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