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 JAVA):

Solution:
import java.util.*;
public class PracticeCF {

	public static void main(String[] args) {
		 Scanner sc=new Scanner(System.in);
		    int n=sc.nextInt();
		    if(n%2!=0)
		    	System.out.println("-1");
		    else
		    {
		    	int y=2,x=0;
		    	System.out.print("2"+" ");
		    	for(int i=1;i<n;i++)
		    	{
		    		if(x==0)
		    		{
		    			y=y-1;
		    			System.out.print(y+" ");
		    			x=1;
		    		}
		    		else
		    		{
		    			y=y+3;
		    			System.out.print(y+" ");
		    			x=0;
		    		}
		    	}
		    }    
	}
}