CF29D.Ant on the Tree

Connected undirected graph without cycles is called a tree. Trees is a class of graphs which is interesting not only for people, but for ants too.

An ant stands at the root of some tree. He sees that there are n vertexes in the tree, and they are connected by n - 1 edges so that there is a path between any pair of vertexes. A leaf is a distinct from root vertex, which is connected with exactly one other vertex.

The ant wants to visit every vertex in the tree and return to the root, passing every edge twice. In addition, he wants to visit the leaves in a specific order. You are to find some possible route of the ant.

不含环的连通无向图称为树。树是一类不仅对人类，而且对蚂蚁也颇具吸引力的图。

一只蚂蚁站在某棵树的根节点上。它发现这棵树共有 $n$ 个顶点，并通过 $n-1$ 条边相连，使得任意两个顶点之间均存在一条路径。叶子节点是指不同于根节点、且仅与另一个顶点相连的顶点。

蚂蚁希望遍历树中的每个顶点并最终返回根节点，且每条边恰好经过两次。此外，它还希望按特定顺序访问所有叶子节点。你需要为这只蚂蚁找出一条满足上述条件的可行路径。

The first line contains integer n (3 ≤ n ≤ 300) — amount of vertexes in the tree. Next n - 1 lines describe edges. Each edge is described with two integers — indexes of vertexes which it connects. Each edge can be passed in any direction. Vertexes are numbered starting from 1. The root of the tree has number 1. The last line contains k integers, where k is amount of leaves in the tree. These numbers describe the order in which the leaves should be visited. It is guaranteed that each leaf appears in this order exactly once.

第一行包含一个整数 $n$（$3 \leq n \leq 300$）——树中顶点的数量。接下来的 $n-1$ 行描述边，每条边由两个整数表示——该边所连接的两个顶点的编号。每条边可沿任意方向遍历。顶点编号从 $1$ 开始，树的根节点编号为 $1$。最后一行包含 $k$ 个整数，其中 $k$ 是树中叶子节点的数量。这些数字描述了叶子节点应被访问的顺序。保证每个叶子节点在此顺序中恰好出现一次。

If the required route doesn't exist, output -1. Otherwise, output 2_n_ - 1 numbers, describing the route. Every time the ant comes to a vertex, output it's index.

如果所需路径不存在，则输出 -1。否则，输出 2n - 1 个数字，描述该路径：每次蚂蚁到达一个顶点时，输出该顶点的编号。