for(int j = 1; j < n-2; j++){
				diag2 += a[i][j];
			}
		}
		
		if(diag2 == xsum && xsum == ysum){
			cout << abs(xsum - checksum);
			return 0;
		}
		else{
			cout << -1;
			return 0;
		}
	}
	else{
		if(xsum == ysum){
			cout << abs(checksum - xsum) << endl;

		}

	}


}