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:
n=int(input())
if n%2==0 : 
    print(n//2)
    n=n//2
    while n>0 : 
        print(2,end=' ')
        n=n-1
else : 
    print(((n-3)//2)+1)
    print(3,end=' ')
    n=n-3
    n=n//2
    while n>0:
        print(2,end = ' ')
        n=n-1