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 math,sys,re,itertools,pprint,collections,copy
rs,ri,rai,raf=input,lambda:int(input()),lambda:list(map(int, input().split())),lambda:list(map(float, input().split()))

n = ri()

if n % 2 == 0:
    res = [2] * (n//2)
else:
    k = n - 3
    res = [3] + ([2] * (k//2))

print(len(res))
print(" ".join(map(str, res)))