#include <iostream>
#include <vector>
using namespace std;
typedef pair<long long, long long> pt;
long long d(pt a, pt b) {
return a.first*b.first+a.second*b.second;
}
pt mod(pt a,pt b, pt c) {
if(a.first<0) {a.first*=-1; a.second*=-1;}
if(b.second<0) {b.first*=-1; b.second*=-1;}
long long multb = d(b,c)/(b.first*b.first+b.second*b.second);
long long multa = d(a,c)/(a.first*a.first+a.second*a.second);
return {c.first-b.first*multb-a.first*multa,c.second-b.second*multb-a.second*multa};
}
pair<pt,pt> reduce(pt a, pt b, pt c) {
if(a==b) return {b,c};
c = mod(a,b,c);
pt p = {0,0};
if(c == p) return {a,b};
return reduce(b,c,a);
}
int main() {
int n; cin>>n;
if(n<3) {
cout<<-1<<endl;
return 0;
}
pt prev;
cin>>prev.first>>prev.second;
vector<pt> t(n-1);
for (int i = 0; i < n-1; ++i) {
int x,y; cin>>x>>y;
t[i] = {prev.first-x,prev.second-y};
}
pair<pt,pt> res = {t[0],t[1]};
for (int i = 0; i < n-3; ++i) {
res = reduce(res.first,res.second,t[i+2]);
}
pt p = {0,0};
if(res.first==res.second || res.first==p || res.second==p) {
cout<<-1<<endl;
return 0;
}else {
cout<<abs(res.first.first*res.second.second-res.first.second*res.second.first)<<endl;
return 0;
}
}
