#include<fstream.h>
inline int verif(int i, int j)
{
 if (i%j==0 || j%i==0) return 0;
 return 1;
}

int main()
{
 int n=0, fr=0;
 ifstream fin("fractii.in");
 fin>>n;
 fin.close();
 fr = (n*2)-1;
 for (int i=2;i<=n;i++)
 {
  for (int j=2;j<=n;j++)
   if (verif(i,j)) { cout<<i<<"/"<<j<<"   "; fr++; } 
 }
 ofstream fout("fractii.out");
 fout<<fr;
 fout.close();
 return 0;
}