Problem: Bachgold problem is very easy to formulate. Given a positive integer n represent it as a sum of maximum possible number of prime numbers. One can prove that such representation exists for any integer greater than 1.

Recall that integer k is called prime if it is greater than 1 and has exactly two positive integer divisors — 1 and k. 

Input

The only line of the input contains a single integer n (2 ≤ n ≤ 100 000).

Output

The first line of the output contains a single integer k — maximum possible number of primes in representation.

The second line should contain k primes with their sum equal to n. You can print them in any order. If there are several optimal solution, print any of them.

Examples

Input

5


Output

2
2 3


Input

6


Output

3
2 2 2

Solution (in JAVA):

Solution:
import java.util.*;
public class Main {
	
	public static void main(String[] args)
	{
		Scanner in = new Scanner(System.in);
		
		long  n, m, sum=0;
		n=in.nextInt();
		solve(n);
	}
	private static void solve(long n)
	{
		System.out.println(n/2);
		while(n>3){
			System.out.print(2+" ");
			n-=2;
		}
		System.out.println(n);
	}
}