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
# import time
# sys.stdin=open("utest.in","r")
# sys.stdout=open("utest.out","w")

n=int(input())
q=[2 for i in range(n//2)]
u=[2 for i in range((n-3)//2)]
if  n%2==0:
	print(n//2)
	for  i in q:
		print(i,end=" ") 
else:
	print((n-3)//2+1)
	for  i in u:
		print(i,end=" ")
	print(3)