#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <ll,ll> pll;
typedef pair <int,int> pii;
typedef pair <int,pii> piii;
#define forr(_a,_b,_c) for(int _a = (_b); _a <= int (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> int (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < int (_c); ++_a)
#define st first
#define nd second
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"
template<class X, class Y>
bool minz(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} return false;
}
template<class X, class Y>
bool maxz(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} return false;
}
const int N = 5e5 + 5;
const ll oo = (ll) 1e16;
const ll mod = 1e9 + 7; // 998244353;
int n, xx, yy, ox, oy, lx = 1, ly = 1, gx = -1, gy = -1;
vector <pii> vv;
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef kaguya
freopen(file".inp", "r", stdin); freopen(file".out", "w", stdout);
#endif
cin >> n;
forr (i, 1, n){
cin >> xx >> yy;
vv.pb({xx, yy});
if (i == 1) {
ox = xx;
oy = yy;
}
else {
if (ox != xx) {
lx = 0;
}
if (oy != yy) {
ly = 0;
}
}
}
if (n <= 2 || (ly || lx)) {
cout << -1;
return 0;
}
forf (i, 0, n - 1){
if (abs(vv[i].st - vv[i + 1].st) != 0)
gx = __gcd(gx, abs(vv[i].st - vv[i + 1].st));
if (abs(vv[i].nd - vv[i + 1].nd) != 0)
gy = __gcd(gy, abs(vv[i].nd - vv[i + 1].nd));
}
cout << gx * gy << "\n";
return 0;
}
/*
*/
