\begin{logicproof}{2} p \implies q & \prem \\ p \land (r \lor q) & \prem \\ \begin{subproof} q \implies p & \assum \\ r \lor q & $\ande{2} 2$ \\ p & $\ande{1} 2$ \\ q & $\impe 1,5$ \\ (s \land t) \lor q & $\ori{2} 6$ \\ ((s \land t) \lor q) \land (r \lor q) & $\andi 7,4$ \end{subproof} (q \implies p) \implies ((s \land t) \lor q) \land (r \lor q) & $\impi 3-7$ \end{logicproof}