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:
from sys import stdin, stdout
import math

n = int(stdin.readline())
if n == 3:
    print(1)
    print(3)
else:
    if n%2 == 0:
        print(n/2)
        print(' '.join('2' for i in range(n/2)))
    else:
        print(n/2)
        s = ' '.join('2' for i in range(n/2-1)) + ' 3'
        print(s)