#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N;
cin >> N;
if (N <= 2) {
cout << -1;
return 0;
}
int x[N+1], y[N+1];
for (int i = 1; i <= N; i++) cin >> x[i] >> y[i];
pair<int, int> minpos = {x[1], y[1]};
for (int i = 2; i <= N; i++) minpos = min(minpos, make_pair(x[i], y[i]));
ll sx = 0, sy = 0;
for (int i = 1; i <= N; i++) {
ll dx = abs(minpos.first - x[i]);
ll dy = abs(minpos.second - y[i]);
if (dx != 0 && dy == 0) sx = gcd(sx, dx);
if (dy != 0 && dx == 0) sy = gcd(sy, dy);
}
cout << (sx*sy == 0 ? -1 : sx*sy);
return 0;
}
/*
3
1 1
1 3
3 2
5
0 0
1 0
-1 0
0 1
0 -1
1
1 -1
*/
