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:
r = lambda : map(int, raw_input().split())
n = r()[0]
#a = r()
#s = raw_input()
if n %2 == 0 :
    print n/2
    for i in xrange(n/2):
        print 2, 
else :
    n -= 3
    print (n/2 + 1)
    for i in xrange(n/2):
        print 2, 
    print 3