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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;

namespace ABC134
{
    class D
    {
        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());
            int[] a = Console.ReadLine().Split().Select(int.Parse).ToArray();

            int[] b = new int[N + 1];
            for (int i = N; 0 < i; i--)
            {
                int count = 0;
                int j = 1;
                while (i * j <= N)
                {
                    count += b[i * j];
                    j++;
                }

                if (count % 2 != a[i - 1]) { b[i] = 1; }
                else { b[i] = 0; }
            }

            List<int> list = new List<int>();
            int index = 0;
            foreach (var item in b)
            {
                if (item == 1) { list.Add(index); }
                index++;
            }

            Console.WriteLine(list.Count());
            foreach (var item in list)
            {
                Console.Write(item);
                Console.Write(' ');
            }
            if (list.Count != 0) Console.WriteLine();
        }
    }
}