#include<stdio.h>
long n,nr,nrf;
int cmmdc(long a,long b)
{
	long r,x;
	x=a;
	while(b)
	{
		r=a%b;
		a=b;
		b=r;
	}
	if(a==x||a==1)
		return 0;
	else
		return a;
}
int main()
{
	long i,j;
	FILE *f=fopen("fractii.in","r"),*g=fopen("fractii.out","w");
	fscanf(f,"%ld",&n);
	for(i=4;i<=n;i++)
	{printf("\n");
		for(j=2;j<=n/2;j++)
			if(cmmdc(i,j))
			{	nr++; printf("%ld/%ld ",i,j);}
	}
	nrf=n*n-nr*2-n+1;
	fprintf(g,"%ld",nrf);
	fclose(g);
	fclose(f);
	return 0;
}