ll H, W, LA, LB, KA, KB;

bool chk(ll k){
  ll lrng = (H + LA - 1)/ LA;
  // ll rrng = (W + LB - 1)/ LB;
  rep(i, lrng + 1) {
    ll j = (k - i);
    ll filled_alt = i * KA + j * KB;

    ll lsize = min(H, i * LA);
    ll rsize = min(W, j * LB);
    ll filled = lsize * rsize;
    ll rem = H * W - filled;
    if (rem <= filled_alt) return true;
  }
  return false;
}

{
  rd(H, W, LA, LB, KA, KB);
  int k;
  ll ans = bsearch_min[int,k,1,H+W](chk(k));
  wt(ans);
}