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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main(void) {
  long i,j,num=0;

  long n;
  scanf("%ld",&n);

  int a[n+1];
  for(i=1;i<=n;i++){
    scanf("%d",&a[i]);
  }

  int ans[n+1];

  for(i=0;i<=n;i++){
    ans[i]=0;
  }

  for(i=n;i>=1;i--){
    for(j=2;i*j<=n;j++){
      if(ans[i*j]==1){
        ans[i]=(ans[i]+1)%2;
      }
    }
    if(ans[i]==a[i]){
    }else{
      ans[i]=(ans[i]+1)%2;
      num++;
    }
  }


  printf("%ld\n",num);
  for(i=1;i<=n;i++){
    if(ans[i]==1){
      printf("%ld ",i);
    }
  }
  printf("\n");

  return 0;
}