#include <iostream>
#include <vector>
#include <set>

using namespace std;

set<pair<int, int>> stars;

vector<pair<int, int>> stars2;


int main(void) {
	int n;
	cin >> n;
	for(int i = 0; i < n; i++) {
		int x, y;
		cin >> x >> y;
		stars.insert({x,y});
		stars2.push_back({x,y});
	}
	int count = 0;
	for (int i = 1; i < n; i++) {
		int dx = stars2[i].first - stars2[0].first;
		int dy = stars2[i].second - stars2[0].second;
		bool fail = false;
		for (int s = 0; s < n; s++) {
			pair<int, int> plus = {stars2[s].first + dx, stars2[s].second + dy};
			pair<int, int> minus = {stars2[s].first - dx, stars2[s].second - dy};
			if (stars.count(plus) == 0 && stars.count(minus) == 0) {
				fail = true;
				break;
			}
		}
		if (!fail)
			count += 1;
	}
	cout << 2 * count << endl;

}