I was given the following question

Explain the logical connective “or” using only the notions of “not” and “and,” that is to say, write down an expression in P and Q using only the logical connectives “not” and “and” that is logically equivalent to “P or Q.”

I know that the the logical of "or" using P and Q is

P Q

I also wrote the truth table for P Q and cannot think of a way to write "or" using the notions not and and. Can anyone lead me in the write direction?

Thanks