#include <stdio.h>
#include <vector>
#define NMax 2000000

long n, lg;
char ciur[NMax];
std::vector<long> prime;

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

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

	scanf( "%ld", &n );

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

	return 0;
}