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 Go (1.6) (judge verdict: Wrong Answer)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}

func main() {
	var n, m int
	var a, b []int

	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		h := nextInt()
		a = append(a, h)
	}

	for i := len(a) - 1; i >= 0; i-- {
		var sum int
		for j := 2; (i+1)*j < len(a); {
			if a[(i+1)*j] == 1 {
				sum++
			}
			j++
		}
		switch a[i] {
		case 0:
			if sum%2 == 1 {
				b = append([]int{i + 1}, b...)
				m++
			}
		case 1:
			if sum%2 == 0 {
				b = append([]int{i + 1}, b...)
				m++
			}
		}

	}
	fmt.Println(m)
	for i, h := range b {
		if i == len(b)-1 {
			fmt.Printf("%v\n", h)
		} else {
			fmt.Printf("%v ", h)
		}
	}

}