// vision.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include <vector>
#include <map>

using namespace std;

int main()
{
	int N;
	cin >> N;

	vector<pair<int, int>> C(N);
	for (int i = 0; i < N; i++)
	{
		int x, y;
		cin >> x >> y;
		C[i] = pair<int, int>(x, y);
	}

	map<pair<int, int>, int> Cou;
	vector<vector<pair<int, int>>> D(N);
	for (int i = 0; i < N; i++)
	{
		D[i] = vector<pair<int, int>>(N);
		for (int j = 0; j < N; j++)
		{
			
			D[i][j] = pair<int, int>(C[j].first - C[i].first, C[j].second - C[i].second);

			if (i == 0)
				Cou[D[i][j]] = 1;
			else
			{
				pair<int, int> rev = pair<int, int>(-D[i][j].first, -D[i][j].second);
				if (Cou.find(D[i][j]) != Cou.end() && Cou[D[i][j]] == i)
				{
					Cou[D[i][j]]++;
				}
				else if (Cou.find(rev) != Cou.end() && Cou[rev] == i)
				{
					Cou[rev]++;
				}
			}
		}
	}

	int count = 0;
	for (pair<pair<int, int>, int> p : Cou)
	{
		if (p.second == N && (p.first.first != 0 || p.first.second != 0))
			count++;
	}

	cout << 2*count << "\n";

	return 0;
}

// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu

// Tips for Getting Started: 
//   1. Use the Solution Explorer window to add/manage files
//   2. Use the Team Explorer window to connect to source control
//   3. Use the Output window to see build output and other messages
//   4. Use the Error List window to view errors
//   5. Go to Project > Add New Item to create new code files, or Project > Add Existing Item to add existing code files to the project
//   6. In the future, to open this project again, go to File > Open > Project and select the .sln file