#include <bits/stdc++.h>
using namespace std;
int TestCase1(int n, vector<vector<int>> a){
for (int i=0; i<n; i++){
for (int j=0; j<n; j++){
if (!a[i][j]) continue;
int h = min(i+1, n-i);
int v = min(j+1, n-j);
return n*n-h*v;
}
}
return n*n;
}
int TestCase2(int n, vector<vector<int>> a1){
int ans = 1;
auto a = a1;
for (int cd = 0; cd<(1<<(n*n)); cd++){
a = a1;
int bad = 0;
for (int i=0; i<n; i++) for (int j=0; j<n; j++)
if (a[i][j] && !(cd&(1<<(n*i+j)))) bad = 1;
if (bad) continue;
for (int i=0; i<n; i++) for (int j=0; j<n; j++) a[i][j] = (bool) (cd & (1<<(n*i+j)));
for (int x1 = 0; x1<n; x1++) for (int y1 = 0; y1<n; y1++){
if (a[x1][y1]) continue;
for (int x2 = 0; x2<n; x2++) for (int y2 = 0; y2<n; y2++){
if (a[x2][y2]) continue;
if (x1==x2 && y1==y2) continue;
if (x1 == x2){
for (int j=min(y1,y2); j<max(y1,y2); j ++){
if (a[x1][j]) bad = 1;
}
}
if (y1 == y2){
for (int i=min(x1,x2); i<max(x1,x2); i++){
if (a[i][y1]) bad =1;
}
}
if (a[x1][y2] && a[x2][y1]) bad = 1;
if (bad) break;
}
if (bad) break;
}
if (bad) continue;
ans = max(ans, n*n - __builtin_popcount(cd));
}
return ans;
}
struct segment{
int l, r;
bool operator == (segment u){
return l == u.l && r==u.r;
}
bool operator >= (segment u){
if (u.l == -1) return 1;
if (l==-1) return 0;
return l<=u.l && r>=u.r;
}
bool operator *(segment u){
if (l==-1 || u.l ==-1) return 1;
if (l<u.l && r<u.r) return 0;
if (l>u.l && r>u.r) return 0;
return 1;
}
};
int Partial(int n, vector<vector<int>> a){
vector<segment> sts(n);
int cnt = 0;
for (int i=0; i<n; i++){
int st = 0;
for (int j=0; j<n; j++){
cnt+=!a[i][j];
if (!a[i][j] && !st){
st = 1; sts[i].l = j; sts[i].r = j;
} else if (!a[i][j] && st==1){
sts[i].r = j;
} else if (a[i][j] && st==1){
st = 2;
} else if (a[i][j] && !st) {}
else if (a[i][j] && st==2) {}
else return -1;
}
}
for (int i=0; i<n-1; i++){
int d = 0;
if (!(sts[i] * sts[i+1])) return -1;
if (sts[i] == sts[i+1]) continue;
if (sts[i]>=sts[i+1] && d) return -1;
if (sts[i]>=sts[i+1] && !d) d=1;
}
return cnt;
}
int biggest_stadium(int n, vector<vector<int>> a){
if (n<4) return TestCase2(n,a);
int ones = 0;
for(int i=0; i<n; i++) for (int j=0; j<n; j++) ones+=a[i][j];
if (ones<=1) return TestCase1(n,a);
return Partial(n,a);
}
