Bachgold Problem

1000ms

262144K

Description:

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.

Sample Input:

Sample Output:

2
2 3

Sample Input:

Sample Output:

3
2 2 2

Informação

Provedor Codeforces

Código CF749A