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:
def ii(): return int(input())
def fi(): return float(input())
def si(): return input()
def mi(): return map(int,input().split())
def li(): return list(mi())

import math
 
n=ii()
if n%2==0:
    a=n//2 
    print(a)
    print((a-1)*"2 "+1*"2")
else:
    a=(n-3)//2 
    print(a+1)
    print(a*"2 "+"3")