#include<stdio.h>
char v[2000001];
int main()
{
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
	int i,j,n,q=0;
	scanf("%d",&n);
	for(i=2;i*i<=n;i++)
		if(v[j]==0)
			for(j=2*i;j<=n;j=j+i)
				{v[j]=1;
				q++;}
	printf("%d\n",n-q-1);
	q=0;
	for(i=2;i<=n;i++)	
			if(v[i]==0)
			{q++;
			if(q<=1000)		
				printf("%d ",i);
		}
		return 0;
}