include<stdio.h>  
char c[2000001];  
int v[1001];  
int main()  
{  
    freopen("ciur.in","r",stdin);  
    freopen("ciur.out","w",stdout);  
    c[0]=c[1]=1;  
    int n,i,j,k=0;  
    scanf("%d",&n);  
    for(i=4; i<=n; i+=2)  
        c[i]=1;  
    for(i=3; i*i<=n; i+=2)  
    {  
        if(!c[i])  
        {  
            for(j=i+i+i; j<=n; j+=i+i)  
                c[j]=1;  
        }  
    }  
    for(i=n; i>1; i--)  
    {  
        if(!c[i])  
        {  
            k++;  
            if(k<1001)  
                v[k]=i;  
        }  
    }  
    printf("%d\n",k);  
    if(k>=1000)  
    {  
        for(i=1000; i>0; i--)  
            printf("%d ",v[i]);  
    }  
    else  
    {  
       for(i=k; i>0; i--)  
            printf("%d ",v[i]);  
    }  
    printf("\n");  
    return 0;  
}