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(){
        
        long lcm=Y[0]*Y[1]/gcd(Y[0],Y[1]);
        long tmp=-1;
        for(long x=X[0];x<=lcm*2;x+=Y[0]){
            if(x%Y[1]==X[1]){tmp=x;break;}
        }
        
        if(tmp==-1){
            Console.WriteLine(-1);
            return;
        }
        if(tmp==0)tmp+=lcm;
        long lcm2=lcm*Y[2]/gcd(lcm,Y[2]);
        long ans=-1;
        for(long x=tmp;x<=lcm2*2;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=rla();
            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));}
}