#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, w = 0, h = 0;
  int x[4], y[4];
  cin >> n;
  for (i = 0; i < n; i++) cin >> x[i] >> y[i];
  if (i == 1)
    cout << -1;
  else if (i == 2) {
    w = abs(x[0] - x[1]);
    h = abs(y[0] - y[1]);
    if (w * h == 0)
      cout << -1;
    else
      cout << w * h;
  } else {
    for (i = 0; i < n; i++) {
      for (int j = i + 1; j < n; j++) {
        w = abs(x[i] - x[j]);
        h = abs(y[i] - y[j]);
        if (w * h != 0) {
          cout << w * h;
          break;
        }
      }
      if (w * h != 0) break;
    }
  }
}
