#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ld long double
template<typename T1,typename T2>void chmn(T1 &x,const T2 &y){x=x<y?x:y;}
template<typename T1,typename T2>void chmx(T1 &x,const T2 &y){x=x>y?x:y;}
const int N=2050;
int n,a[N][N],dp[N][N],L[N][N],R[N][N],U[N][N];
vector<pair<int,int>>ev[N];
int biggest_stadium(int n1,vector<vector<int>> F){
n=n1;
for(int i=0;i<=n+1;i++)for(int j=0;j<=n+1;j++)a[i][j]=1;
for(int i=0;i<n;i++)for(int j=0;j<n;j++)a[i+1][j+1]=F[i][j];
for(int i=1;i<=n;i++){
L[i][0]=0;
for(int j=1;j<=n;j++){
if(a[i][j]==0)L[i][j]=L[i][j-1];
else L[i][j]=j;
}
R[i][n+1]=n+1;
for(int j=n;j>=1;j--){
if(a[i][j]==0)R[i][j]=R[i][j+1];
else R[i][j]=j;
}
for(int j=1;j<=n;j++){
if(a[i][j]==0){
U[i][j]=U[i-1][j];
ev[i-U[i][j]].pb({i,j});
}
else U[i][j]=i;
}
}
int res=0;
for(int d=1;d<=n;d++){
for(auto [i,j]:ev[d]){
if(a[i-1][j]==0){
chmx(L[i][j],L[i-1][j]);
chmn(R[i][j],R[i-1][j]);
}
chmx(dp[i][j],dp[i-1][j]+R[i][j]-L[i][j]-1);
chmx(dp[i][j],dp[i][L[i][j]]+(U[i][L[i][j]]-U[i][j])*(R[i][j]-L[i][j]-1));
chmx(dp[i][j],dp[i][R[i][j]]+(U[i][R[i][j]]-U[i][j])*(R[i][j]-L[i][j]-1));
chmx(res,dp[i][j]);
}
}
return res;
}
