In the topological semantics of modal logic, a propositional formula is evaluated over a topological space $(X, \tau)$. The modal operator \Box A is interpreted as the interior of the set $A$ (denoted $I(A)$), and \Diamond A is interpreted as the closure of $A$ (denoted $Cl(A)$). The classical implication $A \implies B$ is interpreted as the set $(X \setminus A) \cup B$.

Let $X = \{1, 2, 3\}$ with the topology $\tau = \{\emptyset, \{1\}, \{1, 2\}, X\}$. Suppose the valuation of the proposition $P$ is $V(P) = \{1, 3\}$. Determine the valuation of the modal formula \Box(\Diamond P \implies P).