#include "bits/stdc++.h"
//#define int long long
#define all(v) v.begin() , v.end()
#define sz(a) (int)a.size()
using namespace std;
#include "soccer.h"
//int dp[8][8][8][8][8][8];
vector<vector<int>> ar;
int ans=0,n;
const int INF = 1e7;
/*int calc(int a,int b,int c,int d,int e,int f){
if(dp[a][b][c][d][e][f]!=-1) return dp[a][b][c][d][e][f];
int cevv=0;
for(int i=b;i<=c;i++) if(ar[a][i]) return dp[a][b][c][d][e][f]=-INF;
for(int i=e;i<=f;i++) if(ar[d][i]) return dp[a][b][c][d][e][f]=-INF;
if(a>0){
for(int i=0;i<n;i++){
for(int j=i;j<n;j++){
if(ar[a-1][j]) break;
if(b<=i && j<=c && ((i<=e && f<=j) || (e<=i && j<=f)) ) cevv=max(cevv,calc(a-1,i,j,d,e,f)+j-i+1);
}
}
}
if(d+1<n){
for(int i=0;i<n;i++){
for(int j=i;j<n;j++){
if(ar[d+1][j]) break;
if(e<=i && j<=f && ((i<=b && c<=j) || (b<=i && j<=c)) ) cevv=max(cevv,calc(a,b,c,d+1,i,j)+j-i+1);
}
}
}
return dp[a][b][c][d][e][f]=cevv;
}*/
int biggest_stadium(int N, vector<vector<int>> xd){
//memset(dp,-1,sizeof(dp));
ar=xd;n=N;
/*if(n<=7){
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
for(int k=j;k<n;k++){
if(ar[i][k]) break;
ans=max(ans,calc(i,j,k,i,j,k)+k-j+1);
}
}
}
return ans;
}*/
array<int,2> row[n],col[n];
int ilk_row=-1,son_row=-1,ilk_col=-1,son_col=-1;
for(int i=0;i<n;i++){
array<int,2> lol={-1,-1};
for(int j=0;j<n;j++){
if(!ar[i][j]){
if(lol[0]==-1) lol={j,j};
else if(lol[1]==j-1) lol[1]++;
else return -1;
}
}
row[i]=lol;
if(ilk_row==-1 && row[i][0]!=-1) ilk_row=i;
if(row[i][0]!=-1) son_row=i;
}
for(int i=ilk_row+1;i<=son_row;i++){
bool ok=0,ok2=0;
if(row[i][0]==-1) return -1;
if(row[i][0]<=row[ilk_row][0] && row[ilk_row][1]<=row[i][1]) ok2=1;
if(row[ilk_row][0]<=row[i][0] && row[i][1]<=row[ilk_row][1]) ok2=1;
if(row[i-1][0]<=row[i][0] && row[i][1]<=row[i-1][1]) ok=1;
if(row[i][0]<=row[i-1][0] && row[i-1][1]<=row[i][1]) ok=1;
if(!ok || !ok2) return -1;
}
for(int j=0;j<n;j++){
array<int,2> lol={-1,-1};
for(int i=0;i<n;i++){
if(!ar[i][j]){
if(lol[0]==-1) lol={i,i};
else if(lol[1]==i-1) lol[1]++;
else return -1;
}
}
col[j]=lol;
if(ilk_col==-1 && col[j][0]!=-1) ilk_col=j;
if(col[j][0]!=-1) son_col=j;
}
for(int i=ilk_col+1;i<=son_col;i++){
bool ok=0,ok2=0;
if(col[i][0]==-1) return -1;
if(col[i][0]<=col[ilk_col][0] && col[ilk_col][1]<=col[i][1]) ok2=1;
if(col[ilk_col][0]<=col[i][0] && col[i][1]<=col[ilk_col][1]) ok2=1;
if(col[i-1][0]<=col[i][0] && col[i][1]<=col[i-1][1]) ok=1;
if(col[i][0]<=col[i-1][0] && col[i-1][1]<=col[i][1]) ok=1;
if(!ok || !ok2) return -1;
}
int cnt=0;
for(int i=0;i<n;i++)
for(int j=0;j<n;j++) cnt+=(ar[i][j]==0);
return cnt;
}
/*void _(){
int nn; cin >> nn;
vector<vector<int>> v(nn,vector<int>(nn));
for(int i=0;i<nn;i++){
for(int j=0;j<nn;j++){
cin >> v[i][j];
}
}
cout << biggest_stadium(nn,v) << '\n';
}
int32_t main(){
cin.tie(0); ios::sync_with_stdio(0);
int tc=1;//cin >> tc;
while(tc--) _();
return 0;
}*/
