#include <cstdio>
#include <math.h>
#include <algorithm>
#include <functional>
#include <vector>
#define pdd pair<double,double>
#define M_PI  3.14159265358979323846
#define eps 1e-3
#define x first
#define y second

using namespace std;

const double s60 = sin(60 * M_PI / 180.0);    
const double c60 = cos(60 * M_PI / 180.0);
const double offset = 50000.0;
const int nmax = 1502;
const int mod = 666013;
int n;
pdd v[nmax];

inline pair<pdd,pdd> getPoints(pdd a,pdd b) {
	return make_pair( 
		make_pair(c60 * (a.x - b.x) - s60 * (a.y - b.y) + b.x,
				  s60 * (a.x - b.x) + c60 * (a.y - b.y) + b.y),
		make_pair(c60 * (a.x - b.x) + s60 * (a.y - b.y) + b.x,
				  -	s60 * (a.x - b.x) + c60 * (a.y - b.y) + b.y ));
}


inline int comp(const double &a,const double &b) {
	if(b - a < eps && b - a > - eps) return 0;
	if(b - a < -eps) return -1;
	return 1;
}

inline void readData() {
	scanf("%d",&n);
	for(int i = 0;i < n;i++) {
		scanf("%lf %lf",&v[i].x,&v[i].y);
	}
}

inline bool search(pdd p) {
	int pos = 0;
	for(int step = 1<<11;step > 0;step >>= 1) {
		if(pos + step < n && comp(p.x,v[pos].x) <= 0) {
			pos += step;
		}
	}

	for(int step = 1<<11;step > 0;step >>= 1) {
		if(pos + step < n && comp(p.y,v[pos].y) <= 0) {
			pos += step;
		}
	}
	return (comp(p.x,v[pos].x) == 0 && comp(p.y,v[pos].y) == 0);
}

inline int solve() {
	int ret = 0;
	sort(v,v + n);
	for(int i = 0;i < n;i++) {
		for(int j = i + 1;j < n;j++) {
			pair< pdd ,pdd > points = getPoints(v[i],v[j]);
			ret += search(points.x);
			ret += search(points.y);
		}
	}
	return ret;
}

int main()
{
    freopen("triang.in","r",stdin);
    freopen("triang.out","w",stdout);
	readData();
	printf("%d\n",solve());
    return 0;
}