#include <iostream>
#include <vector>
#define pb push_back

using namespace std;

bool pr[2000001];
vector<int> v;

void Ciur(){
    for(int i = 2 ; i <= 1000005 ; ++i)
        if(pr[i] == 0)
            for(int j = i + i ; j <= 1000005 ; j += i)
                pr[j] = 1;
}

int main()
{
    int n;
    cin>>n;
    v.pb(1);
    Ciur();
    for(int i = 2 ; i <= n ; ++i)
        if(!pr[i])
            v.pb(i);
    cout<<v.size()<<'\n';
    for(int i = 0 ; i < v.size() ; ++i)
        cout<<v[i]<<' ';
    return 0;
}