#include <bits/stdc++.h>
using namespace std;

#define int long long

const int N=1e5+5;

int gcd(int x,int y)
{
	if(x>y)
		swap(x,y);

	if(x==0)
		return y;

	return gcd(y%x,x);
}

int x[N],y[N],val[N];
map <pair <int,int> ,bool> have;

pair <int,int> topair(int x,int y)
{
	if(x==0)
		return make_pair(0x3f3f3f3f,0);

	if(y==0)
		return make_pair(0,0);

	int GCD=gcd(abs(x),abs(y));
	x /= GCD, y /= GCD;
	if(x<0)
		x=-x, y=-y;
	return make_pair(x,y);
}

signed main()
{
	int n;
	cin >> n;
	if(n<=2)
	{
		printf("-1\n");
		return 0;
	}

	for(int i=1;i<=n;i++)
		scanf("%lld %lld",&x[i],&y[i]);

	for(int i=1;i<n;i++)
		x[i] -= x[n], y[i] -= y[n];
	n--;

	for(int i=1;i<=n;i++)
		have[topair(x[i],y[i])]=true;

	if(have.size()==1)
	{
		printf("-1\n");
		return 0;
	}

	int GCDx=0;
	for(int i=1;i<=n;i++)
		GCDx=gcd(GCDx,abs(x[i]));

	int GCDy=0;
	for(int i=1;i<=n;i++)
		GCDy=gcd(GCDy,abs(y[i]));

	int ans=GCDx*GCDy;
	for(int i=1;i<=n;i++)
		x[i] /= GCDx, y[i] /= GCDy;

	int GCD=gcd(abs(x[n]),abs(y[n]));
	for(int i=1;i<n;i++)
		val[i]=x[n]/GCD*y[i]-y[n]/GCD*x[i];

	int GCDall=0;
	for(int i=1;i<n;i++)
		GCDall=gcd(GCDall,abs(val[i]));

	printf("%lld\n",GCDall*ans);
	return 0;
}