#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <array>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

void findPrime(int N, vector<bool>& isPrime)
{
    isPrime.assign(N+1, true);
    isPrime[0] = isPrime[1] = false;
    for(int i=2; i*i<=N; i++){
        if(isPrime[i]){
            for(int j=i; i*j<=N; j++){
                isPrime[i*j] = false;
            }
        }
    }
}

const int MAX = 1000000;

int main()
{
    vector<bool> isPrime;
    findPrime(2*MAX, isPrime);

    int k;
    cin >> k;

    int n = 2;
    while(n * (n - 1) / 2 + 3 * n <= k)
        ++ n;
    -- n;

    vector<int> v(n, 1);
    v.push_back(2);
    v.push_back(4);
    v.push_back(4);
    k -= n * (n - 1) / 2 + 3 * n;
    while(k >= n){
        v.push_back(4);
        k -= n;
    }
    for(int i=3; k>=3; ++i){
        if(isPrime[i+2] && isPrime[i+4]){
            v.push_back(i);
            k -= 3;
        }
    }
    for(int i=3; k>=2; ++i){
        if(!isPrime[i+2] && isPrime[i+4]){
            v.push_back(i);
            k -= 2;
        }
    }
    for(int i=3; k>=1; ++i){
        if(isPrime[i+2] && !isPrime[i+4]){
            v.push_back(i);
            -- k;
        }
    }

    n = v.size();
    cout << n << endl;
    cout << v[0];
    for(int i=1; i<n; ++i)
        cout << ' ' << v[i];
    cout << endl;

    return 0;
}