Problem: You are given an array a consisting of n integers (it is guaranteed that n is even, i.e. divisible by 2). All a_i does not exceed some integer k.

Your task is to replace the minimum number of elements (replacement is the following operation: choose some index i from 1 to n and replace a_i with some integer in range [1; k]) to satisfy the following conditions:

  * after all replacements, all a_i are positive integers not greater than k; 
  * for all i from 1 to n/2 the following equation is true: a_i + a_{n - i + 1} = x, where x should be the same for all n/2 pairs of elements. 



You have to answer t independent test cases.

Input

The first line of the input contains one integer t (1 ≤ t ≤ 10^4) — the number of test cases. Then t test cases follow.

The first line of the test case contains two integers n and k (2 ≤ n ≤ 2 ⋅ 10^5, 1 ≤ k ≤ 2 ⋅ 10^5) — the length of a and the maximum possible value of some a_i correspondingly. It is guratanteed that n is even (i.e. divisible by 2). The second line of the test case contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ k), where a_i is the i-th element of a.

It is guaranteed that the sum of n (as well as the sum of k) over all test cases does not exceed 2 ⋅ 10^5 (∑ n ≤ 2 ⋅ 10^5, ∑ k ≤ 2 ⋅ 10^5).

Output

For each test case, print the answer — the minimum number of elements you have to replace in a to satisfy the conditions from the problem statement.

Example

Input


4
4 2
1 2 1 2
4 3
1 2 2 1
8 7
6 1 1 7 6 3 4 6
6 6
5 2 6 1 3 4


Output


0
1
4
2

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int main() {
  int t, n, k;
  cin >> t;
  while (t--) {
    cin >> n >> k;
    vector<int> a(n), pref(2 * k + 1, 0), cnt(2 * k + 1, 0);
    for (int i = 0; i < n; ++i) cin >> a[i];
    for (int i = 0; i * 2 < n; ++i) {
      int s = a[i] + a[n - i - 1];
      ++cnt[s];
      ++pref[min(a[i], a[n - i - 1]) + 1];
      --pref[max(a[i], a[n - i - 1]) + k + 1];
    }
    for (int i = 1; i < pref.size(); ++i) pref[i] += pref[i - 1];
    int res = n;
    for (int x = 2; x <= 2 * k; ++x) {
      int cur_res = n - pref[x] - cnt[x];
      res = min(res, cur_res);
    }
    cout << res << endl;
  }
  return 0;
}