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())
d=2
u=1
dd=[]
uu=[]
ue=[]

t=False
if a==1:
    print("-1",end="")
else:
    for i in range (1,a,1):
        dd.append(d)
        d+=2
        dd.append(u)
        u+=2
    for num in dd:
        if num<=a:
            uu.append(num)
    j=0
    for num2 in uu:
        if a==uu[-1]:
            print("-1")
            break
        else:
            t=True
        
if t==True:
        ue=" ".join(map(str,uu))
        print(ue)