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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] array = new int[n];
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
        
        int count = 0;
        int[] tmp = new int[n];
        for (int i = n; i >= 1; i--) {
            if (array[i-1] == 0) {
                if (tmp[i-1] % 2 == 0) {
                    
                } else {
                    List<Long> list = divisorList(i);
                    for (long num : list) {
                        tmp[(int)num-1]++;
                    }
                    count++;
                }
            } else {
                if (tmp[i-1] % 2 == 0) {
                    List<Long> list = divisorList(i);
                    for (long num : list) {
                        tmp[(int)num-1]++;
                    }
                    count++;
                } else {
                    
                }
            }
        }
        
        System.out.println(count);
        if (count == 0) return;
        for (int i = 0; i < n; i++) {
            if (tmp[i] % 2 == 0) continue; 
            System.out.print(i+1);
            if (i != n - 1) {
                System.out.print(" ");
            }
        }
        System.out.println();
    }
    
    public static List<Long> divisorList(long n) {
        List<Long> res = new ArrayList<Long>();
        for (long i = 1; i * i <= n; i++) {
            if (n % i == 0) {
                res.add(i);
                
                long j = n / i;
                if (j != i) {
                    res.add(j);
                }
            }
        }
        res.sort(Comparator.naturalOrder());
        
        return res;
    }
}