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 itertools import product
from math import ceil

def binary_table(string_with_all_characters, length_to_make):
    return [''.join(x) for x in product(string_with_all_characters, repeat=length_to_make)]


def all_possible_substrings(string):
    return [string[i: j] for i in range(len(string)) for j in range(i + 1, len(string) + 1)]


def number_of_substrings(length):
    return int(length * (length + 1) / 2)


def is_prime(num):
    for i in range(2, num):
        if num / i == int(num / i) and num != i:
            return False

    return True


"""for enumeration in range(int(input())):
"""
inp = int(input())
builder = [0] * inp
if inp % 2:
    print(-1)
else:
    for i in range(1, inp + 1):
        builder[-i] = i
    print(*builder)