#include<stdio.h>


#define M 10000
long v[M];

int main()
{long n,i,j;
 int k;

FILE *f=fopen("ciur.in","r");
FILE *g=fopen("ciur.out","w");

fscanf (f,"%ld",&n);

k=0;

for(i=2;i<=n;i++)
 v[i]=1;

for(i=2;i<=n;i++)
 if(v[i]) {for(j=2*i;j<=n;j=j+i)
	      v[j]=0;}

for(i=2;i<=n;i++)
 if(v[i]) k++;

fprintf(g,"%d\n",k);


for(i=2;i<=n;i++)
 if(v[i]) fprintf(g,"%ld ",i);

fclose(f);
fclose(g);
return 0;
}