Probability Distributions $P(A^c\cap B^c)$? How can i do this distribution from Pitman probability textbook? I dont know how this expands. Do i use the compliment rule? Difference rule? Inclusion-exclusion?

Note that $A^c\cap B^c=(A\cup B)^c$ $$ P(A^c\cap B^c)=1-P(A\cup B)=1-P(A)-P(B)+P(A\cap B). $$