#include <bits/stdc++.h>

using namespace std;
const int c=2005;
long long n, x[c], y[c];
vector<pair<long long, pair<int, int> > > sz;
int ki[c];
int holvan(int a) {
    return (ki[a] ? ki[a]=holvan(ki[a]) : a);
}
void unio(int a, int b) {
    a=holvan(a), b=holvan(b);
    if (a!=b) {
        ki[a]=b;
    }
}
int irany(int a, int b, int c) {
    long long ert=(x[b]-x[a])*(y[c]-y[a])-(x[c]-x[a])*(y[b]-y[a]);
    if (ert>0) return 1;
    if (ert<0) return -1;
    if (ert==0) return 0;
}
bool kozott(int a, int b, int c) {
    if (x[b]>max(x[a], x[c]) || x[b]<min(x[a], x[c]) || y[b]>max(y[a], y[c]) || y[b]<min(y[a], y[c])) {
        return false;
    }
    return true;
}
int main()
{
    cin >> n;
    for (int i=1; i<=n; i++) {
        cin >> x[i] >> y[i];
    }
    for (int i=1; i<=n; i++) {
        for (int j=i+1; j<=n; j++) {
            if (x[j]<x[i]) {
                swap(x[i], x[j]);
                swap(y[i], y[j]);
            }
        }
    }
    for (int i=1; i<=n; i++) {
        for (int j=i+1; j<=n; j++) {
            long long dist=(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]);
            sz.push_back({dist, {i, j}});
        }
    }
    sort(sz.begin(), sz.end());
    for (auto p:sz) {
        long long ert=p.first, a=p.second.first, b=p.second.second;
        int val=0, dir=irany(a, b, 0);
        if (dir==0 && kozott(a, 0, b)) continue;
        if (x[a]<0 && x[b]>=0 && dir==1) {
            val=1;
        }
        if (!val) {
            unio(a, b);
            unio(a+n, b+n);
        } else {
            unio(a, b+n);
            unio(a+n, b);
        }
        if (holvan(a)==holvan(a+n)) {
            cout << ert << "\n";
            return 0;
        }
    }
    cout << -1 << "\n";
    return 0;
}