Loại các phần tử ở chỉ số chẵn (Remove Elements at Even Indices)

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem

Given an integer array $a_0,a_1,\ldots,a_{n-1}$ using 0-based indexing.

Remove every element whose original index is even, i.e. every $a_i$ satisfying

Elements at original odd indices keep their relative order. Thus the result is

up to the last valid index below $n$.

Print the new size and the resulting array.

Input

The first line contains integer $n$. The second line contains exactly $n$ integers $a_0,a_1,\ldots,a_{n-1}$.

Output

Print the new size $m=\lfloor n/2 floor$ on the first line. If $m>0$, print the elements from original odd indices on the second line.

Subtask

Subtask 1 (100 points): $1\le n\le2\cdot10^5$; $|a_i|\le10^9$.

Example

Input

7
10 20 30 40 50 60 70

Output

3
20 40 60

Explanation

The original odd indices are $1,3,5$, containing $20,40,60$. Indices are interpreted in the original array, not recomputed after each deletion.