#include <iostream>
#include <fstream>

using namespace std;

ifstream f("fractii.in");
ofstream g("fractii.out");

int cmmdc(int a,int b)
{
   while(a!=b)
    if(a>b)
      a=a-b;
    else
      b=b-a;
   return a;
}

int main()
{
    int n,i,j,s=-1;
    cin>>n;
    for(i=1;i<=n;i++)
       for(j=i;j<=n;j++)
          if(cmmdc(i,j)==1)
            s=s+2;
     cout<<s;
    return 0;
}