#include <stdio.h>

FILE *f,*g;

long long n,i,j,a[100];

int cmmdc(long long x, long long y)
{
 long long r;
 r=x%y;
 while (r!=0)
	{
	 x=y;
	 y=r;
	 r=x%y;
	}
 return y;
}

int main()
{

 f=fopen("fractii.in","r");
 g=fopen("fractii.out","w");

 fscanf(f,"%lld", &n);
 fclose(f);
 a[1]=1;
 a[2]=3;
 if (n==1)
	fprintf(g,"%lld",a[1]);
  else
 if (n==2)
	fprintf(g,"%lld",a[2]);
  else
   {
    for (i=3;i<=n;i++)
    {
     a[i]=a[i-1];
     for (j=1;j<i;j++)
	 if (cmmdc(j,i)==1)
		a[i]+=2;
    }
    fprintf(g,"%lld", a[n]);
   }
 fclose(g);

 return 0;
}