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A. Perfect Permutation

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputA permutation is a sequence of integers *p*_{1}, *p*_{2}, ..., *p*_{n}, consisting of *n* distinct positive integers, each of them doesn't exceed *n*. Let's denote the *i*-th element of permutation *p* as *p*_{i}. We'll call number *n* the size of permutation *p*_{1}, *p*_{2}, ..., *p*_{n}.

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 *p*_{pi} = *i* and *p*_{i} ≠ *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*, *p*_{1}, *p*_{2}, ..., *p*_{n} — 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

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