#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;
}
