#include <bits/stdc++.h>

using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}
template<class T> inline T sqr(T x) {return x*x;}

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;

#define all(a)  (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define each(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define exist(s,e) ((s).find(e)!=(s).end())
#define range(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)  range(i,0,n)
#define clr(a,b) memset((a), (b) ,sizeof(a))
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

const double eps = 1e-10;
const double pi  = acos(-1.0);
const ll INF =1LL << 62;
const int inf =1 << 29;

ll X[3],Y[3];

int main(void){
	rep(i,3) cin >> X[i] >> Y[i];
	ll ans=X[0];
	rep(i,Y[1]){
		if(ans!=0&&ans%Y[1]==X[1]) break;
		ans+=Y[0];
	}
	rep(i,Y[2]){
		if(ans!=0&&ans%Y[2]==X[2]) break;
		ans+=Y[0]/__gcd(Y[0],Y[1])*Y[1];
	}
	if(ans%Y[0]!=X[0]||ans%Y[1]!=X[1]||ans%Y[2]!=X[2]) ans=-1;
	cout << ans << endl;
	return 0;
}