#include <stdio.h>
#define N 2000012
char sol[1024],v[N]={0};
int main()
{
int n,nr=0,i,j;
freopen("ciur.in", "r",stdin);
freopen("ciur.out", "w",stdout);
scanf("%d", &n);
	for(i=2;i<=n;++i)
		if(v[j]==0)
		for(j=i+i;j<=n;j+=i)
            v[j]=1;
for(i=n;i>=2;--i)
 {if(v[i]==0) sol[nr++]=i; 
  if(nr>1000) break;}
printf("%d\n",nr);
 
 for(i=nr-1;i>=0;--i)
	  printf("%d ", sol[i]); 
		 printf("\n");
	 
return 0;
}