#include <iostream>
#include<fstream>
#include<cmath>
using namespace std;
int p[1000001];
int main()
{
    long long n,s=0,i,j;
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    f>>n;
    for(i=1;i<=n;i++)
      p[i]=i-1;
    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;
}