Hello

I am running into problems with the following:

∃x(P (x) ⇒ (Q(x) ⇒ R(x)))⇐⇒ (¬∀xP (x) ∨ ¬∀yQ(y) ∨ ∃zR(z))

Although I do not master logical equivalences, I have been able to solve some earlier. However, since this problem has quantifiers, I don't know how to approach it.

Any help is highly appreciated.