Given a tree G(V, E) and its root, print its level-order traversal, where we visit all of the nodes at the same level before going to the lower ones. Each node is labeled by a unique integer number, and in case that the node has more than one child, the one who is labeled by smaller number should be visited first.
The first line of input is a single integer T (T ≤ 100), denoting the number of test cases. Each test case started with an integer pair N (N ≤ 1000) and R, indicating the number of nodes and the root number respectively. The following N - 1 lines contain pairs of integers ui and vi (1 ≤ ui, vi ≤ N), each in a line, which means ui and vi are adjacent.
For each test case, output “Case i:” denoting the traversal of i-th test case on a line. Then, for each visited node, started from the root, print the labeled number. Every two successive numbers are separated by a space characters. Print a blank line between test cases.