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.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int M = in.nextInt();
		int[] b = new int[M + 1];
		for (int i = 1; i <= M; i++) {
			b[i] = Integer.parseInt(in.next());
		}
		//		boolean isOk = true;
		for (int i = M / 2; i > 0; i--) {
			int sum = 0;
			for (int j = 2; j * i <= M; j++) {
				if (b[j * i] == 1) {
					sum++;
				}
			}
			if (sum % 2 != 0) {
				if (b[i] == 0) {
					b[i] = 1;
				}
			} else {
				if (b[i] == 1) {
					b[i] = 1;
				}
			}
		}
		int count = 0;
		StringBuilder sb = new StringBuilder();
		for (int i = 1; i < b.length; i++) {
			if (b[i] == 1) {
				count++;
				sb.append(b[i]);
				if (i != b.length - 1) {
					sb.append(" ");
				}
			}
		}
		if (sb.length() != 0 && sb.charAt(sb.length() - 1) == ' ') {
			sb.deleteCharAt(sb.length() - 1);
		}
		System.out.println(count);
		if (count != 0) {
			System.out.println(sb.toString());
		}
		in.close();
	}
}