By De Morgan's Laws, neg(PlandQ)\\neg(P \\land Q)neg(PlandQ) is equivalent to:
negPlornegQ\\neg P \\lor \\neg QnegPlornegQ
PlorQP \\lor QPlorQ
PimpliesQP \\implies QPimpliesQ
negPlandnegQ\\neg P \\land \\neg QnegPlandnegQ