#include <bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x << ' '; print(x); cerr << endl;
#else
#define dbg(x)
#endif
void print(int x) {cerr << x;}
void print(long long x) {cerr << x;}
void print(char x) {cerr << x;}
void print(string x) {cerr << x;}
void print(double x) {cerr << x;}
template <class T> void print(vector <T> x);
template <class T> void print(set <T> x);
template <class T> void print(multiset <T> x);
template <class T, class V> void print(pair <T, V> x);
template <class T, class V> void print(map <T, V> x);
template <class T> void print(vector <T> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
template <class T> void print(set <T> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
template <class T> void print(multiset <T> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
template <class T, class V> void print(pair <T, V> x) {cerr << "{"; print(x.first); cerr << ' '; print(x.second); cerr << "}";}
template <class T, class V> void print(map <T, V> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
#define ll long long
#define pb push_back
#define ppb pop_back
#define PII pair <int, int>
#define PLL pair <ll, ll>
#define all(v) (v).begin(), (v).end()
#define OK cerr << "OK\n";
#define MP make_pair
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};
const int inf = 1e9;
int biggest_stadium(int N, vector <vector <int>> F){
bool flag = 1;
int count_trees = 0;
for(int i = 0; i < N; i++){
for(int j = 0; j < N; j++){
if(!F[i][j]) continue;
count_trees++;
int cnt = 0;
for(int t = 0; t < 4; t++){
int nx = i + dx[t], ny = j + dy[t];
if(nx < 0 || ny < 0 || nx >= N || ny >= N){
//dbg(MP(i, j));
cnt++; continue;
}
cnt += F[nx][ny];
}
if(cnt <= 1){
//dbg(MP(i, j));
flag = 0;
}
}
}
if(flag){
int vis_count = 0;
for(int i = 0; i < N; i++){
bool flag = 0;
for(int j = 0; j < N; j++){
if(!F[i][j]){
flag = 1;
bool visited[2005][2005] = {0};
queue <PII> q;
q.push({i, j});
while(!q.empty()){
int x = q.front().first, y = q.front().second;
//dbg(MP(x, y));
q.pop();
if(visited[x][y]) continue;
vis_count++;
visited[x][y] = 1;
for(int t = 0; t < 4; t++){
int nx = x + dx[t], ny = y + dy[t];
if(nx < 0 || ny < 0 || nx >= N || ny >= N) continue;
if(F[nx][ny]) continue;
q.push({nx, ny});
}
}
break;
}
}
if(flag) break;
}
if(vis_count == N * N - count_trees) return N * N - count_trees;
}
return inf;
}
