CF622D.Optimal Number Permutation

You 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 .

The only line contains integer $n$ ( $1<=n<=5·10^{5}$ ).

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