Give you a binary tree T. Please print the:

pre/ in/ post order Traversal of the tree.

First line is an integer T, which is the number of test cases. (1 <= T <= 50)

For each test case, there will be an integer in a single line N (1 <= N <= 1024). N is the number of nodes. The nodes are numbered from 1 to N.

Then there will be N – 1 lines with two integer x, y for each line. (1 <= x, y <= N)

x y means x is the farther of y. What’s more, we guarantee the input file is a tree. And the child appears first is the left child, the other one appears later is right child.

For each test case, you should print three lines:

The 1^st/2^nd/3^rd line is the pre/in/post order traversal of the Tree.

Easy problem.