#include <fstream>
#include <vector>
#define nmax 20000
const double h1 = 1.58457398;
const double h2 = 0.317837245;
const double s  = 0.866025404;


using namespace std;

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

vector< pair < double,double> >Hash[nmax];

struct p{double x,y;}V[nmax];

inline int intreg(double x){return x;}
inline double modul(double x){if(x<0)return -x;return x;}

inline int cauta(double x,double y)
{
    int i,x1=intreg(modul(x*h1+y*h2));
    double x2,y2;
    for(i=0;i<Hash[x1].size();i++)
    {
        x2 = Hash[x1][i].first;
        y2 = Hash[x1][i].second;
        if(modul(x-x2)<0.0001&&modul(y-y2)<0.0001)
            return 1;
    }
    return 0;
}

int main()
{
    int N,i,j,nr_tr;
    double x,y,x1,y1,x2,y2;
    in>>N;
    for(i=0;i<N;i++)
    {
        in>>x>>y;
        V[i].x=x,V[i].y=y;
        //inserez in hash in functie de x si y
        //partea intreaga din x*h1 + y*h2
        Hash[ intreg(modul(x*h1+y*h2)) ].push_back(make_pair(x,y));
    }
    for(i=0;i<N;i++)
        for(j=i+1;j<N;j++)
        {
            //calculez al treilea punct :
            //c = -a*e - b*e^2
            x1=V[i].x,y1=V[i].y,x2=V[j].x,y2=V[j].y;
            x = (-x1-y1+x2+y2) /2;
            y = (-x1 - y1 +x2+y2)*s;
            //caut x y
            if(cauta(x,y))
                nr_tr++;
            x = (-x2-y2+x1+y1) /2;
            y = (-x2 - y2 +x1+y1)*s;
            if(cauta(x,y))
                nr_tr++;
        }
    out<<nr_tr;
    return 0;
}