Polo the Penguin and XOR operation

2000ms

262144K

Description:

Little penguin Polo likes permutations. But most of all he likes permutations of integers from 0 to n, inclusive.

For permutation p = p₀, p₁, ..., p_n, Polo has defined its beauty — number $\text{[math]}$ .

Expression $\text{[math]}$ means applying the operation of bitwise excluding "OR" to numbers x and y. This operation exists in all modern programming languages, for example, in language C++ and Java it is represented as "^" and in Pascal — as "xor".

Help him find among all permutations of integers from 0 to n the permutation with the maximum beauty.

Input:

The single line contains a positive integer n (1 ≤ n ≤ 10⁶).

Output:

In the first line print integer m the maximum possible beauty. In the second line print any permutation of integers from 0 to n with the beauty equal to m.

If there are several suitable permutations, you are allowed to print any of them.

Sample Input:

Sample Output:

20
0 2 1 4 3

Informação

Provedor Codeforces

Código CF288C