#include <cstdio>
#include <cmath>
#include <algorithm>
using namespace std;

#define MAXN 1505
#define EPS 0.0001

double X[MAXN], Y[MAXN];

struct cmp {
  bool operator()(const int &a, const int &b){
    if(abs(X[a]-X[b]) < EPS)
      return Y[a]<Y[b];
    else
      return X[a]<X[b];
  }
};

inline double L(double x1, double y1, double x2, double y2){
  return (x2-x1)*(x2-x1)+(y2-y1)*(y2-y1);
}

int main(){

  freopen("triang.in", "r", stdin);
  freopen("triang.out", "w", stdout);

  int N, i, j, k, I[MAXN], cnt;
  static double D[MAXN][MAXN];

  scanf("%d", &N);
  for(i=1; i<=N; i++){
    scanf("%lf%lf", X+i, Y+i);
    I[i]=i;
  }

  sort(I+1, I+N+1, cmp());

  for(i=1; i<=N; i++)
    for(j=1; j<=N; j++)
      D[i][j]=L(X[I[i]], Y[I[i]], X[I[j]], Y[I[j]]);

  cnt=0;
  for(i=1; i<=N; i++)
    for(j=i+1; j<=N; j++)
      for(k=j+1; k<=N; k++)
	if(abs(D[i][j]-D[j][k])<EPS && abs(D[j][k]-D[k][i])<EPS)
	  cnt++;

  printf("%d\n", cnt);

  return 0;

}