Let $P, Q,$ and $R$ be propositional variables. Suppose we define a ternary connective $h(P, Q, R) = (P \land \neg Q) \lor (\neg P \land R)$. How many of the $2^3 = 8$ possible valuations of $(P, Q, R)$ make $h(P, Q, R)$ logically equivalent to $P \oplus Q \oplus R$?