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.Arrays;
import java.util.Scanner;

public class Main {

    public static void main(String... s) {
        Scanner sc = new Scanner(System.in);
        int size = sc.nextInt();
        boolean possible = true;
        int finalArray[] = new int[size];

        for (int i = 0; i < size; i++) {
            if (finalArray[i] == 0) {
                finalArray[i] = i + 2;
                if(i+1 < finalArray.length) {
                    finalArray[i + 1] = i + 1;
                } else {
                    possible = false;
                    break;
                }
            }
        }
        if(possible) {
            Arrays.stream(finalArray).forEach(num -> {
                System.out.print(num + " ");
            });
        } else {
            System.out.println("-1");
        }
    }

}