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"
	"math"
	"os"
	"strconv"
)

func getScanner(fp io.Reader) *bufio.Scanner {
	sc := bufio.NewScanner(fp)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 500001), 500000)
	return sc
}

func getHugeScanner(fp io.Reader, size int) *bufio.Scanner {
	sc := bufio.NewScanner(fp)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, size), size)
	return sc
}

func getNextString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func getNextInt(sc *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(sc))
	return i
}

func getNextInt64(sc *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(sc), 10, 64)
	return i
}
func getNextFloat64(sc *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(sc), 64)
	return i
}

func Divisor(x int) []int {
	ret := make([]int, 0)
	for i := 1; i < int(math.Sqrt(float64(x))) + 1; i++ {
		if x % i == 0 {
			ret = append(ret, i)
			if x / i != i {
				ret = append(ret, x / i)
			}
		}
	}
	return ret
}

func Solve(stdin io.Reader, stdout io.Writer) {
	sc := getScanner(stdin)

	n := getNextInt(sc)

	a := make([]int, n + 1)
	b := make(map[int]int)

	for i := 1; i <= n; i++ {
		a[i] = getNextInt(sc)
	}

	m := 0

	for i := n; i > 0; i-- {
		if a[i] == 0 {
			continue
		}
		divs := Divisor(i)
		for _, v := range divs {
			m++
			b[v]++
		}
	}
	_, _ = fmt.Fprintf(stdout, "%v\n", m)
	for k, v := range b {
		for i := 0; i < v; i++ {
			_, _ = fmt.Fprintf(stdout, "%v ", k)
		}
	}
}

func main() {
	Solve(os.Stdin, os.Stdout)
	return
}