//
//
//  Codeforces: ganariya
//  AtCoder: ganariya2525
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//include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <unordered_map>
#include <climits>
#include <set>
#include <unordered_set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <queue>
#include <random>
#include <complex>
#include <regex>
#include <locale>
#include <random>
#include <type_traits>

using namespace std;

#define SHOW_VECTOR(v) {std::cerr << #v << "\t:";for(const auto& xxx : v){std::cerr << xxx << " ";}std::cerr << "\n";}
#define SHOW_MAP(v){std::cerr << #v << endl; for(const auto& xxx: v){std::cerr << xxx.first << " " << xxx.second << "\n";}}

using LL = long long;

//~~~~~~~~~~~~~~~~~~~~~_(＾～＾ ｣ ∠)_~~~~~~~~~~~~~~~~~~~~~

typedef complex<int> P;

P make_P(pair<int, int> pr) {
    return P(pr.first, pr.second);
}

pair<int, int> make_pr(P p) {
    return make_pair(p.real(), p.imag());
}

int main() {

    while (true) {

        int n;
        cin >> n;

        if (n == 0) break;

        vector<P> points(n);
        map<pair<int, int>, bool> m;
        for (int i = 0; i < n; i++) {
            int x, y;
            cin >> x >> y;
            points[i] = P(x, y);
            m[make_pair(x, y)] = true;
        }

        sort(points.begin(), points.end(), [](const auto &x, const auto &y) {
                 return x.real() < y.real();
             }
        );

        int ans = 0;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                auto p1 = points[i];
                auto p2 = points[j];
                auto v = p2 - p1;
                auto plus = v * P(0, 1);
                auto minus = v * P(0, -1);
                {
                    auto p3 = p1 + plus;
                    auto p4 = p2 + plus;
                    if (m.count(make_pr(p3)) && m.count((make_pr(p4)))) {
                        ans = max(ans, v.real() * v.real() + v.imag() * v.imag());
                    }
                }
                {
                    auto p3 = p1 + minus;
                    auto p4 = p2 + minus;
                    if (m.count(make_pr(p3)) && m.count((make_pr(p4)))) {
                        ans = max(ans, v.real() * v.real() + v.imag() * v.imag());
                    }
                }
            }
        }

        cout << ans << endl;
    }


    return 0;
}






































Measured memory_bytes: 3196