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:
# -*- coding:utf-8 -*-


def some_func():
    """
    """

    n =input()

    if n%2:
        print (n-1)/2
        for v in range((n-3)/2):
            print 2,
        print 3
    else:
        print n/2
        for v in range((n-2)/2):
            print 2,
        print 2





if __name__ == '__main__':
    some_func()