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 collections import deque
n=int(input())
if n==1:
    print(-1)
else:
    x=list(map(str,range(1,n+1)))
    if len(x)%2==0:
        for i in range(0,len(x),2):
            x[i],x[i+1]=x[i+1],x[i]
        print(' '.join(x))
            
    else:
        # Lfirst=x[:len(x)-1]
        # g=[]
        # g.append(x[-1])
        # for i in Lfirst:
        #     g.append(i)
        # print(' '.join(g))
        print(-1)    
        
        # g=deque(x).rotate(1)
        # g=list(g)
        # # for i in range(1,len(x),2):
        # #     x[i],x[i-1]=x[i-1],x[i]
        # # x[-1],x[-2]=x[-2],x[-1]
        # # print(' '.join(x))
        # print(' '.join(list(g)))