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 Python (3.4.3) (judge verdict: Wrong Answer)

from collections import deque
import sys
a = int(input())
flags = [int(i) for i in input().split()]

errorend = False
balls = deque()
balling =[]
for i in range(a):
    balls.appendleft(0)

for i in reversed(range(0, a)):
    temp = 0
    for j in range(i, a, i + 1):
        temp += balls[j]
    if flags[i] == 1:
        if temp % 2 == 0:
            balls[i] = 1
            balling.append(i + 1)
        else:
            balls[i] = 0
    else:
        if temp % 2 == 0:
            balls[i] = 0
        else:
            balls[i] = 1
            balling.append(i + 1)

if balls[0] == 0:
    if flags[0] == 1:
        print('-1')
        sys.exit()
if flags[0] == 1:
    if flags[0] != 1:
        print('-1')
        sys.exit()

m = balls.count(1)
print(m)
if m != 0:
    for i in balling:
      print(i, end=' ')