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:
"""
https://codeforces.com/problemset/problem/749/A
"""

n = int(input())


if n%2 == 0:
    print(int(n/2))
    s = ""
    for _ in range(int(n/2)):
        s += "2 "
    print(s[:-1])

else:
    print(int((n-3)/2)+1)    
    s = ""
    for _ in range(int((n-3)/2)):
        s += "2 "
    s += "3 "    
    print(s[:-1])