#include <cstdio>
#include <algorithm>
#include <cmath>
#include <iostream>
using namespace std;
#define DIM 1505
#define eps 1e-8

double mabs(double x)
{
	return x<0?-x:x;
}

struct point
{
	double x, y;
	point(){x=y=0;}
	point (double X, double Y){ x=X, y=Y;}
	friend bool operator < (point P1, point P2)
	{
		if(P1.x+eps>P2.x)
			return 0;
		if (P1.x +eps < P2.x)
			return 1;
		else
			if (mabs(P1.x - P2.x)<=eps)
				if (P1.y +eps< P2.y)
					return 1;
		return 0;
		
	}
	
} P[DIM];




int n, sol;

void read()
{
	FILE *f = fopen("triang.in", "r");
	fscanf(f, "%d", &n);
	for (int i = 1; i <= n; ++i)
		fscanf(f, "%lf%lf", &P[i].x, &P[i].y);
	fclose(f);
}

double dist(point A, point B)
{
	return sqrt((A.x - B.x) * (A.x - B.x) - (A.y - B.y) * (A.y - B.y));
}

void solve()
{
	const double T = 3.1415 / 3;
	for (int i = 1; i <= n; ++i)
		for (int j = 1; j <= n; ++j)
			if (i != j)
			{
				point p1, p2;
				p1.x = cos(T) * (P[i].x - P[j].x) - sin(T) * (P[i].y - P[i].y);
				p1.y = sin(T) * (P[i].x - P[j].x) - cos(T) * (P[i].y - P[i].y);
				
			//	printf ("p1 %lf %lf\n", p1.x, p1.y);
				
				p2.x = cos(T) * (P[j].x - P[i].x) - sin(T) * (P[j].y - P[i].y);
				p2.y = sin(T) * (P[i].x - P[j].x) - cos(T) * (P[i].y - P[j].y);
				
			//	printf ("p2 %lf %lf\n", p2.x, p2.y);
				
				sol += binary_search(P+1, P+n+1, p1);
				sol += binary_search(P+1, P+n+1, p2);
				
			}
}

int main()
{
	read();
	sort(P+1, P+n+1);
//	cout<<binary_search(P+1,P+n+1,point(2,3.4644));
	solve();
	
	FILE *f = fopen("triang.out", "w");
	fprintf(f, "%d\n", sol/3);
	fclose(f);
	return 0;
}