#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <limits>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <complex>

using namespace std;

#define INF (INT_MAX/3)
#define PI (2*acos(0.0))
#define EPS (1e-8)

typedef long long ll;
typedef unsigned long long ull;

int X[3], Y[3];

ll solve(){
  ll P = X[0], lcm;
  for(int i = 0; i <= Y[0]; i++){
    if(P % Y[1] == X[1]) { lcm = Y[0] * Y[1] / __gcd(Y[0], Y[1]); break; }
    P += Y[0];
  }
  if(P == 0) return -1;

  ll Q = P;
  for(int i = 0; i <= Y[1]; i++){
    if(Q % Y[2] == X[2]) return Q;
    Q += lcm;
  }
  return -1;
}

int main(){
  ios_base::sync_with_stdio(0);
  for(int i = 0; i < 3; i++) cin >> X[i] >> Y[i];
  cout << solve() << endl;
  return 0;
}