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: Accepted)

n = int(input())
ai = list(map(int, input().split()))

#print(ai)
dai={}
dbi={}
for i in range(1, n+1):
    dai.setdefault(i, ai[i-1])
    dbi.setdefault(i, 0)

#print(dai)
#print(dbi)

anssum=0
ans=[]
for i in range(1, n+1)[::-1]:
    #print(i)
    tmp=0
    for j in range(2, n+1):
        check=i*j
        if check <= n:
            tmp = tmp + dbi[check]
        else:
            break
    tmp = tmp%2
    #print(str(tmp) + ", " + str(dai[i]))
    if tmp != dai[i]:
        dbi[i]=1
        anssum=anssum+1
        ans.append(i)

#print(dbi)
print(anssum)
if anssum != 0:
    print(" ".join(map(str, reversed(ans))))