#include <bits/stdc++.h>
#define x first
#define y second

const int MV = 1505 ;

std::pair<float, float> v[MV] ;

float dist(std::pair<float, float> x, std::pair<float, float> y) {
  float maxx = std::max(x.x, y.x) ;
  float minx = x.x + y.x - maxx ;
  float maxy = std::max(x.y, y.y) ;
  float miny = x.y + y.y - maxy ;
  return sqrt((maxx - minx) * (maxx - minx) + (maxy - miny) * (maxy - miny)) ;
}

int main() {
  freopen("triang.in", "r", stdin) ;
  freopen("triang.out", "w", stdout) ;
  int n, ans(0), i, j, k ;
  scanf("%d", &n) ;
  for (i = 1 ; i <= n ; ++ i) {
    std::cin >> v[i].x >> v[i].y ;
  }
  for (i = 1 ; i <= n ; ++ i) {
    for (j = i + 1 ; j <= n ; ++ j) {
      for (k = j + 1 ; k <= n ; ++ k) {
        if (dist(v[i], v[j]) == dist(v[j], v[k]) && dist(v[j], v[k]) == dist(v[k], v[i]))
          ans ++ ;
      }
    }
  }
  printf("%d", ans) ;
  return 0 ; }