#pragma comment(linker, "/STACK:1024000000,1024000000")#include <cstdio>#include <string>#include <cstdlib>#include <cmath>#include <iostream>#include <cstring>#include <set>#include <queue>#include <algorithm>#include <vector>#include <map>#include <cctype>#include <cmath>#include <stack>#include <list>#include <sstream>#define frer freopen("in.txt", "r", stdin)#define frew freopen("out.txt", "w", stdout)using namespace std;typedef long long LL;typedef pair<int, int> P;const int INF = 0x3f3f3f3f;const double inf = 0x3f3f3f3f3f3f;const double PI = acos(-1.0);const double eps = 1e-8;const int maxn = 5e2 + 5;const int mod = 1e9 + 7;const int dr[] = {-1, 1, 0, 0, 1, 1, -1, -1};const int dc[] = {0, 0, 1, -1, 1, -1, 1, -1};const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};int n, m;const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};inline int Min(int a, int b){ return a < b ? a : b; }inline int Max(int a, int b){ return a > b ? a : b; }inline LL Min(LL a, LL b){ return a < b ? a : b; }inline LL Max(LL a, LL b){ return a > b ? a : b; }inline bool is_in(int r, int c){    return r >= 0 && r < n && c >= 0 && c < m;}LL a[maxn][maxn];int main(){    while(cin >> n){        memset(a, 0, sizeof a);        LL sum1 = 0, sum2 = 0;        int x, y;        for(int i = 0; i < n; ++i){            for(int j = 0; j < n; ++j){                scanf("%I64d", &a[i][j]);                a[i][n] += a[i][j];                a[n][j] += a[i][j];                if(a[i][j] == 0)  x = i, y = j;                if(i == j)  sum1 += a[i][j];                if(i + j == n - 1)  sum2 += a[i][j];            }        }        if(1 == n)  printf("1\n");        else{            LL ans = 0;            for(int i = 0; i < n; ++i){                if(i != x){                    ans = a[i][n] - a[x][n];                    a[x][n] += ans;                    a[n][y] += ans;                    if(x == y)  sum1 += ans;                    if(x + y == n - 1)  sum2 += ans;                    break;                }            }            bool ok = true;            if(sum1 != sum2 || ans < 1 || ans > 1e18) ok = false;            if(!ok){  printf("-1\n"); continue;  }            for(int i = 0; i < n; ++i){                if(a[i][n] != sum1 || a[n][i] != sum1){  ok = false; break; }            }            if(!ok){  printf("-1\n"); continue;  }            else cout << ans << endl;        }    }    return 0;}