#include<stdio.h>
int n,i,j;
long long nr;
int cmmdc(int a,int b)
{if(b==0) return a;
 return cmmdc(b,a%b);}
int main()
{freopen("fractii.in","r",stdin);
 freopen("fractii.out","w",stdout);
 scanf("%d",&n);
 nr=2*n-1;
 for(i=2;i<=n;i++)
  if(i%2)
  {for(j=i+1;j<=n;j++)
	if(j%i)if(cmmdc(i,j)==1)nr=nr+2;}
  else
  {for(j=i+1;j<=n;j=j+2)
    if(j%i) if(cmmdc(i,j)==1) nr=nr+2; }
 printf("%lld",nr);
 fclose(stdout);
 return 0;}