Roots of a Tree

You are given a tree with N nodes, numbered from 1 to N. You need to handle the queiries of the following two types: - + x y. Add a path going from the node x to the node y (or from y to x because it's actually irrelevant). We will never add the path that is already a present one. - - x y. Delete the path going from the node x to the node y. It is guaranteed that such path exists and after its l