#include<stdio.h>  

#define M 200001
int v[M];
int w[2000];

int main()
{long n,i,j,k=0;

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

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

k=0;

for(i=2;i*i<=n;i++)
 if(v[i]==0) for(j=i+i;j<=n;j+=i)
	      v[j]=1;

for(i=2;i<=n;i++)
 if(v[i]==0){ k++;w[k]=i;if(k>=1000)break;}

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


for(i=1;i<=k;i++)
 fprintf(g,"%d ",w[i]);

fclose(f);
fprintf(g,"\n");

fclose(g);
return 0;
}