#include <fstream>

using namespace std;

int prim(int a)
{
	int i,j=1;
	for(i=2; i<=a; i++)
	{
		if(a%i==0) j=0;
	}
	return j;
}

int main()
{
	int n, p, q, nr=0;
	ifstream in("fractii.in");
		in>>n;
	in.close();
	nr+=n;
	for(p=2; p<=n; p++)
	{
		if(prim(p)) 
		{
			for(q=p; q<=n; q++)
			{
				if(q%p==0) nr-=2;
			}
			nr+=n-1;
		}
		else nr+=n-1;
	}
	ofstream out("fractii.out");
		out<<nr;
	out.close();
	return 0;
}