Problem:
Score : 400 points

Problem Statement

There are N empty boxes arranged in a row from left to right.
The integer i is written on the i-th box from the left (1 \leq i \leq N).

For each of these boxes, Snuke can choose either to put a ball in it or to put nothing in it.

We say a set of choices to put a ball or not in the boxes is good when the following condition is satisfied:

For every integer i between 1 and N (inclusive), the total number of balls contained in the boxes with multiples of i written on them is congruent to a_i modulo 2.

Does there exist a good set of choices? If the answer is yes, find one good set of choices.

Constraints

All values in input are integers.

1 \leq N \leq 2 \times 10^5

a_i is 0 or 1.

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

If a good set of choices does not exist, print -1.

If a good set of choices exists, print one such set of choices in the following format:

M
b_1 b_2 ... b_M

where M denotes the number of boxes that will contain a ball, and b_1,\ b_2,\ ...,\ b_M are the integers written on these boxes, in any order.

Sample Input 1

3
1 0 0

Sample Output 1

1
1

Consider putting a ball only in the box with 1 written on it.

There are three boxes with multiples of 1 written on them: the boxes with 1, 2, and 3. The total number of balls contained in these boxes is 1.

There is only one box with a multiple of 2 written on it: the box with 2. The total number of balls contained in these boxes is 0.

There is only one box with a multiple of 3 written on it: the box with 3. The total number of balls contained in these boxes is 0.

Thus, the condition is satisfied, so this set of choices is good.

Sample Input 2

5
0 0 0 0 0

Sample Output 2

0

Putting nothing in the boxes can be a good set of choices.

Solution in PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php

while ($line = fgets(STDIN)) {
    $tmp[] = trim($line);
}

$n = $tmp[0];
$as = explode(" ", $tmp[1]);

$result = array();
$count = 0;

for ($i = count($as) - 1; $i >= 0; $i--) {
    $cnt = 0;
    for ($j = $i; $j < count($as); $j += ($i + 1)) {
        if (isset($result[$j]) && $result[$j] == 1) {
            $cnt++;
        }
    }
    if($cnt == $as[$i] % 2){
        $result[$i] = 0;
    }elseif($cnt == ($as[$i] % 2) - 1){
        $result[$i] = 1;
        $count++;
    }else{
        $result = false;
        break;
    }
}

if($result === false){
    echo "-1";
}else{
    echo $count ."\n";
    foreach ($result as $key => $r){
        if($r == 1){
            echo ($key + 1) ." ";
        }
    }
}