#include <stdio.h>

char a[2000005];
int n,nr=0,z[1005];

int main(){
           int i,j;
           freopen("ciur.in","r",stdin);
           freopen("ciur.out","w",stdout);
           scanf("%ld",&n);
           for(i=2;i<=n;i++)
               a[i]=1;
           for(i=2;i<=n;i++)
               if(a[i]==1){
                   z[++nr]=i;
                   for(j=i+i;j<=n;j+=i)
                       a[j]=0;
               }
           printf("%d\n",nr);
           if(nr<=1000){
               for(i=2;i<=n;i++)
                   if(a[i]==1)
                       printf("%ld ",i);
           }
           else
               for(i=nr-1000+1;i<=nr;i++)
                   printf("%ld ",z[i]);
           fclose(stdout);
           return 0;
}