using System;
using System.Collections;
using System.Collections.Generic;
 
class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		HashSet<long>[] H=new HashSet<long>[3];
		
		long lcm=Y[0]*Y[1]/gcd(Y[0],Y[1]);
		for(int i=0;i<3;i++)H[i]=new HashSet<long>();
		for(int i=0;i<2;i++){
			for(long x=X[i];x<lcm;x+=Y[i])H[i].Add(x);
		}
		long tmp=-1;
		foreach(var l in H[0]){
			if(H[1].Contains(l)){
				tmp=l;
			}
		}
		
		if(tmp==-1){
			Console.WriteLine(-1);
			return;
		}
		
		long lcm2=lcm*Y[2]/gcd(lcm,Y[2]);
		long ans=-1;
		for(long x=tmp;x<lcm2;x+=lcm){
			if(x%Y[2]==X[2]){ans=x;break;}
		}
		
		Console.WriteLine(ans);
		
		
	}
	
	
	
	long[] X,Y;
	public Sol(){
		X=new long[3];
		Y=new long[3];
		for(int i=0;i<3;i++){
			var d=ria();
			X[i]=d[0];Y[i]=d[1];
		}
	}
	long gcd(long a,long b){
		return a==0?b:gcd(b%a,a);
	}



	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}