Can you prove the following sequent by using the natural deduction rules?

Question

(p→q)→r, s→¬p , t , (¬s∧t) → q ⊢ r Any help would be appreciated

Answer 1

You can start with ¬r, and find the contradiction (t∧¬t). It took me 14 steps. Maybe it is not the best way, but reductio ad absurdum usually works fine :)