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 $\frac{n}{2}$ the following equation is true: $a_i + a_{n - i + 1} = x$, where $x$ should be the same for all $\frac{n}{2}$ pairs of elements. 
You have to answer $t$ independent test cases.
-----Input-----
The first line of the input contains one integer $t$ ($1 \le t \le 10^4$) — the number of test cases. Then $t$ test cases follow.
The first line of the test case contains two integers $n$ and $k$ ($2 \le n \le 2 \cdot 10^5, 1 \le k \le 2 \cdot 10^5$) — 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 $a_1, a_2, \dots, a_n$ ($1 \le a_i \le k$), 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 $2 \cdot 10^5$ ($\sum n \le 2 \cdot 10^5$, $\sum k \le 2 \cdot 10^5$).
-----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
A = [0 for x in range(400005)]
t = int(input())
def mymin(a,b):
    if(a<b):
        return a
    else:
        return b

def mymax(a,b):
    if(a>b):
        return a
    else:
        return b

for tests in range(t):
    [n,k] = input().split()
    n = int(n)
    k = int(k)
    B = input().split()
    for i in range(2,(2*k)+1):
        A[i] = 0
    n2 = int(n/2)
    for i in range(n2):
        B[i] = int(B[i])
        B[n-1-i] = int(B[n-1-i])
        mi = mymin(B[i],B[n-1-i])
        ma = mymax(B[i],B[n-1-i])
        A[2] += 2
        A[mi+1] -= 1
        A[mi+ma] -= 1
        if(mi+ma+1 <= 2*k):
            A[mi+ma+1] +=1
        if(ma+k+1 <= 2*k):
            A[ma+k+1] +=1
    ans = n
    for i in range(2,(2*k)+1):
        A[i] += A[i-1]
        if(A[i]<ans):
            ans = A[i]
    print(ans)

A = [0 for x in range(400005)]
t = int(input())
def mymin(a,b):
    if(a<b):
        return a
    else:
        return b

def mymax(a,b):
    if(a>b):
        return a
    else:
        return b

for tests in range(t):
    [n,k] = input().split()
    n = int(n)
    k = int(k)
    B = input().split()
    for i in range(2,(2*k)+1):
        A[i] = 0
    n2 = int(n/2)
    for i in range(n2):
        B[i] = int(B[i])
        B[n-1-i] = int(B[n-1-i])
        mi = mymin(B[i],B[n-1-i])
        ma = mymax(B[i],B[n-1-i])
        A[2] += 2
        A[mi+1] -= 1
        A[mi+ma] -= 1
        if(mi+ma+1 <= 2*k):
            A[mi+ma+1] +=1
        if(ma+k+1 <= 2*k):
            A[ma+k+1] +=1
    ans = n
    for i in range(2,(2*k)+1):
        A[i] += A[i-1]
        if(A[i]<ans):
            ans = A[i]
    print(ans)
