Avoid Monster

You are given a tree with $N$ nodes and $N-1$ edges. The nodes are numbered from $1$ to $N$. You need to answer $Q$ queries. Each query consists of two distinct nodes $A$ and $B$. A monster starts at node $A$ and moves as follows: - Every second, it moves one step toward $B$ along the unique path in the tree. - When the monster reaches $B$, it immediately turns around and moves one step per secon