You are given a list of strings over the alphabet A (for adenine), C (cytosine), G (guanine), and T (thymine), and your task is to find the shortest string (which is typically not listed) that contains all the given strings as substrings. If there are several such strings of shortest length, find the one that is lexicographically smallest.

Input starts with an integer T (≤ 35), denoting the number of test cases.

Each case starts with an integer denoting the number of strings n (1 ≤ n ≤ 15) in a single line. Then these n strings (1 ≤ length ≤ 100) follow, one in each line, and they consist of the letters 'A', 'C', 'G' and 'T' only.

For each case, print the case number and the shortest (and lexicographically smallest) string according to the description above.