#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main () {
	int n;
	vector<int> x, y;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x[i] >> y[i];
	}
	sort (x.begin(), x.end());
	sort (y.begin(), y.end());
	int r = (x[n - 1] - x[0]) * (y[n - 1] - y[0]);
	if (r <= 0) cout << -1;
	else cout << r << endl;
	return 0;
}