#include <fstream>
#define DIM 1000005
#define ll long long
using namespace std;

ifstream is("fractii.in");
ofstream os("fractii.out");

int n, v[DIM];
ll rez;

int main()
{
    int i, j;
    is >> n;

    v[1] = 1;
    for(i = 2; i <= n; ++i)
        v[i] = i - 1;

    for(i = 2; i <= n; ++i){
        rez += v[i];
        for(j = 2 * i; j <= n; j+=i)
            v[j] = v[j] - v[i];
    }

    os << 2 * rez + 1;

    is.close();
    os.close();
    return 0;
}