#include <bits/stdc++.h>
using namespace std;
int x[4], y[4];
int main() {
  int n, ans = -1;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> x[i] >> y[i];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      if (x[i] != x[j] && y[i] != y[j])
        ans = abs(x[i] - x[j]) * abs(y[i] - y[j]);
  cout << ans << endl;
}
