#include <iostream>
#include<fstream>
#include<cmath>

using namespace std;

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

int p[1000001];

int main()
{
    long long n,s=0,i,j;
    f>>n;

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

    for(i = 2; i <= n; i++)
      for(j = i + i; j <= n; j += i)
          p[j] -= p[i];

      for(i = 1; i <= n; i++)
        s = s + p[i];
        g << 2*s + 1;

    f.close();
    g.close();
    return 0;
}