#include <bits/stdc++.h>

#define rep(i, n) for (int (i) = 0; (i) < (int)(n); (i)++)

const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
using namespace std;
typedef long long ll;

ll X[3], Y[3];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    for (int i = 0; i < 3; i++) {
        cin >> X[i] >> Y[i];
    }
    for (ll i = 0; i < Y[1]; i++) {
        ll tmp = Y[0] * i + X[0];
        if (tmp == 0) continue;
        if ((tmp-X[1]) % Y[1] == 0) {
            ll lcm = Y[0] / __gcd(Y[0], Y[1]) * Y[1];
            for (ll j = 0; j < Y[2]; j++) {
                ll ans = tmp+j*lcm;
                if ((ans-X[2]) % Y[2] == 0) {
                    cout << ans << endl;
                    return 0;
                }
            }
        }
    }
    cout << -1 << endl;
    return 0;
}