#include<iostream>
#include<fstream>
#include<math.h>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
//fractii ireductibile

float ireductibil(int x,int y)
{
        int p=1;//presupunem ca e ireductibila
        
        if(x%2==0 && y%2==0)p=0;
         else if(x==y)p=0;
          else if((x%2==0 && y%2==1) &&((x%y==0)||(y%x==0)))p=0;
        
        
        return p; 
     }


int main()
{   int k=0; float n;
    f>>n;
    
   float i,j;
    i=1;j=1;
    while(i<=n)
       {if(ireductibil(i,j))k++;
         j++;
         if(j==n)i++;
          
        }
       g<<k;

   return 0;
}