Para-monkey

Param has a monkey para-monkey, so he must be living on a tree, right? There is a tree with $n$ vertices (a tree is a connected undirected graph without cycles), every node of this tree has a value attached to it. You are now given $q$ queries, each query is described by two integers $x$ and $y$. Now, we define two nodes $a$ and $b$ as: $a = (x \oplus last )$ % $n + 1$. $b = (y \oplus la