#include <iostream>
#include <map>
#include <algorithm>
#include <cstring>
#include <string.h>
#include <time.h>
#include <stdio.h>
#include <vector>
#include <cmath>
using namespace std;
typedef long long ll;
typedef double db;
int b,max1,rez,k,m,k1,k2,k3,k4,k5,k6,i,n,j;
int a[1001][1001],dp[1001][1001];
ll gcd(ll a, ll b)
{
if (a<b) swap(a,b);
if (b==0) return a; else
return gcd(b,a%b);
}
int main()
{
char c;
freopen("INPUT.TXT","r",stdin);
freopen("OUTPUT.TXT","w",stdout);
cin>>n;
for (i=0;i<n;i++)
for (j=0;j<n;j++)
{
cin>>c;
a[i][j]=(int)c-48;
if (a[i][j]==1) dp[i][j]=1; else dp[i][j]=0;
}
int max1=1;
for (i=1;i<n;i++)
for (j=1;j<n;j++)
if (dp[i][j]>0&&dp[i-1][j-1]>0&&dp[i-1][j]>0&&dp[i][j-1]>0)
{
k1=min(min(dp[i-1][j-1],dp[i][j-1]),dp[i-1][j]);
dp[i][j]=(sqrt((db)k1)+1)*(sqrt((db)k1)+1);
if (dp[i][j]>max1) max1=dp[i][j];
}
cout<<max1<<endl;
return 0;
}