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 Prime(n):
    flag = 1
    for i in range(2, n // 2 + 1):
        if n % i == 0:
            flag = 0
            break
    if flag:
        return True
    else:
        return False
n = int(input())
k = 0
L = []
while n > 0:
    if n > 3 or n == 2:
        k += 1
        L.append(2)
        n -= 2
    elif n == 3:
        k += 1
        L.append(3)
        n -= 3
print(k)
for i in range(len(L)):
    print(L[i], end=" ")