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:
def main():
    n = int(input())
    m, st = solve(n)
    print(m)
    print(st)
def solve(n):
    m = 0
    if not n % 2:
        m = n // 2
        st = '2 '*m
        st = st[:-1]
    else:
        m = ((n-3) // 2) + 1
        st = '2 '*(m-1) + '3 '
        st = st[:-1]
    return m, st
main()