#include <fstream>

using namespace std;

const int DIM = 1000010;
int phi[DIM];
int n;

int main()
{
    //calculez functia phi
    for (int i = 1;i < DIM;++i)
        phi[i] = i - 1;
    for (int i = 2;i < DIM;++i)
        for (int j = 2 * i;j < DIM;j += i)
            phi[j] -= phi[i];
    ifstream fin("fractii.in");
    ofstream fout("fractii.out");
    fin >> n;
    int s = 0;
    for (int i = 1;i <= n;++i)
        s += phi[i];
    //pentru o fractie am si inversu ei cu exceptia 1/1
    fout << 2 * s + 1 << "\n";
    fin.close();
    fout.close();
    return 0;
}