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:
a = int(input())
x = list()
flag =0
j=a
f=0
cnt = 1
if a%2!=0:
	f=1
while(j!=0):
    cnt*=j
    j-=1
for i in range(1,a+1):
    j=i
    cmt = 1
    while(j!=0):
        cmt*=j
        j-=1
    if i != (cnt/cmt):
        x.append(a-i+1)
        flag = 1
if flag==0 or f==1:
    print(-1)
else:
    print(' '.join(str(i) for i in x))