#include <bits/stdc++.h>
using namespace std;
int fun(int x1, int y1, int x2, int y2) {
  int dx = abs(x1 - x2);
  int dy = abs(y1 - y2);
  if (dx * dy != 0)
    return dx * dy;
  else
    return -1;
}
int main() {
  int n;
  cin >> n;
  int x[4];
  int y[4];
  for (int i = 0; i < n; ++i) {
    cin >> x[i] >> y[i];
  }
  if (n == 1)
    cout << -1 << endl;
  else {
    int ans = -1;
    for (int i = 0; i < n; ++i) {
      for (int j = i + 1; j < n; ++j) {
        ans = max(ans, fun(x[i], y[i], x[j], y[j]));
      }
    }
    cout << ans << endl;
  }
  return 0;
}
