Amazing Tree Tree is an amazing data structure in computer science and many data can be represented as tree. For example, a black-white image can be represented as a quad tree and the arithmetic expression can be represented as a binary tree, a file system is also a tree, etc. Today, we introduce a method that can represent a general tree by using a string Figure 2: file system The tree in figure 1 can be represented as a file system in figure 2, and if we replace each file in figure 2 as a bracket pair 0 and maintain the relationship of the file folders, we would get the corresponding string in figure 3. In summary, a tree can be represented as a string of bracket pairs and also a string of brcket pairs represents a tree. Now, here comes the task. You are given a tree, for each node i in the tree, the weight of node i s defined by the number of nodes in the sub-tree rooted at node i The task is to calculate the XOR value of the weight of all nodes in the tree