二叉树的重建

Descr iption

给定二叉树的先序遍历序列和中序遍历序列，重建二叉树，并对其进行后序遍历。

Input

第一行为一个整数t（0<t<10），表示测试用例的数目。以下t行，每行输入一个测试用例，包含两个字符序列s1和s2，其中s1为一棵二叉树的先序遍历序列，s2为中序遍历序列。s1和s2之间用一个空格分隔。序列只包含大写字母，并且每个字母最多只会出现一次。

Output

对于每个测试用例，用单独一行输出对该二叉树进行后序遍历得到的字符序列，字符间没有空格。

-Binary tree reconstruction

Descr iption

Given binary tree in preorder traversal sequences and sequences, reconstruction binary tree, and its post-order traversal.

Input

The first is an integer t (0 <t <10), that the number of test cases. The following t lines, each line of input a test case contains two character sequences s1 and s2, where s1 is a binary tree traversal sequence first, s2 is the preorder sequence. between s1 and s2 are separated by a space. Sequence contains only uppercase letters, and each letter will only appear once.

Output

For each test case, output a single line after the binary tree traversal sequence of characters obtained, with no spaces between characters.