#include <bits/stdc++.h>
#define xy pair<ll, ll>

using ll = long long;
using namespace std;

const int MAXN = 1001;
const ll INF = 1e8;

struct Edge {
    ll dist; int u, v;
    bool cross;
};

int dsu[2*MAXN];
vector<xy> points;
vector<Edge> edges;

int find(int u) {
    return dsu[u]==u?u:dsu[u]=find(dsu[u]);
}

void unio(int u, int v) {
    u = find(u); v = find(v);
    if (u != v) {
        dsu[u] = v;
    }
}

bool cross(ll x1, ll y1, ll x2, ll y2) {
    return x1*y2 - x2*y1 < 0;
}

int main() {
    cin.sync_with_stdio(0); cin.tie(0);
    int n; cin >> n;
    iota(dsu, dsu+2*MAXN, 0);
    for (int i = 1; i <= n; i++) {
        ll x, y; cin >> x >> y;
        points.emplace_back(x, y);
    }
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            Edge e;
            e.u = i; e.v = j;
            auto [x1, y1] = points[i];
            auto [x2, y2] = points[j];
            ll dx = x1 - x2;
            ll dy = y1 - y2;
            e.dist = dx*dx + dy*dy;
            if (y1 > y2) {
                swap(x1, x2);
                swap(y1, y2);
            }
            if (y1 <= 0 && y2 > 0 && cross(-x1, -y1, x2-x1, y2-y1)) e.cross = true;
            else e.cross = false;
            edges.emplace_back(e);
        }
    }
    sort(edges.begin(), edges.end(), [](Edge a, Edge b){
        return a.dist < b.dist;
    });
    for (Edge e : edges) {
        if (e.cross) {
            unio(e.u, e.v+n);
            unio(e.u+n, e.v);
        } else {
            unio(e.u, e.v);
            unio(e.u+n, e.v+n);
        }
        if (find(e.u) == find(e.u+n) || find(e.v) == find(e.v+n)) {
            cout << e.dist << "\n";
            return 0;
        }
    }
    cout << "-1\n";
    return 0;
}