#include <iostream>
#include<fstream>
using namespace std;


int euclid(int a,int b)
{
    int c;
    while(b)
    {
        c=a%b;
        a=b;
        b=c;
    }
    return a;
}


int main()
{

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

  long int n;
   f>>n;

   int numitor=1,numarator=1,nr=0;

   while(numarator<=n)
   {
       if(euclid(numitor,numarator)==1)
           nr++;

       if(numitor==n)
       {
        numitor=1;
        numarator++;
       }
       else
        numitor++;
   }

   g<<nr;


    return 0;
}