#include <iostream>
#include <fstream>
using namespace std;

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


int main()
{int i,j,n;
 long nr=0;
 int v[30];
 f>>n;
 for(i = 1; i <= n;i++)
        v[i] = i-1;
        for(i=1;i<=n-i;i++)
          for(j=i+1;j<=n;j+=i)
          v[j] -= v[i];
          for( i = 1; i <= n; i++)
        nr += v[i];
        g<<nr*2+1;


    return 0;
}