#include<bits/stdc++.h>
#define L(i, j, k) for(int i = (j); i <= (k); i++)
#define R(i, j, k) for(int i = (j); i >= (k); i--)
#define ll long long
#define ull unsigned long long 
#define sz(a) ((int) a.size())
#define vi vector<int>
#define me(a, x) memset(a, x, sizeof(a))
using namespace std;

int biggest_stadium(int N, vector < vi > F) {
	int ret = 0;
	int all = 0;
	
	vi Lvis(N), Rvis(N);
	L(i, 0, N - 1) 
		L(j, 0, N - 1) if(F[i][j] == 0) {
			Lvis[i] = 1;
			Rvis[j] = 1;
			all += F[i][j] == 0;
		}
	int cntl = 0, cntr = 0;
	L(i, 0, N - 1) 
		cntl += Lvis[i] == 1, cntr += Rvis[i] == 1;
	int winl = 0, winr = 0;
	L(i, 0, N - 1) {
		int cnt = 0;
		L(j, 0, N - 1) {
			cnt += F[i][j] == 0;
		}
		if(cnt == cntl) {
			winl = 1;
		}
		L(j, 0, N - 2) {
			cnt -= F[i][j] == 0 && F[i][j + 1] == 0;
		}
		if(cnt > 1) return 0;
	} 
	L(i, 0, N - 1) {
		int cnt = 0;
		L(j, 0, N - 1) {
			cnt += F[j][i] == 0;
		}
		if(cnt == cntr) {
			winr = 1;
		}
		L(j, 0, N - 2) {
			cnt -= F[j][i] == 0 && F[j + 1][i] == 0;
		}
		if(cnt > 1) return 0;
	} 
	if(winl && winr)
		return all;
	else 	
		return 0;
}

//int main() {
//	cout << biggest_stadium(5, {vi{0, 0, 0, 0, 0}, 
// vi{0, 0, 0, 0, 0}, 
// vi{0, 0, 0, 0, 0}, 
// vi{0, 0, 0, 0, 0}, 
// vi{0, 0, 0, 0, 0}});
//}