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:
from math import sqrt, ceil
n = int(input())
def issimple(n):
    for i in range(2, ceil(sqrt(n))+1):
        if not n%i:
            return False
    return True
if not n%2:
    print(n//2)
    print(' '.join(['2' for i in range(n//2)]))
else:
    if n == 3:
        print(1)
        print('3')
    else:
        print((n-3)//2+1)
        print(' '.join(['2' for i in range((n-3)//2)]), end = ' ')
        print('3')