#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int x[n], y[n];     for (int i = 0; i < n; i++) {       cin >> x[i] >> y[i];     }     if (n == 1) {       cout << -1 << endl;     } else if (n == 2) {       if (x[0] != x[1] && y[0] != y[1]) {         int a = fabs(x[0] - x[1]), b = fabs(y[0] - y[1]);         cout << a * b << endl;       } else {         cout << -1 << endl;       }     } else if (n == 3 || n == 4) {       sort(x, x + n);       sort(y, y + n);       int a = fabs(x[0] - x[n - 1]), b = fabs(y[0] - y[n - 1]);       cout << a * b << endl;     }     return 0;   }   