#include<fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
int n,i,j,nr;
int cmmdc(int a, int b)
{if(a==b)return a;
if(a>b)return cmmdc(a-b,b);
  else return cmmdc(a,b-a);
}
int numarare(int n)
{for(i=2;i<=n/2;i++)
	for(j=1;j<=n;j++)
		if(cmmdc(i,j)==1)nr++;
nr+=nr;
if(n%2)for(i=1;i<=n/2;i++)if(cmmdc((n/2)+1,i)==1)nr++;
return nr+n;
}
int main()
{f>>n;
g<<numarare(n);
return 0;
}