#include <stdio.h>   
#include <stdlib.h>       
  
int main()        
{        
FILE *in,*out;      
int i,j,n,v[1000001];   
long long nr=0;   
in=fopen("fractii.in","r");        
out=fopen("fractii.out","w");        
fscanf(in,"%d",&n);    
//v=(int*)malloc(n*sizeof(int));   
for(i=1;i<=n;++i)       
     v[i]=i-1;       
         
for(i=2;i<=n;++i)       
    {   
    for(j=2*i;j<=n;j+=i)       
          v[j]-=v[i];       
      nr+=v[i];   
    }       
fprintf(out,"%lld",2*nr+1);   
             
fclose(in);   
fclose(out);        
return 0;   
}