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"
	"io"
	"os"
	"strconv"
)

var (
	readString func() string
	readBytes  func() []byte
)

func init() {
	readString, readBytes = newReadString(os.Stdin)
}

func newReadString(ior io.Reader) (func() string, func() []byte) {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	f1 := func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
	f2 := func() []byte {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Bytes()
	}
	return f1, f2
}

func readInt() int {
	return int(readInt64())
}

func readInt64() int64 {
	i, err := strconv.ParseInt(readString(), 10, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func readFloat64() float64 {
	f, err := strconv.ParseFloat(readString(), 64)
	if err != nil {
		panic(err.Error())
	}
	return f
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func minInt64(a, b int64) int64 {
	if a < b {
		return a
	}
	return b
}

func maxInt64(a, b int64) int64 {
	if a > b {
		return a
	}
	return b
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

func absInt64(a int64) int64 {
	if a < 0 {
		return -a
	}
	return a
}

func sum(a []int) int {
	var ret int
	for i := range a {
		ret += a[i]
	}
	return ret
}

func sumInt64(a []int64) int64 {
	var ret int64
	for i := range a {
		ret += a[i]
	}
	return ret
}

func sumFloat64(a []float64) float64 {
	var ret float64
	for i := range a {
		ret += a[i]
	}
	return ret
}

func gcdInt64(m, n int64) int64 {
	for m%n != 0 {
		m, n = n, m%n
	}
	return n
}

func lcmInt64(m, n int64) int64 {
	return m / gcdInt64(m, n) * n
}

// sort ------------------------------------------------------------

type int64Array []int64

func (s int64Array) Len() int           { return len(s) }
func (s int64Array) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
func (s int64Array) Less(i, j int) bool { return s[i] < s[j] }

type xxx struct {
	x int
}

type sortArray []xxx

func (s sortArray) Len() int           { return len(s) }
func (s sortArray) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
func (s sortArray) Less(i, j int) bool { return s[i].x < s[j].x }

// -----------------------------------------------------------------

func main() {
	n := readInt()
	a := make([]int, n)
	x := make([]int, n)
	ans := make([]int, 0, n)
	for i := range a {
		a[i] = readInt()
	}

	for i := n - 1; i >= 0; i-- {
		j := i + i + 1
		for j < n {
			x[i] = (x[i] + x[j]) % 2
			j += i + 1
		}
		if x[i]%2 != a[i] {
			x[i]++
			ans = append(ans, i+1)
		}
	}

	fmt.Println(len(ans))
	for i := range ans {
		fmt.Print(ans[len(ans)-1-i], " ")
	}
}