Problems Status Rank Problem 1111 Catenyms Time Limit: 1000msMemory Limit: 65536kb Description A catenym is a pair of words separated by a period such that the last letter of the first word is the same as the last letter of the second. For example, the following are catenyms: ```dog.gopher gopher.rat rat.tiger aloha.aloha arachnid.dog ``` A compound catenym is a sequence of three or more words separated by periods such that each adjacent pair of words forms a catenym. For example, ```aloha.aloha.arachnid.dog.gopher.rat.tiger ``` Given a dictionary of lower case words, you are to find a compound catenym that contains each of the words exactly once. Input The first line of standard input contains t, the number of test cases. Each test case begins with 3 <= n <= 1000 - the number of words in the dictionary. n distinct dictionary words follow; each word is a string of between 1 and 20 lowercase letters on a line by itself. Output For each test case, output a line giving the lexicographically least compound catenym that contains each dictionary word exactly once. Output "***" if there is no solution. Sample Input ```2 6 aloha arachnid dog gopher rat tiger 3 oak maple elm``` Sample Output ```aloha.arachnid.dog.gopher.rat.tiger ***```