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

bool chk(ll k){
  ll lrng = (H+LA-1)/LA;
  rep(i, min(lrng,k) + 1) {
    ll j = (k - i);
    ll filled = i*KA + j*KB;

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