#include <iostream>
#include <fstream>

using namespace std;

#define Nmax 1000005

int ciur[Nmax];
long long sol = 0;
int N;

int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");

    f >> N;

    for ( int i = 2; i <= N; ++i )
            ciur[i] = i - 1;

    for ( int i = 2; i <= N; ++i )
    {
        for ( int j = i << 1; j <= N; j += i )
                ciur[j] -= ciur[i];

        sol += ciur[i];
    }

    g << 2*sol+1;

    return 0;
}