#include<iostream>
#include<fstream>
using namespace std;
int main()
{
    ifstream fin("fractii.in");
    ofstream fout("fractii.out");
    unsigned n;
    fin>>n;
    unsigned s=0;
    int phi[1000000];
    for (int i=1;i<=n;i++)
        phi[i]=i-1;
    for (int i=2;i<=n;i++)
    {
        for (int j=2*i;j<=n;j=j+i)
            phi[j]=phi[j]-phi[i];
        s=s+phi[i];
    }
    fout<<s*2+1;
}