#include<fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
long long n,v[10000001],contor=1;

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