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 Ruby (2.3.3) (judge verdict: Accepted)

N = gets.chomp.to_i
arr = gets.chomp.split(" ").map(&:to_i)
# p arr
ans = Array.new(N)


(N-1).downto(0) do |n|
    box_num = n+1
    multi_arr = box_num.step(N,box_num)
    # p multi_arr
    # p "multi"
    sum = 0
    multi_arr.reverse_each do |i|
        # p arr[i-1]
        if not ans[i-1].nil?
            sum += ans[i-1]
        else
            ans[i-1] = (sum % 2) ^ arr[i-1]
        end
    end
end
# p ans
nums = []
b_n = 1
m = 0
ans.each do |n|
    if n == 1
        nums << b_n
        m+=1
    end
    b_n+=1
end
puts m
if not m == 0
    puts nums.join(" ")
end