A permutation is a sequence of integers p_1, p_2, ..., p_{n}, consisting of n distinct positive integers, each of them doesn't exceed n. Let's denote the i-th element of permutation p as p_{i}. We'll call number n the size of permutation p_1, p_2, ..., p_{n}.

Nickolas adores permutations. He likes some permutations more than the others. He calls such permutations perfect. A perfect permutation is such permutation p that for any i (1 ≤ i ≤ n) (n is the permutation size) the following equations hold p_{p}_{i} = i and p_{i} ≠ i. Nickolas asks you to print any perfect permutation of size n for the given n.


-----Input-----

A single line contains a single integer n (1 ≤ n ≤ 100) — the permutation size.


-----Output-----

If a perfect permutation of size n doesn't exist, print a single integer -1. Otherwise print n distinct integers from 1 to n, p_1, p_2, ..., p_{n} — permutation p, that is perfect. Separate printed numbers by whitespaces.


-----Examples-----
Input
1

Output
-1

Input
2

Output
2 1 

Input
4

Output
2 1 4 3

Difficulty: interview

Starter code:

Solutions:
n=int(input())

if(n%2==1):
    print(-1)

else:
    L=list(range(1,n+1))
    for i in range(0,n,2):
        t=L[i]
        L[i]=L[i+1]
        L[i+1]=t
    for i in range(n-1):
        print(L[i],end=" ")
    print(L[-1])


#import sys
#my_file = sys.stdin
#my_file = open("input.txt", "r")
num = int(input())
a = list(range(1,num+1))
if num%2!=0:
    print('-1')
else:
    for i in range(num)[::2]:
        a[i],a[i+1] = a[i+1], a[i]
    print(' '.join(map(str, a)))

n = int(input())
if n % 2 == 0:
    for i in range(1, n // 2 + 1): print(2 * i, 2 * i - 1, end = ' ')
else: print(-1)

3

def readln(): return tuple(map(int, input().split()))

n, = readln()
if n % 2:
    print(-1)
else:
    for i in range(0, n, 2):
        print(i + 2, i + 1, end=' ')
    print()


n = int(input())
if n%2==1:
    print("-1")
else:
    for i in range(1,n,2):
        print(i+1,i,sep=" ",end=" ")


def main() -> int:
    n = int(input())

    if n % 2 != 0 or n < 2:
        print(-1)
    else:
        result = [i for i in range(n)]
        result[0::2] = result[2::2] + [n]
        print(' '.join(str(i) for i in result))

    return 0


def __starting_point():
    main()
__starting_point()

n = int(input())
if n % 2:
    print(-1)
else:
    print(*list(range(n, 0, -1)))

sa=int(input())
if sa%2==1:
    print(-1)
else:
    ans=''
    for x in range(1, int(sa/2+1)):
        ans+=str(2* x)
        ans+=' '
        ans+=str(2*x-1)
        ans+=' '
    print(ans.strip())


a=int(input())
if a%2==1:print(-1)
else:
 i=-1
 while i<a-1:
  i=i+3
  print(i,end=' ')
  i=i-1
  print(i,end=' ')

n = int(input())
if n % 2 != 0:
    print(-1)
else:
    out = [0]*n
    t = True
    for i in range(n):
        if t:
            out[i+1] = i+1
            t = False
        else:
            out[i-1] = i+1
            t = True
    for i in range(n):
        print(out[i],end = " ")


n = int(input())
i = 0
if (n//2)==(n/2):
    while i < n:
        i=i+2
        print(i,i-1, end=" ")
else: print('-1')


n = int(input())
if n % 2 == 0:
    print(' '.join(map(str, [x for y in zip(range(2, n + 1, 2), range(1, n + 1, 2)) for x in y])))
else:
    print(-1)

n = int(input())

if n % 2 == 1:
	print(-1)
else:
	arr = []
	for i in range(1,n+1,2):
		arr.append(i+1)
		arr.append(i)
	print(" ".join(map(str,arr)))

import sys

n = int(sys.stdin.readline())

result = []
if(n % 2 == 0):
    for i in range(1, int(n / 2) + 1):
        t = i * 2
        result.append(str(t))
        result.append(str(t - 1))
    print(" ".join(result))
else:
    print(-1)


n=int(input())

if n%2==1:print(-1)
else:
    for i in range(n):
        if i%2==0:print(i+2,end=" ")
        else:print(i,end=" ")


n = int(input())
if n % 2:
	print('-1')
else:
	print(' '.join(str(x + 2 - x % 2 * 2) for x in range(n)))


def main():
    n = int(input())
    if n & 1:
        return -1,
    return list(range(n, 0, -1))


print(*main())

a=int(input())

if a%2==1:
   print(-1)

else:
   l=[i+1 for i in range(a)]
   
   s=str(l[1])+" "+str(l[0])
   for k in range(1,a//2):
      l[2*k],l[2*k+1]=l[2*k+1],l[2*k]
      s=s+" "+str(l[2*k])+" "+str(l[2*k+1])
   print(s)


# coding: utf-8
n = int(input())
if n%2==1:
    print(-1)
else:
    print(' '.join([str(i+1) if i%2==1 else str(i-1) for i in range(1,n+1)]))


n=int(input())
if n%2==1:
    print(-1)
else :
    a=['0']*n
    for i in range(n):
        a[i]=str(n-i)
    print(' '.join(a))


from fileinput import *

for line in input():
    if lineno() == 1:
        n = int(line.strip())

if n % 2 == 0:
    li = [i + 1 for i in range(n)]
    li[::2], li[1::2] = li[1::2], li[::2]
    print(''.join([str(num) + ' ' for num in li]))
else:
    print('-1')


n = int(input())
if n % 2:
    print(-1)
else:
    arr = list(range(1, n + 1))
    for i in range(0, n, 2):
        arr[i], arr[i + 1] = arr[i + 1], arr[i]
    print(*arr)


n = int(input())

p = list(range(1, n+1))

if ((n % 2) == 0):
	lista = ""
	for i in range(0, n, 2):
		tmp = p[i+1]
		p[i+1] = p[i]
		p[i] = tmp
	for item in p:
		lista += (str(item)+" ")
	print (lista)
else:
	print(-1)



n = int(input())

p = list(range(1, n+1))

if ((n % 2) == 0):
	lista = ""
	for i in range(0, n, 2):
		tmp = p[i+1]
		p[i+1] = p[i]
		p[i] = tmp
	for item in p:
		lista += (str(item)+" ")
	print (lista)
else:
	print(-1)



n = int(input())

p = list(range(1, n+1))

if ((n % 2) == 0):
	lista = ""
	for i in range(0, n, 2):
		tmp = p[i+1]
		p[i+1] = p[i]
		p[i] = tmp
	for item in p:
		lista += (str(item)+" ")
	print (lista)
else:
	print(-1)