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:
__author__ = 'Devesh Bajpai'

'''
https://codeforces.com/problemset/problem/749/A

Solution: 
'''


def solve(n):

    result = [2] * (n/2)
    if n % 2 != 0:
        result[(n/2)-1] = 3

    return str(n/2) + "\n" + " ".join(str(elem) for elem in result)


if __name__ == "__main__":

    n = int(raw_input())
    print solve(n)