#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(long long i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
 
#define MOD 1000000007

int main(){
  int x1,y1,x2,y2,x3,y3;
  cin>>x1>>y1;
  cin>>x2>>y2;
  cin>>x3>>y3;
  if(y1>y2){
    swap(y1,y2);
    swap(x1,x2);
  }
  if(y2>y3){
    swap(y2,y3);
    swap(x2,x3);
  }
  rep(i,0,60000000){
    long long a = (long long)y3*i+x3;
    if(a%y1==x1&&a%y2==x2){
      cout << a << endl;
      return 0;
    }
  }
  cout << -1 << endl;
  return 0;
}