#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;

bool check(vector < vi > &F) {
	int N = sz(F);
	vector < pair < int, int > > vc;
	L(i, 0, N - 1) {
		int l = 0;
		while(l < N && F[i][l]) ++l;
		int r = N - 1;
		while(r >= 0 && F[i][r]) --r;
		if(l > r) continue;
		L(j, l, r) {
			if(F[i][j]) {
				return 0;
			}
		} 
		vc.emplace_back(l, r);
	} 
	
	for(auto &u : vc) 
		for(auto &v : vc) {
			int lenl = u.second - u.first + 1;
			int lenr = v.second - v.first + 1;
			int mn = min(u.second, v.second) - max(u.first, v.first) + 1;
			if(mn != min(lenl, lenr)) {
				return false;
			}
		}
	return true;
}

int biggest_stadium(int N, vector < vi > F) {
	int all = 0;
	L(i, 0, N - 1) {
		L(j, 0, N - 1) {
			if(!F[i][j]) {
				++all;
			}
		}
	}
	if(!check(F)) 
		return false;
	L(i, 0, N - 1) {
		L(j, i + 1, N - 1) {
			swap(F[i][j], F[j][i]);
		}
	}
	if(!check(F)) 
		return false;
	return all;
}

//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}});
//}