#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int mod = 1e9 + 7;


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    int maxi = 0;
    vector<vector<char>> a(n, vector<char>(n));
    vector<vector<int>> dp(n, vector<int>(n));
    for(int i = 0; i < n; ++i){
        string s;
        cin >> s;
        for(int j = 0; j < n; ++j){
            a[i][j] = s[j];
        }
    }
    if(a[0][0] == '0')
        dp[0][0] = 0;
    else
        dp[0][0] = 1;
    maxi = max(dp[0][0], maxi);
    for(int i = 0; i < n; ++i){
        if(a[i][0] == '1')
            dp[i][0] = 1;
        maxi = max(dp[i][0], maxi);
    }
    for(int i = 0; i < n; ++i){
        if(a[0][i] == '1')
            dp[0][i] = 1;
        maxi = max(dp[0][i], maxi);
    }
    for(int i = 1; i < n; ++i){
        for(int j = 1; j < n; ++j){
            if(a[i][j] == '0')
                continue;
            else{
                dp[i][j] = min(dp[i - 1][j - 1], min(dp[i - 1][j], dp[i][j - 1])) + 1;
            }
            maxi = max(dp[i][j], maxi);
        }
    }
    cout << 1LL * maxi * maxi << endl;
}