#include<fstream>
#include<vector>
#define dmax 1004
#define er 0.00000001
using namespace std;
ifstream in("trapez.in");
ofstream out("trapez.out");

long long n,sol;
double u;

struct point
{	long long x;
	long long y;
}	p[dmax];

vector<double>m;
vector<double>::iterator it;

typedef int (*compfn)(const void *,const void *);

int sf(struct point *a,struct point *b)
{	if(a->x != b->x)
		return a->x - b->x;
	return a->y - b->y;
}	



double mx(double k)
{	if(k<0)return -1 * k;
	return k;
}

int main()
{	int i,j;
	in>>n;
	for(i=0;i<n;i++)
		in>>p[i].x>>p[i].y;
	in.close();	
	qsort( (void*)&p, n, sizeof(struct point), (compfn)sf );
	for(i=1;i<n;i++)
		for(j=0;j<i;j++)
		{	u=( (double)p[i].y - (double)p[j].y) / (double)(p[i].x - (double)p[j].x);
			for(it=m.begin();it<m.end();it++)
			{	if( max(u-*it,*it-u) <=	er)
					sol++;
			}
			m.push_back(u);
		}
	out<<sol;
	out.close();
	return 0;
}