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 CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int main() {
  int a[100000];
  int j = 0;
  int n;
  cin >> n;
  int n1 = n;
  if (!(n & 1)) {
    while (n > 0) {
      a[j++] = 2;
      n -= 2;
    }
  } else {
    n--;
    while (n > 0) {
      a[j++] = 2;
      n -= 2;
    }
  }
  if (n1 & 1) {
    a[j - 1] = 3;
  }
  cout << j << endl;
  for (int i = 0; i < j; i++) {
    cout << a[i] << " ";
  }
  cout << endl;
  return 0;
}