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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 2010-2020 Mike Mirzayanov

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