#include <iostream>
#include <cmath>
#include <fstream>
using namespace std;
int fct(int n)
     {
       int result = n;
       for(int i=2;i*i <= n;i++)
       {
         if (n % i == 0) result -= result / i;
         while (n % i == 0) n /= i;
       }
       if (n > 1) result -= result / n;
       return result;
     }
int main()
{
    unsigned long long nr=0;
    int n;
    ifstream fin("fractii.in");
    fin>>n;
    ofstream fout("fractii.out");
    for( int a=2;a<=n;nr+=fct(a++));
    nr<<=1;
    nr++;
    fout<<nr;
    cout<<nr;
}