<? echo $row['title']." - ".$MSG_PROBLEM."

Time Limit: 2 sec / Memory Limit: 1024 MB

Score :

300

points

We define sequences

S_n

as follows.

$S_1$ is a sequence of length $1$ containing a single $1$ .
$S_n$ ( $n$ is an integer greater than or equal to $2$ ) is a sequence obtained by concatenating $S_{n-1}$ , $n$ , $S_{n-1}$ in this order.

For example,

S_2

and

S_3

is defined as follows.

$S_2$ is a concatenation of $S_1$ , $2$ , and $S_1$ , in this order, so it is $1, 2, 1$ .
$S_3$ is a concatenation of $S_2$ , $3$ , and $S_2$ , in this order, so it is $1, 2, 1, 3, 1, 2, 1$ .

Given

N

, print the entire sequence

S_N

Input is given from Standard Input in the following format:

$N$

S_N

, with spaces in between.