#line 1 "a.cpp"
#define PROBLEM "https://yukicoder.me/problems/no/186"
#include<iostream>
using namespace std;
#line 1 "/home/kotatsugame/library/math/linear_congruence.cpp"
//require extgcd
#include<vector>
#line 1 "/home/kotatsugame/library/math/extgcd.cpp"
template<typename T>
T extgcd(T a,T b,T&x,T&y)
{
	if(b==0)
	{
		x=1;
		y=0;
		return a;
	}
	T q=a/b;
	T g=extgcd(b,a-q*b,y,x);
	y-=q*x;
	return g;
}
#line 4 "/home/kotatsugame/library/math/linear_congruence.cpp"
pair<long long,long long>linear_congruence(const vector<int>&A,const vector<int>&B,const vector<int>&M)
//find Ax=B mod M. NA=>(0,-1)
{
	long long x=0,m=1;
	for(int i=0;i<A.size();i++)
	{
		long long a=m*A[i],b=B[i]-x*A[i],u,v;
		long long d=extgcd(a,(long long)M[i],u,v);
		if(b%d!=0)return make_pair(0LL,-1LL);
		long long t=b/d*u%(M[i]/d);
		x+=m*t;
		m*=M[i]/d;
	}
	x%=m;
	if(x<0)x+=m;
	return make_pair(x,m);
}
#line 5 "a.cpp"
int main()
{
	vector<int>r(3),m(3);
	for(int i=0;i<3;i++)cin>>r[i]>>m[i];
	pair<long,long>p=linear_congruence({1,1,1},r,m);
	if(p.second==-1)cout<<-1<<endl;
	else cout<<(p.first==0?p.second:p.first)<<endl;
}