#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  if (n <= 1) {
    cout << "-1";
    return 0;
  }
  int p[4][2];
  for (int i = 0; i < n; i++) {
    cin >> p[i][0];
    cin >> p[i][1];
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      int pov = (int)(abs(p[i][0] - p[j][0]) * abs(p[i][1] - p[j][1]));
      if (pov > 0) {
        cout << pov;
        return 0;
      }
    }
  }
  cout << "-1";
  return 0;
}
