Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ACM-ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

No tag edit access

D. Optimal Number Permutation

time limit per test

1 secondmemory limit per test

256 megabytesinput

standard inputoutput

standard outputYou have array *a* that contains all integers from 1 to *n* twice. You can arbitrary permute any numbers in *a*.

Let number *i* be in positions *x*_{i}, *y*_{i} (*x*_{i} < *y*_{i}) in the permuted array *a*. Let's define the value *d*_{i} = *y*_{i} - *x*_{i} — the distance between the positions of the number *i*. Permute the numbers in array *a* to minimize the value of the sum .

Input

The only line contains integer *n* (1 ≤ *n* ≤ 5·10^{5}).

Output

Print 2*n* integers — the permuted array *a* that minimizes the value of the sum *s*.

Examples

Input

2

Output

1 1 2 2

Input

1

Output

1 1

Codeforces (c) Copyright 2010-2017 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Mar/26/2017 19:55:40 (c2).

Desktop version, switch to mobile version.
User lists

Name |
---|