\begin{logicproof}{1} \neg p \imp \lnot q & \prem \\ q & \prem\\ \begin{subproof} \lnot p & \assum \\ \lnot q & $\impe 3,1$\\ \bot & $\nege 2,4$ \end{subproof} p & $\PBC 3-5$ \end{logicproof}