#include<stdio.h>
long long n,v[1000002],i,j;

int main()  
   {  
       FILE*f=fopen("fractii.in","r");  
       FILE*g=fopen("fractii.out","w");   
       fscanf(f,"%lld",&n);  
       for (i = 1; i <= n; ++i)
           v[i] = i-1;
       for (i = 2; i <= n; ++i)
           for (j = 2*i; j <= n; j = j+i)
               v[j] -= v[i];
       long long nr=0;
       for(i=1;i<=n;i++)
             nr=nr+v[i];
       fprintf(g,"%lld",2*nr+1);
       fclose(f);
       fclose(g);  
       return 0;
}