#include<fstream>
using namespace std;
long n,i,v[1000001],j;
long long nr;
int main()
{

  fstream in("fractii.in");
 ofstream out("fractii.out");
    in>>n;
for(i=1;i<=n;i++)
v[i]=i-1;
for(i=1;i<=n;i++)
{for(j=2*i;j<=n;j=j+i)
v[j]=v[j]-v[i];
nr=nr+v[i];}
out<<2*nr+1;
return 0;
}