#include<stdio.h>
#include<iostream.h>
#include<math.h>
long n,v[1250];
void prim(long k)
{
	int p=0;
	for(long i=0;i<sqrt(k);i++)
	{
		if(!k%i)
		{	
			v[p++]=i;
			while(!k%i)
				k/=i;
		}
	}
	v[p++]=k;
	v[p]=0;
	
}
			
long t(long k)
{
	prim(k);
	int p=0;
	long rez;
	double totient;
	while(v[p])
		totient=totient*(1-1./(double)v[p++]);
	rez=(int)totient +1;	
}
int main()
{
	long i;
	long long fract;
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	cin>>n;
	for(i=2;i<n;i++)
		fract+=t(i);
	fract*=2;fract++;
	cout<<fract;
	return 0;
}