#include <bits/stdc++.h>
using namespace std;

#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define fi first
#define se second

struct point {
    int x, y;
    int id;
    point() : x(0), y(0), id(-1) {}
    point(int x_, int y_, int id_) :
        x(x_), y(y_), id(id_) {}
};

int sg(int x) {
    if(x < 0) {
        return -1;
    }
    if(x > 0) {
        return 1;
    }
    return 0;
}

int direction(point a, point b, point c) {
    return sg((c.y - a.y) * (b.x - a.x) - (b.y - a.y) * (c.x - a.x));
}

bool between(point a, point b, point c) {
    return c.x >= min(a.x, b.x) && c.x <= max(a.x, b.x) && c.y >= min(a.y, b.y) && c.y <= max(a.y, b.y);
}

bool on_segment(point a, point b, point c) {
    return direction(a, b, c) == 0 && between(a, b, c);
}

bool intersect(point a, point b, point c, point d) {
    return on_segment(a, b, c) || on_segment(a, b, d) || on_segment(c, d, a) || on_segment(c, d, b)
        || (direction(a, b, c) * direction(a, b, d) == -1 && direction(c, d, a) * direction(c, d, b) == -1);
}

const int maxn = 1000;
const int inf = 1e9 + 7;
const point far = point(1, -inf, -1);
const point origin = point(0, 0, -1);

int n;
point points[1 + maxn];
unsigned int dist[1 + maxn][1 + maxn];
bool intersects[1 + maxn][1 + maxn];
int vis[1 + maxn];
unsigned int len;
int cur_comp;

void dfs(int cur) {
    vis[cur] = cur_comp;
    for(int nei = 1; nei <= n; nei++) {
        if(nei == cur || vis[nei] || dist[cur][nei] > len || intersects[cur][nei]) {
            continue;
        }
        dfs(nei);
    }
}

bool good(unsigned int cur_len) {
    len = cur_len;
    cur_comp = 0;
    for(int i = 1; i <= n; i++) {
        vis[i] = false;
    }
    for(int i = 1; i <= n; i++) {
        if(!vis[i]) {
            cur_comp++;
            dfs(i);
        }
    }
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            if(i != j && vis[i] == vis[j] && dist[i][j] <= len && intersects[i][j]) {
                return true;
            }
        }
    }
    return false;
}

void solve() {
    cin >> n;
    for(int i = 1; i <= n; i++) {
        cin >> points[i].x >> points[i].y;
        points[i].id = i;
    }
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            dist[i][j] = (points[i].x - points[j].x) * (points[i].x - points[j].x)
                + (points[i].y - points[j].y) * (points[i].y - points[j].y);
            intersects[i][j] = intersect(points[i], points[j], origin, far);
        }
    }
    unsigned int l = 0, r = 8e18 + 1;
    while(l < r - 1) {
        unsigned int mid = (l + r) / 2;
        if(good(mid)) {
            r = mid;
        } else {
            l = mid;
        }
    }
    if(r == 8e18 + 1) {
        cout << "-1\n";
    } else {
        cout << r << "\n";
    }
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
}