#include <bits/stdc++.h>
#define per pair<double,double>
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define eps 10e-5
#define MOD 7919
using namespace std;
const int NMAX = 1000 + 5;
int n,sol=0;
double x,y;
per a[NMAX];
vector < pair < double , pair < int, int > > > Hash[MOD];
inline double getdist(int i,int j)
{
    double x1 = a[i].f,y1=a[i].s,x2=a[j].f,y2=a[j].s;
    return (double(sqrt(1.0*(x2-x1)*(x2-x1)+1.0*(y2-y1)*(y2-y1))));
}

inline void add_hash(double dist,int i,int j)
{
    int mask = int(dist)%MOD;

    Hash[mask].pb(mp(dist,mp(i,j)));

    return ;
}

inline bool compara(double d1, double d2)
{
    if (abs(d1-d2)<eps) return true;
    return false;
}
inline bool check(double dist,int i,int j)
{
    int mask = int(dist)%MOD;
    for (auto &it : Hash[mask])
        if (compara(it.f,dist)==true&&i!=it.s.f&&j!=it.s.s&&i!=it.s.s&&j!=it.s.f)
        {
            double d1 = getdist(i,it.s.f);
            double d2 = getdist(j,it.s.s);
            double dd1 = getdist(i,it.s.s);
            double dd2 = getdist(i,it.s.f);
            if (compara(d1,d2)&&compara(d1,dist))return true;
            if (compara(dd1,dd2)&&compara(dd1,dist))return true;
        }
    return false;
}
int main()

{
    freopen("patrate3.in","r",stdin);
    freopen("patrate3.out","w",stdout);
    scanf("%d\n", &n);
    for (int i = 1; i<=n; ++i)
    {
        scanf("%lf %lf",&x, &y);
        x+=10000;
        y+=10000;
        a[i].f = x;
        a[i].s = y;
    }
    for (int i = 1; i<=n; ++i)
        for (int j = i + 1; j<=n; ++j)
        {
            double dist=getdist(i,j);
            add_hash(dist,i,j);
        }
    for (int i = 1; i<=n; ++i)
        for (int j = i + 1; j<=n; ++j)
        {
            double dist = getdist(i , j);
            sol += check(dist,i,j);
        }
    printf("%d\n",sol/2);
    return 0;
}