B'You are given an integer n . Let 's define s(n) as the string "BAN" concatenated n times. For example, s(1) = "BAN", s(3) = "BANBANBAN". Note that the length of the string s(n) is equal to 3n . Consider s(n) . You can perform the following operation on s(n) any number of times (possibly zero): You want the string "BAN" to not appear in s(n) as a subsequence. What 's the smallest number of operations you have to do to achieve this? Also, find one such shortest sequence of operations. A string a is a subsequence of a string b if a can be obtained from b by deletion of several (possibly, zero or all) characters. 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 description of the test cases follows. The only line of each test case contains a single integer n (1 <= q n <= q 100) . For each test case, in the first line output m ( 0 <= m <= 10^5 ) -- the minimum number of operations required. It 's guaranteed that the objective is always achievable in at most 10^5 operations under the constraints of the problem. Then, output m lines. The k -th of these lines should contain two integers i_k , j_k (1 <= q i_k, j_k <= q 3n, i_k ne j_k) denoting that you want to swap characters at indices i_k and j_k at the k -th operation. After all m operations, "BAN" must not appear in s(n) as a subsequence. If there are multiple possible answers, output any. In the first testcase, s(1) = "BAN", we can swap s(1)_1 and s(1)_2 , converting s(1) to "ABN", which does not contain "BAN" as a subsequence. In the second testcase, s(2) = "BANBAN", we can swap s(2)_2 and s(2)_6 , converting s(2) to "BNNBAA", which does not contain "BAN" as a subsequence. '...