#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (decltype(n) i = 0; i < (n); ++i)
#define rep3(i, s, n) for (decltype(n) i = (s); i < (n); ++i)
#define repR(i, n) for (decltype(n) i = (n)-1; i >= 0; --i)
#define rep3R(i, s, n) for (decltype(n) i = (n)-1; i >= (s); --i)
#define repit(it, c) for (auto it = (c).begin(); it != (c).end(); ++it)
#define all(x) ::std::begin(x), ::std::end(x)

using ll = long long;

template <typename T, typename U>
inline bool chmax(T &current, const U &test) {
  if (current < test) {
    current = test;
    return true;
  }
  return false;
}
template <typename T, typename U>
inline bool chmin(T &current, const U &test) {
  if (current > test) {
    current = test;
    return true;
  }
  return false;
}

const int64_t INFL = pow(10, 18);
const int INF = 2 * pow(10, 9);

ll ext_Euclid(ll a, ll b, ll &p, ll &q) {
  if (b == 0) {
    p = 1;
    q = 0;
    return a;
  }
  ll d = ext_Euclid(b, a % b, q, p);
  q -= a / b * p;
  return d;
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  constexpr char endl = '\n';
  ///////////////////////////

  vector<ll> x(3), y(3);
  rep(i, 3) { cin >> x[i] >> y[i]; }

  ll ans = 0;
  ll mod = 1;
  rep(i, 3) {
    // mod p + y[i] q == gcd(mod, y[i])
    ll p, q;
    ll d = ext_Euclid(mod, y[i], p, q);
    if ((ans - x[i]) % d != 0) {
      cout << -1 << endl;
      return 0;
    }
    ll s = (ans - x[i]) / d;
    // s mod p + s y[i] q == ans - x[i]
    ans = ans - mod * (s * p % (y[i] / d));
    mod = mod / d * y[i];
    ans = (ans % mod + mod) % mod;
  }
  if (ans == 0) {
    ans = y[0];
    ll gcd = y[0];
    ll p, q;
    rep(i, 2) {
      gcd = ext_Euclid(ans, y[1 + i], p, q);
      ans = ans * y[1 + i] / gcd;
    }
  }
  cout << ans << endl;
}