#include <fstream>

using namespace std;

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

int divizor(int a, int b)
{
    while (a != b)
    {
        if (a>b)
            a = a - b;
        else
            b = b - a;
    }
    return a;
}

int main()
{
    short int p=1, q=0, s=0;
    int n;
    in >> n;
    while (p<=n)
    {
        q++;
        if (divizor(p,q) == 1)
        {
            s++;
        }
        if (q == n)
        {
            p++;
            q = 0;
        }
    }
    out << s;
}