#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j, k;
  cin >> n;
  if (n == 3)
    cout << 1 << endl << 3;
  else {
    k = 0;
    vector<int> v;
    if (n & 1) {
      while (n > 3) {
        v.push_back(2);
        n -= 2;
        k++;
      }
      v.push_back(3);
      k++;
    } else {
      while (n) {
        v.push_back(2);
        n -= 2;
        k++;
      }
    }
    cout << k << endl;
    for (i = 0; i < v.size(); i++) cout << v[i] << " ";
  }
  return 0;
}

### Prompt

Construct a cpp code solution to the problem outlined:

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

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j, k;
  cin >> n;
  if (n == 3)
    cout << 1 << endl << 3;
  else {
    k = 0;
    vector<int> v;
    if (n & 1) {
      while (n > 3) {
        v.push_back(2);
        n -= 2;
        k++;
      }
      v.push_back(3);
      k++;
    } else {
      while (n) {
        v.push_back(2);
        n -= 2;
        k++;
      }
    }
    cout << k << endl;
    for (i = 0; i < v.size(); i++) cout << v[i] << " ";
  }
  return 0;
}

```