B"Recall that a permutation of length n is an array where each element from 1 to n occurs exactly once. For a fixed positive integer d , let's define the cost of the permutation p of length n as the number of indices i (1 <= i < n) such that p_i cdot d = p_{i + 1} . For example, if d = 3 and p = [5, 2, 6, 7, 1, 3, 4] , then the cost of such a permutation is 2 , because p_2 cdot 3 = p_3 and p_5 cdot 3 = p_6 . Your task is the following one: for a given value n , find the permutation of length n and the value d with maximum possible cost (over all ways to choose the permutation and d ). If there are multiple answers, then print any of them. The first line contains a single integer t ( 1 <= t <= 500 ) -- the number of test cases. The single line of each test case contains a single integer n ( 2 <= n <= 2 cdot 10^5 ). The sum of n over all test cases does not exceed 2 cdot 10^5 . For each test case, print the value d in the first line, and n integers in the second line -- the permutation itself. If there are multiple answers, then print any of them. "...