#include<stdio.h>
int main(){
	freopen("ciur.in", "r", stdin);   
    freopen("ciur.out", "w", stdout);
	int n;
	scanf("%d" ,&n);
	int i,j,k, prime[20000];
	k=1;
	int v[700][700]={0};
	for(i=3; i<=n; i=i+2)
		if (v[i/700][i%700]==0){
			k++;
			prime[k]=i;
			for (j=2*i; j<=n; j=j+i)
				v[j/700][j%700]=1;
		}
	printf("%d\n", k);
	prime[1]=2;
	for (i=1; i<=k; i++)
		printf("%d ", prime[i]);
	
	
	
	return 0;
}