B'AquaMoon had n strings of length m each. n is an odd number. When AquaMoon was gone, Cirno tried to pair these n strings together. After making frac{n-1}{2} pairs, she found out that there was exactly one string without the pair! In her rage, she disrupted each pair of strings. For each pair, she selected some positions (at least 1 and at most m ) and swapped the letters in the two strings of this pair at the selected positions. For example, if m = 6 and two strings "abcdef" and "xyzklm" are in one pair and Cirno selected positions 2 , 3 and 6 she will swap 'b ' with 'y ', 'c ' with 'z ' and 'f ' with 'm '. The resulting strings will be "ayzdem" and "xbcklf". Cirno then stole away the string without pair and shuffled all remaining strings in arbitrary order. AquaMoon found the remaining n-1 strings in complete disarray. Also, she remembers the initial n strings. She wants to know which string was stolen, but she is not good at programming. Can you help her? This problem is made as interactive. It means, that your solution will read the input, given by the interactor. But the interactor will give you the full input at the beginning and after that, you should print the answer. So you should solve the problem, like as you solve the usual, non-interactive problem because you won 't have any interaction process. The only thing you should not forget is to flush the output buffer, after printing the answer. Otherwise, you can get an "Idleness limit exceeded" verdict. Refer to the interactive problems guide for the detailed information about flushing the output buffer. The input consists of multiple test cases. The first line contains a single integer t ( 1 <= q t <= q 100 ) -- the number of test cases. The first line of each test case contains two integers n , m ( 1 <= q n <= q 10^5 , 1 <= q m <= q 10^5 ) -- the number of strings and the length of each string, re'...