#include<fstream> 
using namespace std;

long long a[1000001],n,s,i,j,fin; 

void read()
{
	ifstream in("fractii.in");
	in>>n;
	in.close();
}

int main()
{
	read();
	for(i=1;i<=n;i++)
		a[i]=i-1;  

	for(i=1;i<=n;i++)
	{  
            for(j=i*2;j<=n;j=j+i)  
            	a[j]-=a[i];  
            s+=a[i];  
        }  
	fin=(s*2)+1;

	ofstream out("fractii.out");  
        out<<fin;  
        out.close();  
}