#include <cstdio>
#include <vector>
using namespace std;

int main()
{	
	freopen ("fractii.in","r", stdin);
	freopen ("fractii.out","w", stdout);

	int n,anz=0,r,a,b;
	vector <int> zahlen;
	scanf ("%d", &n);

	zahlen.resize (n+1);

	for (int i=1;i<=n;i++)
	{
		for (int j=1;j<=n;j++)
			zahlen[j]=1;
		for (int j=1;j<=n;j++)
		{
			if (zahlen[j]==1)
			{
				a=i;
				b=j;
				do
				{
					r=a%b;
					a=b;
					b=r;
				}
				while (r!=0);
				if (a==1)
					anz++;
				else
					for (int t=j+j;t<=n;t+=j)
						zahlen[t]=0;
			}
		}
	}
		
	printf ("%d \n", anz);
	
}