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())

#sieve = list(range(2, n + 1))
#
#num2remove = set()
#for i in range(len(sieve)):
#    for j in range(i+1):
#        num2remove.add(sieve[i] * sieve[j])
#    i += 1
#    
#sieve = [e for e in sieve if e not in num2remove]

res = []

if n == 2:
    print(1)
    print(2)
elif n == 3:
    print(1)
    print(3)
else:
    if n % 2 == 0:
        res = [str(e) for e in [2] * (n // 2)]
    else:
        res = [str(e) for e in [2] * (n // 2 - 1) + [3]]

    print(len(res))
    print(' '.join(res))