Taylor the tailor has just finished work on millions of outfits [at the request of her friend Dorothy](https://www.facebook.com/codingcompetitions/hacker-cup/2021/round-2/problems/A). Now she is left with a major cleanup job in her studio. A given room in the studio has \(N\) leftover pieces of strings scattered about, indexed from \(1\) to \(N\). The \(i\)th piece of string has a length of \(L_i\) centimeters. Taylor has two spools, so she would like to concatenate these strings into two threads by fusing their ends together. She plans to concatenate several pieces of string into a first thread to be stored on her first spool, and then several other pieces into a second thread to store on her second spool. A concatenated thread has length equal to the sum of the lengths of the individual strings. Pieces of string not used in either thread will be thrown away, and obviously, any given piece of string can be used in only one of the threads. Taylor is also very particular about the cleanup process: - She would like her two concatenated threads to be exactly the same positive length, and - She would like to throw away at most \(K\) pieces of string in total to reduce waste. Please help Taylor determine how to concatenate strings to satisfy these requirements, if possible. If there are multiple answers, any one will be accepted. # Constraints \(1 \le T \le 80\) \(2 \le N \le 200{,}000\) \(1 \le L_i \le 200{,}000\) \(\min(N - 2, 25) \le K \le N - 2\) The sum of \(N\) across all rooms is at most \(700{,}000\). # Input Input begins with an integer \(T\), the number of rooms in the studio. For each room, there is first a line containing two space-separated integers \(N\) and \(K\). Then, there is a line containing \(N\) space-separated integers, \(L_{1..N}\). # Output For the \(i\)th room, output a line containing *"Case #i: "* followed by "Possible" if it's possible to form two equal-length threads without throwing away more than \(K\) pieces of string, or "Impossible" otherwise. If it's possible, print two more lines of space-separated integers: the indices of the strings in the first thread, and the indices of the strings in the second thread. # Sample Explanation In the first room, one valid option for Taylor to form two equal-length threads is by concatenating strings \(1\), \(2\), and \(5\) (with a total length of \(1 + 4 + 2 = 7\,\)cm) in one, and just using string \(3\) (with length \(7\,\)cm) in the other. This results in \(2\) strings being thrown away, which is no more than \(K=4\). In the second room, no two strings have the same length, and no two strings' lengths add up to the remaining string's length. Therefore, it is impossible to satisfy the requirements. In the third room, since strings \(2\) and \(5\) both have the same length of \(1\,\)cm, one possible answer is to simply keep them and throw away the other \(8\). In the fourth room, all \(30\) strings have equal length. One possible answer is to concatenate any \(15\) strings in one thread, and the remaining \(15\) in the other. Since we are permitted to throw away up to \(25\) strings, another possible answer is to concatenate any \(3\) strings in each thread and throw away the remaining \(24\). Note that we cannot keep just \(1\) string per thread, as that would result in \(28\) strings being thrown away, which is more than \(25\). In the fifth room, the first thread can be made of the strings with lengths \(10\,\)cm and \(73\,\)cm, and the second thread of strings with lengths \(8\,\)cm and \(75\,\)cm. **Note: For sample cases 1, 3, 4, and 5, other outputs would also be accepted.**