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;
const long long mod = 1e9 + 7;
const long long MAX = 1e6 + 10;
long long a[100005];
int main() {
  long long n, k, m, sum, t, len;
  string s, d;
  while (cin >> n) {
    int flag = 1;
    sum = 0;
    if (n % 2 == 0) {
      cout << n / 2 << endl;
      for (long long i = (1); i <= (n / 2); ++i) cout << "2" << ' ';
      cout << endl;
    } else {
      cout << (n - 3) / 2 + 1 << endl;
      for (long long i = (1); i <= ((n - 3) / 2); ++i) cout << "2" << ' ';
      cout << "3" << endl;
    }
  }
  return 0;
}