#include<cstdio>
int N;
void fractii()
{int i,P,Q;
	i=N;
	for(P=2;P<=N;P++)
		for(Q=1;Q<=N;Q++)
		{
			if((Q==1)||((P%Q!=0)&&(Q%P!=0)))
				i++;
		}
		printf("%d",i);
}
int main()
{
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	scanf("%d",&N);
	fractii();
	return 0;
}