#include <bits/stdc++.h>
using namespace std;

bool zs(int a){
	for(int j=2;j<=a/2;j++){
		if(a%j==0)	return false;			
	}
	return true;
}

int main(){
	int L,a=0,s=0;
	cin>>L;
	for(int i=2;i<=L/2;i++){
		if(zs(i)&&s+i<=L){
			s+=i;
			a++;
			cout<<i<<endl<<endl;
		}
	}
	cout<<a<<endl<<endl;
	return 0;
}