#include <bits/stdc++.h>
using namespace std;
using ll = __int128; using pii = pair<ll,ll>;
const ll INF = 1e18;
ll gcd2(ll a, ll b) {
if (a==0) {
return b;
}
if (b==0) {
return a;
}
return gcd(labs(a),labs(b));
}
ll cpr(pii p1, pii p2) {
return (p1.first*p2.second-p1.second*p2.first);
}
pii fix(pii p1, pii p2) { //assuming cpr = 0, adjust both
if (p1.first==0 && p1.second==0) {
return p2;
}
if (p2.first==0 && p2.second==0) {
return p1;
}
if (p1.first==0 && p2.first==0) {
return {0LL,gcd2(p1.second,p2.second)};
}
if (p1.second==0 && p2.second==0) {
return {gcd2(p1.first,p2.first),0LL};
}
ll a = gcd2(p1.first,p2.first);
return {a,(p1.second*a)/p1.first};
}
pair<pii,pii> tw(pair<pii,pii> A0) {
return {A0.second,A0.first};
}
inline ll amod(ll a, ll MOD) {
return (a+MOD*(2-a/MOD))%MOD;
}
pair<pii,pii> REDUCE(pair<pii,pii> A0) {
ll MOD = labs(cpr(A0.first,A0.second));
return {(pii){amod(A0.first.first,MOD),amod(A0.first.second,MOD)},(pii){amod(A0.second.first,MOD),amod(A0.second.second,MOD)}};
}
ll inv(ll x, ll MOD) {
assert(MOD>0);
array<ll,3> a = {(x+MOD*(2-x/MOD))%MOD,1,0};
array<ll,3> b = {MOD,0,1};
while (b[0]!=1) {
if (a[0]>b[0]) {
swap(a,b);
} else {
ll k = b[0]/a[0];
for (ll i=0;i<3;i++) {
b[i]-=k*a[i];
}
}
}
ll fv = b[1];
return (fv+MOD*(2-fv/MOD))%MOD;
}
pair<pii,pii> fz(pair<pii,pii> A0, pii pf) {
pii p0 = A0.first; pii p1 = A0.second;
//cout << "input: p0/p1= "<<p0.first<<","<<p0.second<<"; "<<p1.first<<","<<p1.second<<"\n";
//cout << "input: pf= "<<pf.first<<","<<pf.second<<"\n";
ll L0 = cpr(p0,p1);
ll L1 = cpr(p0,pf);
if (L1==0) {
//cout << "fix: "<<fix(p0,pf).first<<","<<fix(p0,pf).second<<"\n";
return {fix(p0,pf),p1};
}
if (gcd2(L0,L1)==labs(L0)) {
return A0;
}
ll LG = gcd2(L0,L1);
L0 = L0/LG; L1 = L1/LG;
if (L1<0) {
L0 = -L0; L1 = -L1;
}
//cout << "L0,L1="<<L0<<","<<L1<<"\n";
ll A = inv(L0,L1);
ll B = (1-A*L0)/L1;
//cout << "A,B="<<A<<","<<B<<"\n";
assert((1-A*L0)%L1==0);
pii PEND = {p1.first*A+pf.first*B,p1.second*A+pf.second*B};
//cout << "new after p0: "<<PEND.first<<","<<PEND.second<<"\n";
return REDUCE({p0,PEND});
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
long long N; cin >> N;
if (N<=2) {
cout << "-1\n"; exit(0);
}
long long x1,y1; cin >> x1 >> y1;
vector<pii> v0;
for (ll i=0;i<(N-1);i++) {
long long x2,y2; cin >> x2 >> y2;
v0.push_back({x2-x1,y2-y1});
}
pii pa = v0[0]; pii pb = {-INF,-INF};
bool tkb = false;
for (ll i=1;i<(N-1);i++) {
pii pc = v0[i];
if (!tkb) {
if (cpr(pa,pc)==0) {
pa = fix(pa,pc);
} else {
tkb = 1; pb = pc;
}
} else {
if (cpr(pa,pc)==0) {
pa = fix(pa,pc);
} else if (cpr(pb,pc)==0) {
pb = fix(pb,pc);
} else {
pair<pii,pii> MEM = {pa,pb};
while(1) {
ll ans0 = labs(cpr(MEM.first,MEM.second));
MEM = fz(MEM,pa);
MEM = tw(MEM);
MEM = fz(MEM,pa);
MEM = fz(MEM,pb);
MEM = tw(MEM);
MEM = fz(MEM,pb);
MEM = fz(MEM,pc);
MEM = tw(MEM);
MEM = fz(MEM,pc);
ll ans1 = labs(cpr(MEM.first,MEM.second));
assert(ans1<=ans0);
assert(ans0%ans1==0);
if (ans1==ans0) {
break;
}
}
pa = MEM.first; pb = MEM.second;
}
}
}
if (!tkb) {
cout << "-1\n"; exit(0);
}
cout << (long long) labs(cpr(pa,pb)) <<"\n";
}
