#include <stdio.h>

FILE * iesire, *intrare;

int cmmdc(int a, int b){
  int rest;

  while(b){
   rest = a%b;
   a = b;
   b = rest;
  }

  return a;
}

int main(){

    int n;

    iesire = fopen("fractii.out", "w");
    intrare = fopen("fractii.in", "r");

    fscanf(intrare, "%d", &n);

    int nrTotal;

    nrTotal = 2*n-1;

    int i, j;

    for(i=2; i<n; i++)
     for(j=i+1; j<=n; j++){
       if(cmmdc(i, j)==1){
	   nrTotal+=2;

	   printf("%d/%d\n",i,j);
	 }
     }

   fprintf(iesire, "%d", nrTotal);
   fclose(iesire);
   fclose(intrare);

   return 0;
}