#include <fstream>
using namespace std;

struct segm{short int a,b;};
segm v[1<<20];
short int a[1<<10],b[1<<10];

ifstream in("trapez.in");
ofstream out("trapez.out");

inline bool tg(segm a,segm b)
{
	return a.a*b.b==a.b*b.a;
}

int main()
{
	int n,i,j,k,t;
	long long nr=0;
	in>>n;
	for (i=1;i<=n;i++)
		in>>a[i]>>b[i];
	for (i=2,k=0;i<=n;i++)
		for (j=1;j<i;j++)
		{
			v[++k].a=a[i]-a[j];
			v[k].b=b[i]-b[j];
			for (t=1;t<k;t++)
				nr+=tg(v[k],v[t]);
		}
	out<<nr<<"\n";
	return 0;
}