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A10714 | $Bachgold Problem$

时间限制1s

内存限制256MB

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题目描述

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 $k$ .

输入格式

The only line of the input contains a single integer $n$ ( $2<=n<=100000$ ).

输出格式

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.

输入输出样例

输入 #1

输出 #1

2
2 3

输入 #2

输出 #2

3
2 2 2

C++ 编辑器

输入

输出