#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vl;
typedef vector<vector<int>> vvi;
typedef vector<vector<long long>> vvl;
typedef long double ld;
typedef pair<int, int> P;

ostream& operator<<(ostream& os, const modint& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const static_modint<m>& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const dynamic_modint<m>& a) {os << a.val(); return os;}
template<typename T> istream& operator>>(istream& is, vector<T>& v){int n = v.size(); assert(n > 0); rep(i, n) is >> v[i]; return is;}
template<typename U, typename T> ostream& operator<<(ostream& os, const pair<U, T>& p){os << p.first << ' ' << p.second; return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : " "); return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : ""); return os;}
template<typename T> ostream& operator<<(ostream& os, const set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename S, auto op, auto e> ostream& operator<<(ostream& os, const atcoder::segtree<S, op, e>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}
template<typename S, auto op, auto e, typename F, auto mapping, auto composition, auto id> ostream& operator<<(ostream& os, const atcoder::lazy_segtree<S, op, e, F, mapping, composition, id>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}

template<typename T> void chmin(T& a, T b){a = min(a, b);}
template<typename T> void chmax(T& a, T b){a = max(a, b);}

int main(){
	int n;
	cin >> n;
	vector<long long> x(n), y(n);
	rep(i, n) cin >> x[i] >> y[i];
	set<pair<int, int>> se;
	rep(i, n){
		se.insert(make_pair(x[i], y[i]));
	}
	auto dist = [&](int i, int j){
		return (x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]);
	};
	int ans = 0;
	rep(i, n){
		map<long long, vector<int>> myMap;
		rep(j, n){
			if(j == i) continue;
			myMap[dist(i, j)].push_back(j);
		}
		for(auto& [tmp, v] : myMap){
			int m = v.size();
			rep(dummy1, m){
				for(int dummy2 = dummy1 + 1; dummy2 < m; dummy2++){
					int j = v[dummy1];
					int k = v[dummy2];
					int x_final = x[k] + (x[j] - x[i]);
					int y_final = y[k] + (y[j] - y[i]);
					if(x_final == x[i] && y_final == y[i]) continue;
					if(se.find(make_pair(x_final, y_final)) != se.end()){
//						cout << i << j << k << "\n";
						ans++;
					}
				}
			}
		}
	}
	cout << ans / 4 << "\n";
	return 0;
}