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:
import fileinput

for line in fileinput.input():
  n = int(line) 
  
arr =[]

if n%2 != 0:
  n -= 3
  arr.append(3)
  
while n > 2:
  n -= 2
  arr.append(2)
  
if n > 0: 
  arr.append(n)
  
print(len(arr))
print(' '.join(str(x) for x in arr[::-1]))