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

public class Hello
{
    public static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        string[] line = ("0 " + Console.ReadLine().Trim()).Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        getAns(a, n);

    }
    static void getAns(int[] a, int n)
    {
        var b = new int[n + 1];
        var ans = new List<int>();
        for (int i = n; i >= 1; i--)
        {
            if (a[i] != getSum(b, n, i) % 2) { b[i] = 1; ans.Add(i); }
        }
        var ansc = ans.Count();
        Console.WriteLine(ansc);
        if (ansc != 0)
        {
            var ans2 = ans.ToArray();
            Array.Reverse(ans2);
            Console.WriteLine(string.Join(" ", ans2));
        }
    }
    static int getSum(int[] b, int n, int t)
    {
        var sum = 0;
        var t2 = t;
        var p = 2;
        while (t2 <= n)
        {
            sum += b[t2];
            t2 = t * p++;
        }
        return sum;
    }
}