#include <cstdio>
#include <algorithm>

using namespace std;


#define file_in "trapez.in"
#define file_out "trapez.out"

#define Nmax 1010

struct panta
{
	int x,y;
}
p[Nmax];

int n,t,nr;
int x[Nmax];
int y[Nmax];

int cmp(panta a, panta b)
{
	return (a.x<b.x);
}	

int main()
{
	int i,j;
	freopen(file_in,"r",stdin);
	freopen(file_out,"w",stdout);
	
	scanf("%d", &n);
	for (i=1;i<=n;++i)
		 scanf("%d %d", &x[i],&y[i]);
	
	nr=0;
	for (i=1;i<n;++i)
		 for (j=i+1;j<=n;++j)
		 {
			 nr++;
			 p[nr].x=y[j]-y[i];
			 p[nr].y=x[j]-x[i];
		 }
	
	sort(p+1,p+nr+1,cmp);

	t=0;
	for (i=1;i<nr;++i)
		 for (j=i+1;j<=nr;++j)
			  if (p[i].x*p[j].y==p[i].y*p[j].x)
				   t++;
	
	printf("%d", t);

	fclose(stdin);
	fclose(stdout);
	
	return 0;
}