// what is matter? never mind. 
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,sse4,popcnt,abm,mmx,avx,avx2")
#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
//#define int long long
#define ull unsigned long long
using namespace std;
inline int read()
{
	char c=getchar();int x=0;bool f=0;
	for(;!isdigit(c);c=getchar())f^=!(c^45);
	for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
	if(f)x=-x;return x;
}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;

#define N 2005
#define inf 0x3f3f3f3f

int n,a[N][N];
int up[N][N],dw[N][N];

int f[N][N],mn[N][N],mn2[N][N];
int biggest_stadium(int nn,vector<vector<int>>MP){
	n=nn; For(i,1,n)For(j,1,n)a[i][j]=MP[i-1][j-1];
	For(i,1,n)For(j,1,n)up[i][j]=(a[i][j]?0:up[i-1][j]+1);
	Rep(i,n,1)For(j,1,n)dw[i][j]=(a[i][j]?0:dw[i+1][j]+1);
//	For(i,1,n)For(j,1,n)cout<<up[i][j]<<" \n"[j==n];
	int res=0;
	For(i,1,n){
		int l=1,r;
		for(;l<=n;l=r+1){
			r=l;
			while(r<n && a[i][r+1]==a[i][l])++r;
			if(a[i][l])continue;
			For(j,l,r){
				mn[j][j]=dw[i][j];
				mn2[j][j]=up[i][j];
				For(k,j+1,r) mn[j][k]=min(mn[j][k-1],dw[i][k]),
							 mn2[j][k]=min(mn2[j][k-1],up[i][k]);
			}
			For(j,l,r)For(k,l,r)f[j][k]=-inf;
			f[l][r]=(mn[l][r]+mn2[l][r]-1)*(r-l+1);
			Rep(len,r-l+1,2){
				for(int j=l,k=l+len-1;k<=r;++j,++k){
					int now=mn[j][k]+mn2[j][k];
					f[j+1][k]=max(f[j+1][k],f[j][k]+(mn[j+1][k]+mn2[j+1][k]-now)*(len-1));
					f[j][k-1]=max(f[j][k-1],f[j][k]+(mn[j][k-1]+mn2[j][k-1]-now)*(len-1));
				}
			}
			For(i,l,r) res=max(res,f[i][i]);
		}
	}
	return res;
}