#include <bits/stdc++.h>
using namespace std;
struct Point {
  int x;
  int y;
};
int main() {
  int n;
  cin >> n;
  Point P[n];
  for (int i = 0; i < n; i++) {
    cin >> P[i].x >> P[i].y;
  }
  int val;
  if (n < 2)
    val = -1;
  else if (n == 2) {
    if (P[0].x != P[1].x && P[0].y != P[1].y)
      val = abs(P[0].x - P[1].x) * abs(P[0].y - P[1].y);
    else
      val = -1;
  } else {
    int alt, larg;
    if ((P[0].x - P[1].x) != 0)
      alt = P[0].x - P[1].x;
    else {
      alt = P[0].x - P[2].x;
    }
    if ((P[0].y - P[1].y) != 0)
      larg = P[0].y - P[1].y;
    else {
      larg = P[0].y - P[2].y;
    }
    val = abs(alt * larg);
  }
  cout << val << endl;
}
