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 perfectpermutation {
    public static void main(String[] args) {
        Scanner scn = new Scanner(System.in);
        int N = scn.nextInt();
        if (N == 1) {
            System.out.println(-1);
        } else {
            int flag = 0;
            int[] arr = new int[N];
            int[] dp = new int[N + 1];
            for (int i = 0; i < N; i++) {
                if (arr[i] != 0)
                    continue;
                for (int j = 1; j <= N; j++) {
                    if (j == i + 1)
                        continue;
                    if (dp[j] == 0) {
                        arr[i] = j;
                        dp[j]++;
                        break;
                    }
                }
                if (arr[i] == 0) {
                    System.out.println(-1);
                    flag++;
                    break;
                }
                arr[arr[i] - 1] = i + 1;
                dp[i + 1]++;
            }
            if (flag == 0) {
                for (int i = 0; i < N; i++)
                    System.out.print(arr[i] + " ");
                System.out.println();
            }

        }
    }
}