#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int nx=1e5+5;
ll n, x[nx], y[nx], gx, gy;
vector<ll> vx, vy;
struct myvector
{
ll x, y;
myvector(ll x, ll y): x(x), y(y){}
};
ll cross(myvector a, myvector b)
{
return a.x*b.y-a.y*b.x;
}
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n;
for (int i=1; i<=n; i++) cin>>x[i]>>y[i], vx.push_back(x[i]), vy.push_back(y[i]);
sort(vx.begin(), vx.end());
vx.erase(unique(vx.begin(), vx.end()), vx.end());
sort(vy.begin(), vy.end());
vy.erase(unique(vy.begin(), vy.end()), vy.end());
if (vx.size()==1||vy.size()==1) return cout<<-1, 0;
for (int i=1; i<vx.size(); i++) gx=__gcd(gx, vx[i]-vx[i-1]);
for (int i=1; i<vy.size(); i++) gy=__gcd(gy, vy[i]-vy[i-1]);
cout<<gx*gy;
}
