#include <fstream>
using namespace std;

#define IN "fractii.in"
#define OUT "fractii.out"

ifstream fin(IN);
ofstream fout(OUT);

void citire();
void rezolva();
int divizor(long, long);

long n,numar;

int main()
{
    citire();
    rezolva();
    fout<<(numar-1)*2+1<<'\n';
    return 0;
}

void citire()
{
fin>>n;
}

void rezolva()
{
    long i,j;
for(i=1;i<=n/2;i++)
for(j=1;j<=n;j++)
if( divizor(i,j) ==1) numar++;
}


int divizor(long a,long b)
{
 int rest;
    while(b!=0)
    {
    rest=a%b;
    a=b;
    b=rest;
    }

return a;
}