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:
z=int(input())
if z%2==0:
    x=[]
    for i in range(z):
        x.append(i+1)
    d=[]
    f=[]
    x.reverse()
    for i in x:
        f.append(i)
        if len(f)==2:
            d.append(f)
            f=[]
    e=d[-1]
    d.reverse()
    q=True
    for i in range(1,len(d)):
        e+=d[i]

    for o in range(z):
        a=x[i]
        if x[a-1]!=i+1:
            q=False
    if q :
        for i in e:
            print(end=str(i)+" ")
    else:
        print(-1)
else:
    print(-1)