#include <iostream>
#include <fstream>
#include <set>

using namespace std;

using i64 = long long;
constexpr size_t LIM = 1005;

set<pair<i64, i64>> points;
pair<i64, i64> points_array[LIM];
int N, i, j, ans;
double x, y;

static inline i64 read_i64(ifstream& fin) {
	i64 ans = 0, sign = 1;
	char ch;

	while (fin >> ch && ch != '.') {
		if (ch == '-') sign = -1;
		else ans = ans * 10 + ch - '0';
	}

	for (int k = 0; k < 4; k++) {
		fin >> ch;
		ans = ans * 10 + ch - '0';
	}

	return ans * sign;
}

static inline void read() {
	ifstream fin("patrate3.in");

	fin >> N;
	for (i = 0; i < N; i++) {
		x = read_i64(fin);
		y = read_i64(fin);
		points_array[i] = make_pair(x, y);
		points.insert(points_array[i]);
	}

	fin.close();
}

static inline void write() {
	ofstream fout("patrate3.out");
	fout << ans;
	fout.close();
}
static inline void solve() {
	for (i = 0; i < N; i++) {
		for (j =0; j < N; j++) {
			if (points_array[i] < points_array[j]) {
				const auto& p1 = points_array[i];
				const auto& p2 = points_array[j];

				pair<i64, i64> diff = { abs(p1.first - p2.first), abs(p1.second - p2.second) };
				const i64 x = diff.first, y = diff.second;
				diff.first = -y, diff.second = x;

				pair<i64, i64>  p3 = { p1.first + diff.first, p1.second + diff.second };
				pair<i64, i64>  p4 = { p2.first + diff.first, p2.second + diff.second };

				if (points.find(p3) != points.end() && points.find(p4) != points.end()) ans++;
			}
		}
	}
}

int main() {
	read();
	solve();
	write();
	return 0;
}