#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int cmmdc(int a,int b)
{
  while(a*b!=0)
  {
    if(a>b)
     a=a%b;
    else
     b=b%a;
  }
  return a+b;
}
int numara_fractii(int n)
{
    int i=1,nr=0;
    int j;
    while(i<n)
    {
     for(j=i+1;j<=n;j++)
     if(cmmdc(i,j)==1)
      nr++;
      i++;
    }
    return nr*2;
}
int n;
int main()
{
    fin>>n;
    fout<<numara_fractii(n);
    return 0;
}