#include <bits/stdc++.h>
using namespace std;
int xcoord[4], ycoord[4];
int area(int a, int b) {
  return abs(xcoord[a] - xcoord[b]) * abs(ycoord[a] - ycoord[b]);
}
int main() {
  int verticec;
  cin >> verticec;
  for (int i = 0; i < verticec; i++) {
    cin >> xcoord[i] >> ycoord[i];
  }
  if (verticec == 1) {
    cout << -1 << endl;
  } else if (verticec == 2) {
    if (xcoord[0] == xcoord[1] || ycoord[0] == ycoord[1]) {
      cout << -1 << endl;
    } else {
      cout << area(0, 1) << endl;
    }
  } else if (verticec == 3) {
    if (area(0, 1))
      cout << area(0, 1) << endl;
    else if (area(0, 2))
      cout << area(0, 2) << endl;
    else
      cout << area(1, 2) << endl;
  } else {
    if (area(0, 1))
      cout << area(0, 1) << endl;
    else if (area(0, 2))
      cout << area(0, 2) << endl;
    else if (area(0, 3))
      cout << area(0, 3) << endl;
    else if (area(1, 2))
      cout << area(1, 2) << endl;
    else if (area(1, 3))
      cout << area(1, 3) << endl;
    else
      cout << area(2, 3) << endl;
  }
}
