#include <fstream>
using namespace std;
int main()
{
	ifstream IN("fractii.in");
	ofstream OUT("fractii.out");
	int n;IN>>n;
	int output=n;
	int num=2,denum=1;
	int* matrix=new int[n-1];
	for(num=2;num<=n;num++)
	{
		output++;
		for(int i=2;i<=n;i++)
		{
			if(i%num==0 || num%i==0) matrix[i]=0;
			else matrix[i]=1;
			if(matrix[i]) output++;
		}
	}
	OUT<<output<<"\n";
}