#include "soccer.h"
#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;using LL=__int128;
const int N=2e3+5,M=5e5+5,K=(1<<25)+5,mod=998244353,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(time(0));
int n,A[N][N],B[N];
int L[N],R[N];
int CK(){
	int i,j;
	for(i=1;i<=n;i++){
		int flag=0;for(j=1;j<=n;j++) if(!A[i][j]) flag=1;
		if(!flag) continue;
		L[i]=1;while(A[i][L[i]]) L[i]++;
		R[i]=L[i];while(R[i]<n&&!A[i][R[i]+1]) R[i]++;
		for(j=R[i]+1;j<=n;j++) if(!A[i][j]) return 0;
	}
	iota(B+1,B+n+1,1);
	sort(B+1,B+n+1,[](int x,int y){return R[x]-L[x]>R[y]-L[y];});
	int l=B[1],r=B[1];
	for(i=2;i<=n;i++) if(L[B[i]]){
		if(B[i]!=l-1&&B[i]!=r+1) return 0;
		if(!(L[B[i]]>=L[B[i-1]]&&R[B[i]]<=R[B[i-1]])) return 0;
		l=min(l,B[i]);r=max(r,B[i]);
	}
	int tot=0;for(i=1;i<=n;i++) tot+=R[i]-L[i]+1;
	return tot;
}
int biggest_stadium(int nn, std::vector<std::vector<int>> F){
	n=nn;int i,j;
	for(i=1;i<=n;i++){
		for(j=1;j<=n;j++) A[i][j]=F[i-1][j-1];
	}
	if(n>=1) return CK();
	return 0;
}