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 PYTHON):

Solution:
# coding:utf-8

n = int(input())
x = n/2

def print_ans(x, is_o) :
	print x
	if is_o :
		x -= 1
	for i in xrange(0, x) :
		if i == x - 1 and not is_o :
			print 2
		else :
			print 2, 
	if is_o :
		print 3

print_ans(x, (n&1) == 1)