Problem: A permutation is a sequence of integers p1, p2, ..., pn, consisting of n distinct positive integers, each of them doesn't exceed n. Let's denote the i-th element of permutation p as pi. We'll call number n the size of permutation p1, p2, ..., pn.

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 ppi = i and pi ≠ 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, p1, p2, ..., pn — 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 

Solution (in PYTHON3):

Solution:
from math import *
#from math import comb as nCr
import sys
from sys import *
def gI(): return map(int, sys.stdin.readline().strip().split())
def gL(): return list(map(int, sys.stdin.readline().strip().split()))
t=stdin.readline
p=stdout.write
'''
for _ in range(int(t())):
    n=int(t())
    a,b=gI()
    a=gL()
'''
n=int(t())
a=range(n,0,-1)
print('-1' if n%2 else ' '.join(map(str,a)))