#include <iostream>
#include <fstream>

using namespace std;

int main (void)
{
  ifstream in;
  in.open("fractii.in");

  int n;
  in >> n;

  in.close();

  int *euclid = new int [n];

  for (int i = 0 ; i < n ; ++i)
    euclid[i] = i;

  for (int i = 1 ; i < n ; ++i)
    for (int j = 2 * i + 1 ; j < n ; j += i + 1)
      euclid[j] -= euclid[i];

  int sum = 0;
  for (int i = 0 ; i < n ; ++i)
    sum += euclid[i];  

  ofstream out;
  out.open("fractii.out");

  out << 2 * sum + 1;
  out.close();

  return 0;
}