/* -*- coding: utf-8 -*-
 *
 * 186.cc: No.186 中華風 (Easy) - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

ll xs[3], ys[3];

/* main */

int main() {
  for (int i = 0; i < 3; i++) cin >> xs[i] >> ys[i];

  ll y01 = ys[0] * ys[1] / __gcd((int)ys[0], (int)ys[1]);
  
  for (ll k = 0; k <= ys[1]; k++) {
    ll z0 = xs[0] + k * ys[0];
    if (z0 % ys[1] == xs[1]) {
      for (ll l = 0; l <= ys[2]; l++) {
	//printf("k=%lld,l=%lld\n", k, l);
	ll z1 = z0 + y01 * l;
	if (z1 > 0 && z1 % ys[2] == xs[2]) {
	  printf("%lld\n", z1);
	  return 0;
	}
      }
    }
  }

  puts("-1");
  return 0;
}