#include <bits/stdc++.h>
using namespace std;
void print_ans(int x1, int y1, int x2, int y2) {
  long long int ans;
  ans = (x1 - x2) * (y1 - y2);
  if (ans < 0) ans = -ans;
  cout << ans;
  return;
}
int main() {
  int n, x[4], y[4], i;
  cin >> n;
  if (n < 2)
    cout << "-1";
  else {
    for (i = 0; i < n; i++) cin >> x[i] >> y[i];
    if (n == 2) {
      if (x[0] == x[1] || y[0] == y[1])
        cout << "-1";
      else
        print_ans(x[0], y[0], x[1], y[1]);
    } else {
      if (x[0] != x[1] && y[0] != y[1])
        print_ans(x[0], y[0], x[1], y[1]);
      else if (x[1] != x[2] && y[1] != y[2])
        print_ans(x[1], y[1], x[2], y[2]);
      else
        print_ans(x[0], y[0], x[2], y[2]);
    }
  }
  return 0;
}
