#include <fstream>
#include <iostream>
#include <stdio.h>
using namespace std ;
int n;
void afisare( char A[]);
char prime[200];
int main(void)
{ 
    int i ,j ,k=0;
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
    scanf("%d",&n);
	for(i=2;i<=n;i++)
		prime[i]=1;
	for(i=2;i<n;i++)
	{if(prime[i])
	{  k++;
	   for(j=i+i;j<=n;j=j+i)
		   prime[j]=0;
	}}
	cout<<k;
	afisare(prime);
	printf("%d\n",k);
	return 0;
}
void afisare( char A[])
{ int i=0;
for(i=0;i<n;i++)
	cout<<A[i]<<" ";
}