#include <iostream>
#include <fstream>
using std::cout;
using std::cin;
using std::endl;

int N;

int main()
{
    //Read
    {
        std::ifstream input("fractii.in");
        input >> N;
    }

    //Rezolvare
    int contor = N + (N-1);
    for( int i = 2; i <= N; i++ )
    {
        for( int j = 2; j <= N; j++ )
        {
            bool adv = true;
            if( j > i )
            {
                for( int c = 2; c < i; c++ )
                {
                    if( j % c == 0 && i % c == 0)
                        adv = false;
                }
            }
            else
            {
                for( int c = 2; c < j; c++ )
                {
                    if( j % c == 0 && i % c == 0)
                        adv = false;
                }
            }

            if( adv )
            {
                if(i % j != 0 && j % i != 0)
                {
                    cout << i << "/" << j << endl;
                    contor++;
                }
            }
        }
    }

    //Ouput
    std::ofstream output("fractii.out");
    output << contor;
    return 0;
}