#include <bits/stdc++.h>
const int N = (int)1e6 + 123;
const long long linf = (long long)1e18 + 123;
const int inf = (int)1e9 + 123;
const double eps = 1e-6;
using namespace std;
void boost() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
}
long long a[111], b[111], mx, n;
int main() {
  boost();
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i] >> b[i];
  if (n == 1) {
    cout << -1;
    exit(0);
  }
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      mx = max(mx, abs(a[i] - a[j]) * abs(b[i] - b[j]));
    }
  }
  if (mx == 0)
    cout << -1;
  else
    cout << mx;
  return 0;
}
