#include<fstream>

using namespace std;

ifstream fin("fractii.in");
ofstream fout("fractii.out");

long n,v[1000001],nr;

int main()
{   long i,j;
    fin>>n;
    for(i=1;i<=n;i++)
        v[i]=i-1;
    for(i=1;i<=n;i++)
    {       for(j=2*i;j<=n;j+=i)
                v[j]=v[j]-v[i];
            nr+=v[i];
    }
    fout<<nr*2+1;
    fin.close();
    fout.close();
    return 0;
}