I am solving a problem that is asking to provide an equivalent for $\neg ((a \wedge b) \Leftrightarrow c)$ and the equivalent shouldn't contain $\wedge$ (and), $\Rightarrow$ (implication) or $\Leftrightarrow$ (iff). What I have worked out is:
$\neg(\neg((\neg a \vee \neg b) \vee \neg c) \vee \neg(\neg(\neg a \vee \neg b) \vee c))$
I wonder based on the requirement stated above, is there a shorter equivalent for my answer?
$\oplus$ is not allowed in the requirement either.