#include "soccer.h"
#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> BI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

int bf(int N, std::vector<std::vector<int>> F) {
    vector<PII> rg;
    rep(i,0,N) {
        int pl=N+1,pr=-1;
        rep(j,0,N) {
            if (F[i][j]==0) pl=min(pl,j),pr=max(pr,j);
        }
        if (pl<=pr) {
            rg.pb(mp(pl,pr));
            rep(j,pl,pr+1) if (F[i][j]==1) { return 0; }
        }
    }
    for (auto q1:rg) for (auto q2:rg) {
        auto p1=q1,p2=q2;
        if (p1>p2) swap(p1,p2);
        if (p1.fi<p2.fi&&p1.se<p2.se) return 0;
    }
    rg.clear();
    rep(j,0,N) {
        int pl=N+1,pr=-1;
        rep(i,0,N) {
            if (F[i][j]==0) pl=min(pl,i),pr=max(pr,i);
        }
        if (pl<=pr) {
            rg.pb(mp(pl,pr));
            rep(i,pl,pr+1) if (F[i][j]==1) { return 0; }
        }
    }
    for (auto q1:rg) for (auto q2:rg) {
        auto p1=q1,p2=q2;
        if (p1.fi<p2.fi&&p1.se<p2.se) return 0;
    }
    int r=0;
    rep(i,0,N) rep(j,0,N) {
        if (F[i][j]==0) ++r;
    }
    return r;
}

int biggest_stadium(int N, std::vector<std::vector<int>> F)
{
    return bf(N,F);
}