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 PYTHON3):

Solution:
import sys, os.path
if(os.path.exists("in.txt")):
    sys.stdin = open("in.txt","r")
    sys.stdout = open("out.txt","w")

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

if n % 2 == 0:
	print(a)
	for i in range(a):
		print(2, end = " ")
else:
	print(a)
	for i in range(a - 1):
		print(2, end = " ")
	print(3)