P, Q, ((P→Q)→R) ⊢ R using only modus ponens

Question

Can $R$ be inferred from $P$, $Q$, and $(P \to Q) \to R$ using only modus ponens?
My understanding is that it can, as shown below, but I was told this was incorrect.

Proof of ${P, Q, (P \to Q) \to R} \vdash R$ using modus ponens:

P, Q, (P->Q)->R  : Given  
Q, (Q)->R        : By Modus Ponens  
R                : By Modus Ponens