#include<bits/stdc++.h>
// #define int long long
#define reg register
inline int read(){
	int k=1,x=0;char ch=getchar();
	while (ch<'0'||ch>'9') {if (ch=='-') k=-1; ch=getchar();}
	while (ch>='0'&&ch<='9') x=(x<<3)+(x<<1)+ch-48,ch=getchar();
	return k*x;
}
const int N=2e5+10,V=400;
int n,a[N],b[N];
struct Node{int x,y;}p[N];
inline int cabs(reg int x){return x<0?-x:x;}
signed main(){
	n=read();
	for (reg int i=1;i<=n;i++) p[i].x=read(),p[i].y=read();
	reg int ga=0,gb=0;
	for (reg int i=1;i<n;i++) a[i]=cabs(p[i].x-p[i+1].x),b[i]=cabs(p[i].y-p[i+1].y);
	std::sort(a+1,a+n+1),std::sort(b+1,b+n+1);
	reg int ma=std::unique(a+1,a+n+1)-a-1,mb=std::unique(b+1,b+n+1)-b-1;
	if (ma<2||mb<2) return puts("-1"),0;
	for (reg int i=1;i<ma;i++) ga=std::__gcd(ga,a[i]);
	for (reg int i=1;i<mb;i++) gb=std::__gcd(gb,b[i]);
	printf("%lld\n",1ll*ga*gb);
	return 0;
}