#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int nx=1e5+5;
ll n, x[nx], y[nx];
struct myvector
{
ll x, y;
myvector(ll x=0, ll y=0): x(x), y(y){}
bool operator< (const myvector &o) const {return 1;}
};
vector<myvector> v;
ll cross(myvector a, myvector b)
{
return a.x*b.y-a.y*b.x;
}
myvector merge(myvector a, myvector b)
{
return myvector(__gcd(a.x, b.x), __gcd(a.y, b.y));
}
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n;
for (int i=1; i<=n; i++) cin>>x[i]>>y[i];
for (int i=2; i<=n; i++) v.push_back(myvector(x[i]-x[1], y[i]-y[1]));
while (v.size()>=3)
{
auto a=v.back();
v.pop_back();
auto b=v.back();
v.pop_back();
auto c=v.back();
v.pop_back();
if (cross(a, b)==0) v.push_back(merge(a, b)), v.push_back(c);
else if (cross(b, c)==0) v.push_back(merge(b, c)), v.push_back(a);
else if (cross(a, c)==0) v.push_back(merge(a, c)), v.push_back(b);
else
{
auto mn=min({abs(cross(a, b)), abs(cross(a, c)), abs(cross(b, c))});
if (abs(cross(a, b))==mn)
{
ll k=(b.y*c.x-b.x*c.y)/(b.y*a.x-b.x*a.y);
ll l=(a.y*c.x-a.x*c.y)/(a.y*b.x-a.x*b.y);
c.x-=k*a.x+l*b.x;
c.y-=k*a.y+l*b.y;
}
else if (abs(cross(a, c))==mn)
{
swap(b, c);
ll k=(b.y*c.x-b.x*c.y)/(b.y*a.x-b.x*a.y);
ll l=(a.y*c.x-a.x*c.y)/(a.y*b.x-a.x*b.y);
c.x-=k*a.x+l*b.x;
c.y-=k*a.y+l*b.y;
}
else
{
swap(a, c);
ll k=(b.y*c.x-b.x*c.y)/(b.y*a.x-b.x*a.y);
ll l=(a.y*c.x-a.x*c.y)/(a.y*b.x-a.x*b.y);
c.x-=k*a.x+l*b.x;
c.y-=k*a.y+l*b.y;
}
v.push_back(a);
v.push_back(b);
v.push_back(c);
}
}
if (v.size()<=1||(v.size()==2&&cross(v[0], v[1])==0)) cout<<-1;
else cout<<abs(cross(v[0], v[1]));
}
/*
3
1 2
4 1
0 0
*/
