#include <algorithm>
#include <bitset>
using namespace std;
#define dim 2000001
bitset <dim> v;
long q[dim];
int main()
{
	long n, f=1;
	freopen ("numere2" , "r" , stdin);
	freopen ("numere2", "w", stdout);
	
	scanf("%d" , &n);
	
	
	q[0]=1;
	
	for(int i=2;i<n;++i)
	{
		++i;
		if(!v[i])
		{
			++f;
			q[f]=i;
			for(int j=i;j<=n/i;++j)
			{
				v[i*j]=1;
				++j;
			}
		}
	}
	int gasit=0;
	int j=1;
	while(gasit==0)
	{
	}
	
	
	
	
	
	//printf("%ld", f);
	
	return 0;
}