PERMU - Permutation
A permutation is a sequence of integers p1, p2 ... pn, consisting of n distinct positive integers, each of which 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
First line will contain number of test case T, followed by T lines.
Each 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 a space.
Example
Input: 3
1
2
4
Output: -1
2 1
2 1 4 3
Added by: | Aradhya |
Date: | 2012-10-12 |
Time limit: | 0.100s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | Rgiit local |