Another Standard Problem

You are given a tree of $N$ vertices. Vertex $i$ has the color $A_i$ associated to it. Initially, the root of the tree is vertex $1$. Process $Q$ queries on this tree, each being one of the following three types: - `1 u c`: for every vertex $x$ such that $x$ lies in the subtree of $u$, set $A_x$ to $c$ - `2 u`: change the root of the tree to $u$ - `3 u c`: count the number of vertices in the su