#include<iostream>
using namespace std;
#include<vector>
long long invmod(long long a,long long m)
{
	long long s=a%m,t=m,sx=1,sy=0,tx=0,ty=1;
	while(s%t!=0)
	{
		long long f=s/t;
		long long u=s-t*f,ux=sx-tx*f,uy=sy-ty*f;
		s=t,sx=tx,sy=ty;
		t=u,tx=ux,ty=uy;
	}
	if(tx<0)tx+=m;
	return tx;
}
long long garner(const vector<long long>&x,const vector<long long>&m,const int mod=0)//*=x mod m
{
	vector<long long>v(x.size());
	v[0]=x[0];
	for(int i=1;i<x.size();i++)
	{
		long long X=(x[i]-x[0])%m[i];
		long long M=1;
		for(int j=0;j<i-1;j++)
		{
			(M*=m[j])%=m[i];
			(X-=v[j+1]*M)%=m[i];
		}
		(M*=m[i-1])%=m[i];
		if(X<0)X+=m[i];
		v[i]=X*invmod(M,m[i])%m[i];
	}
	long long ret=v[0],p=1;
	if(mod==0)
	{
		for(int i=1;i<x.size();i++)
		{
			p*=m[i-1];
			ret+=p*v[i];
		}
	}
	else
	{
		ret%=mod;
		for(int i=1;i<x.size();i++)
		{
			(p*=m[i-1])%=mod;
			(ret+=p*v[i])%=mod;
		}
	}
	return ret;
}
#include<map>
map<int,int>M,S;
map<int,bool>isp;
main()
{
	int N;cin>>N;
	for(int i=0;i<N;i++)
	{
		int a,b;cin>>a>>b;
		for(int j=2;j*j<=b;j++)
		{
			if(b%j==0)
			{
				int p=1;
				while(b%j==0)
				{
					p*=j;
					b/=j;
				}
				isp[j]=true;
				S[j]=max(S[j],p);
				if(j!=p)S[p]=j;
				if(M.find(p)!=M.end())
				{
					if(M[p]!=a%p)
					{
						cout<<-1<<endl;
						return 0;
					}
				}
				else
				{
					M[p]=a%p;
				}
			}
		}
		if(b>1)
		{
			S[b]=max(S[b],b);
			isp[b]=true;
			if(M.find(b)!=M.end())
			{
				if(M[b]!=a%b)
				{
					cout<<-1<<endl;
					return 0;
				}
			}
			else M[b]=a%b;
		}
	}
	vector<long long>A,B;
	for(map<int,int>::iterator it=M.begin();it!=M.end();it++)
	{
		int b=it->second,a=it->first;
		int t=a;
		if(isp.find(t)==isp.end())t=S[t];
		t=S[t];
		if(M[t]%a!=b)
		{
			cout<<-1<<endl;
			return 0;
		}
	}
	for(map<int,bool>::iterator it=isp.begin();it!=isp.end();it++)
	{
		int a=S[it->first];
		int b=M[a];
		A.push_back(b);
		B.push_back(a);
	}
	long long ans=garner(A,B,1e9+7);
	if(ans==0)
	{
		ans=1;
		for(int i=0;i<B.size();i++)(ans*=B[i])%=(int)(1e9+7);
	}
	cout<<ans<<endl;
}