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
import java.io.*;
import java.util.*;

public class Main implements Runnable {
	boolean oj = false;
	Reader scn;
	PrintWriter out;
	String INPUT = "";

	void solve() {
		int t = scn.nextInt();
		while(t-- > 0) {
			int n = scn.nextInt();
			int[][] arr = new int[n][2], need = new int[n][2], copy = new int[n][2];
			
			for(int i = 0; i < n; i++) {
				copy[i][0] = need[i][0] = arr[i][0] = scn.nextInt();
				need[i][1] = i + 1;
				copy[i][1] = arr[i][1] = -(i + 1);
			}
			
			Arrays.sort(need, (o1, o2) -> o1[0] != o2[0] ? o1[0] - o2[0] : o1[1] - o2[1]);
			for(int i = 0; i < n; i++) {
				for(int j = 0; j < n; j++) {
					if(arr[j][1] > 0) {
						continue;
					}
					if(arr[j][0] == need[i][0] && need[i][1] + arr[j][1] == 0) {
						arr[j][1] = i;
					}
				}
			}
			
			StringBuilder sb = new StringBuilder();
			int ans = 0;
			for(int i = 0; i < n; i++) {
				if(arr[i][1] == i) {
					continue;
				}
				int pos = -1;
				for(int j = 0; j < n; j++) {
					if(arr[j][1] == i) {
						pos = j;
					}
				}
				
				assert pos > i;
				if(pos == i + 1) {
					if(i == n - 2) {
						ans = -1;
						break;
					}
					rotate(arr, i);
					rotate(arr, i);
					sb.append(i + 1 + " ");
					sb.append(i + 1 + " ");
					ans += 2;
				} else {
					while(pos > i + 1) {
						rotate(arr, pos - 2);
						sb.append(pos - 1 + " ");
						pos = pos - 2;
						ans++;
					}
					if(pos != i) {
						rotate(arr, i);
						rotate(arr, i);
						sb.append(i + 1 + " ");
						sb.append(i + 1 + " ");
						ans += 2;
					}
				}
			}
			
			if(ans != -1) {
				assert ans <= n * n;
				out.println(ans);
				out.println(sb);
				continue;
			}
			
			boolean found = false;
			for(int i = n - 1; i > 0; i--) {
				if(need[i][0] == need[i - 1][0]) {
					int temp = need[i][1];
					need[i][1] = need[i - 1][1];
					need[i - 1][1] = temp;
					found = true;
					break;
				}
			}
			if(!found) {
				out.println(-1);
				continue;
			}
			
			for(int i = 0; i < n; i++) {
				arr[i][0] = copy[i][0];
				arr[i][1] = copy[i][1];
			}
			
			for(int i = 0; i < n; i++) {
				for(int j = 0; j < n; j++) {
					if(arr[j][1] > 0) {
						continue;
					}
					if(arr[j][0] == need[i][0] && need[i][1] + arr[j][1] == 0) {
						arr[j][1] = i;
					}
				}
			}
			
			sb = new StringBuilder();
			ans = 0;
			for(int i = 0; i < n; i++) {
				if(arr[i][1] == i) {
					continue;
				}
				int pos = -1;
				for(int j = 0; j < n; j++) {
					if(arr[j][1] == i) {
						pos = j;
					}
				}
				
				assert pos > i;
				if(pos == i + 1) {
					if(i == n - 2) {
						ans = -1;
						break;
					}
					rotate(arr, i);
					rotate(arr, i);
					sb.append(i + 1 + " ");
					sb.append(i + 1 + " ");
					ans += 2;
				} else {
					while(pos > i + 1) {
						rotate(arr, pos - 2);
						sb.append(pos - 1 + " ");
						pos = pos - 2;
						ans++;
					}
					if(pos != i) {
						rotate(arr, i);
						rotate(arr, i);
						sb.append(i + 1 + " ");
						sb.append(i + 1 + " ");
						ans += 2;
					}
				}
			}
			
			if(ans != -1) {
				assert ans <= n * n;
				out.println(ans);
				out.println(sb);
			} else {
				out.println(-1);
			}
		}
	}
	
	void rotate(int[][] arr, int pos) {
		int[] temp = arr[pos + 2];
		arr[pos + 2] = arr[pos + 1];
		arr[pos + 1] = arr[pos];
		arr[pos] = temp;
	}

	public void run() {
		long time = System.currentTimeMillis();
		boolean judge = System.getProperty("ONLINE_JUDGE") != null || oj;
		out = new PrintWriter(System.out);
		scn = new Reader(judge);
		solve();
		out.flush();
		if (!judge) {
			System.out.println(Arrays.deepToString(new Object[] { System.currentTimeMillis() - time + " ms" }));
		}
	}

	public static void main(String[] args) {
		new Thread(null, new Main(), "Main", 1 << 28).start();
	}

	class Reader {
		InputStream is;

		public Reader(boolean oj) {
			is = oj ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		}

		byte[] inbuf = new byte[1024];
		public int lenbuf = 0, ptrbuf = 0;

		int readByte() {
			if (lenbuf == -1)
				throw new InputMismatchException();
			if (ptrbuf >= lenbuf) {
				ptrbuf = 0;
				try {
					lenbuf = is.read(inbuf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (lenbuf <= 0)
					return -1;
			}
			return inbuf[ptrbuf++];
		}

		boolean isSpaceChar(int c) {
			return !(c >= 33 && c <= 126);
		}

		int skip() {
			int b;
			while ((b = readByte()) != -1 && isSpaceChar(b))
				;
			return b;
		}

		String next() {
			int b = skip();
			StringBuilder stringB = new StringBuilder();
			while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != ' ')
				stringB.appendCodePoint(b);
				b = readByte();
			}
			return stringB.toString();
		}

		String nextLine() {
			int b = skip();
			StringBuilder stringB = new StringBuilder();
			while ((!isSpaceChar(b) || b == ' ')) { // when nextLine, (isSpaceChar(b) && b != ' ')
				stringB.appendCodePoint(b);
				b = readByte();
			}
			return stringB.toString();
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		char nextChar() {
			return (char) skip();
		}

		char[] next(int n) {
			char[] buff = new char[n];
			int b = skip(), p = 0;
			while (p < n && !(isSpaceChar(b))) {
				buff[p++] = (char) b;
				b = readByte();
			}
			return n == p ? buff : Arrays.copyOf(buff, p);
		}

		int nextInt() {
			int num = 0, b;
			boolean minus = false;
			while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
				;
			if (b == '-') {
				minus = true;
				b = readByte();
			}

			while (true) {
				if (b >= '0' && b <= '9') {
					num = num * 10 + (b - '0');
				} else {
					return minus ? -num : num;
				}
				b = readByte();
			}
		}

		long nextLong() {
			long num = 0;
			int b;
			boolean minus = false;
			while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
				;
			if (b == '-') {
				minus = true;
				b = readByte();
			}

			while (true) {
				if (b >= '0' && b <= '9') {
					num = num * 10 + (b - '0');
				} else {
					return minus ? -num : num;
				}
				b = readByte();
			}
		}

		long[] nextLongArr(int n) {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		int[] nextIntArr(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		char[][] nextMat(int n, int m) {
			char[][] map = new char[n][];
			for (int i = 0; i < n; i++)
				map[i] = next(m);
			return map;
		}

		long[][] next2Long(int n, int m) {
			long[][] arr = new long[n][];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLongArr(m);
			}
			return arr;
		}

		int[][] next2Int(int n, int m) {
			int[][] arr = new int[n][];
			for (int i = 0; i < n; i++) {
				arr[i] = nextIntArr(m);
			}
			return arr;
		}

		long[] shuffle(long[] arr) {
			Random r = new Random();
			for (int i = 1, j; i < arr.length; i++) {
				j = r.nextInt(i);
				arr[i] = arr[i] ^ arr[j];
				arr[j] = arr[i] ^ arr[j];
				arr[i] = arr[i] ^ arr[j];
			}
			return arr;
		}

		int[] shuffle(int[] arr) {
			Random r = new Random();
			for (int i = 1, j; i < arr.length; i++) {
				j = r.nextInt(i);
				arr[i] = arr[i] ^ arr[j];
				arr[j] = arr[i] ^ arr[j];
				arr[i] = arr[i] ^ arr[j];
			}
			return arr;
		}

		long[] uniq(long[] arr) {
			arr = scn.shuffle(arr);
			Arrays.parallelSort(arr);
			long[] rv = new long[arr.length];
			int pos = 0;
			rv[pos++] = arr[0];
			for (int i = 1; i < arr.length; i++) {
				if (arr[i] != arr[i - 1]) {
					rv[pos++] = arr[i];
				}
			}
			return Arrays.copyOf(rv, pos);
		}

		int[] uniq(int[] arr) {
			arr = scn.shuffle(arr);
			Arrays.parallelSort(arr);
			int[] rv = new int[arr.length];
			int pos = 0;
			rv[pos++] = arr[0];
			for (int i = 1; i < arr.length; i++) {
				if (arr[i] != arr[i - 1]) {
					rv[pos++] = arr[i];
				}
			}
			return Arrays.copyOf(rv, pos);
		}

		long[] reverse(long[] arr) {
			int i = 0, j = arr.length - 1;
			while (i < j) {
				arr[i] = arr[i] ^ arr[j];
				arr[j] = arr[i] ^ arr[j];
				arr[i] = arr[i] ^ arr[j];
				i++;
				j--;
			}
			return arr;
		}

		int[] reverse(int[] arr) {
			int i = 0, j = arr.length - 1;
			while (i < j) {
				arr[i] = arr[i] ^ arr[j];
				arr[j] = arr[i] ^ arr[j];
				arr[i] = arr[i] ^ arr[j];
				i++;
				j--;
			}
			return arr;
		}

		long[] compres(long[] arr) {
			int n = arr.length;
			long[] rv = Arrays.copyOf(arr, n);
			rv = uniq(rv);
			for (int i = 0; i < n; i++) {
				arr[i] = Arrays.binarySearch(rv, arr[i]);
			}
			return arr;
		}

		int[] compres(int[] arr) {
			int n = arr.length;
			int[] rv = Arrays.copyOf(arr, n);
			rv = uniq(rv);
			for (int i = 0; i < n; i++) {
				arr[i] = Arrays.binarySearch(rv, arr[i]);
			}
			return arr;
		}

		void deepFillLong(Object array, long val) {
			if (!array.getClass().isArray()) {
				throw new IllegalArgumentException();
			}
			if (array instanceof long[]) {
				long[] intArray = (long[]) array;
				Arrays.fill(intArray, val);
			} else {
				Object[] objArray = (Object[]) array;
				for (Object obj : objArray) {
					deepFillLong(obj, val);
				}
			}
		}

		void deepFillInt(Object array, int val) {
			if (!array.getClass().isArray()) {
				throw new IllegalArgumentException();
			}
			if (array instanceof int[]) {
				int[] intArray = (int[]) array;
				Arrays.fill(intArray, val);
			} else {
				Object[] objArray = (Object[]) array;
				for (Object obj : objArray) {
					deepFillInt(obj, val);
				}
			}
		}

		void tr(Object... o) {
			if (!oj)
				System.out.println(Arrays.deepToString(o));
		}
	}
}
