#include <fstream> 
int MaxN=1000005; 
ifstream f("fractii.in"); 
ofstream g("fractii.out"); 
int k[MaxN],n; 
unsigned long long rez; 
int main() 
{f>>n; 
 f.close(); 
  rez=0; 
 for(int i=1;i<=n;++i) 
    k[i]=i-1;     
 for(i=1;i<=n;++i) 
    for(int j=i*2;j<=n;j+=i)
        k[j]=k[j]-k[i];       
    
 for(i=1;i<=n;++i)         
     rez=rez+k[i]; 
    
rez=rez*2+1; 
g<<rez; 
g.close(); 
return 0;}