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:
import sys
input = sys.stdin.readline


def inp():
    return(int(input()))


def inlt():
    return(list(map(int, input().split())))


def insr():
    s = input()
    return(list(s[:len(s) - 1]))


def invr():
    return(map(int, input().split()))


def foo():
    n = inp()
    print(n//2)
    if n % 2 == 0:
        for i in range(n//2):
            print(2, end=" ")
    else:
        for i in range((n//2)-1):
            print(2, end=" ")
        print(3)


if __name__ == '__main__':
    foo()