#include <stdio.h>
#define NMax 2000005

int n, lg, prime[1024];
char ciur[NMax];


int main()
{
	long i, j, nr;

	freopen( "ciur.in", "rt", stdin );
	freopen( "ciur.out", "wt", stdout );

	scanf( "%d", &n );

	for (i=2; i<=n; i++)
		if ( !ciur[i] )
		{
			for (j=i+i; j<=n; j+=i)
				if ( j <= n && j % i == 0 )
					ciur[j] = 1;
			prime[lg++] = i;
		}
	
	printf( "%d\n", lg );
	for (i=0; i<lg; i++)
		printf( "%d ", prime[i] );
	printf( "\n" );

	return 0;
}