#include<stdio.h>
#define Nmax 20000001

FILE *fin=freopen("ciur.in","r",stdin),
     *fout=freopen("ciur.out","w",stdout);
     
int n;
long sol[1001];
char viz[Nmax];
     

void solve()
{
  int cont=0;
  for(int i=2;i<=n;i++)
    if(!viz[i])
    {
     for(int j=i;i*j<=n;j++)
       viz[i]=1;
      cont++;
    }
  printf("%d\n",cont);
  int cnt=0;
  for(int i=n;i>1;)
  if(!viz[i])
  {
    sol[++cnt]=i--;
    if(cnt==1000) break;
  }
  for(int i=cnt;i;i--)
    printf("%d ",sol[i]);
}
     
int main()
{
  scanf("%d",&n);
  solve();
  return 0;
}