#include <iostream>
#include <fstream>

using namespace std;

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

int cmmdc(int a1, int a2)
{
    while (a1!=a2)
    {
        if (a1>a2)
            a1-=a2;
        else
            a2-=a1;
    }
    return a1;
}

int main()
{
    int N, nr=0;
    int P=1, Q=1;
    in >> N;
    while (P<=N)
    {
        if (cmmdc(P, Q) == 1)
        {
            nr++;
        }
        Q++;
        if (Q>N)
        {
            Q=1;
            P++;
        }
    }
    out << nr;
}