#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 1e8

typedef long long ll;

ll gcd(ll a, ll b) {
    if (b == 0)
        return a;
    else
        return gcd(b,a%b);
}

ll lcm(ll a, ll b) {
    return a*b/gcd(a,b);
}

int main() {
    ll i;
    ll x[3], y[3];
    rep (i,3) cin >> x[i] >> y[i];
    rep (i,1000001) {
        ll n = y[0]*i+x[0];
        if (n != 0 && n%y[1]==x[1]) {
            y[1] = lcm(y[0],y[1]);
            x[1] = n;
            break;
        }
    }
    if (i == 1000001) {
        cout << -1 << endl;
        return 0;
    }
    rep (i,1000001) {
        ll n = y[1]*i+x[1];
        if (n != 0 && n%y[2]==x[2]) {
            cout << n << endl;
            return 0;
        }
    }
    cout << -1 << endl;
    return 0;
}