package main

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

func isPrime(n int) bool {
	if n < 2 {
		return false
	}
	if n == 2 || n == 3 {
		return true
	}
	if n%2 == 0 || n%3 == 0 {
		return false
	}
	for i := 5; i*i <= n; i += 6 {
		if n%i == 0 || n%(i+2) == 0 {
			return false
		}
	}
	return true
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)

	if !scanner.Scan() {
		return
	}
	n, _ := strconv.Atoi(scanner.Text())

	a := make([]int, n)
	ones := 0
	for i := 0; i < n; i++ {
		scanner.Scan()
		a[i], _ = strconv.Atoi(scanner.Text())
		if a[i] == 1 {
			ones++
		}
	}

	ans1 := []int{}
	if ones > 0 {
		for i := 0; i < ones; i++ {
			ans1 = append(ans1, 1)
		}
		for _, x := range a {
			if x != 1 && isPrime(x+1) {
				ans1 = append(ans1, x)
				break
			}
		}
	}

	ans2 := []int{}
	for i := 0; i < n; i++ {
		for j := i + 1; j < n; j++ {
			if isPrime(a[i] + a[j]) {
				ans2 = []int{a[i], a[j]}
				break
			}
		}
		if len(ans2) > 0 {
			break
		}
	}

	ans3 := []int{a[0]}

	res := ans1
	if len(ans2) > len(res) {
		res = ans2
	}
	if len(ans3) > len(res) {
		res = ans3
	}

	fmt.Println(len(res))
	strRes := make([]string, len(res))
	for i, x := range res {
		strRes[i] = strconv.Itoa(x)
	}
	fmt.Println(strings.Join(strRes, " "))
}