#include <bits/stdc++.h>
using namespace std;

typedef long long LL;
typedef long double LD;
typedef pair < int, int > PII;
typedef pair < LL, LL > PLL;

#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()

struct point {
	int x, y;
};

point operator+(point a, point b) {
	return point{a.x + b.x, a.y + b.y};
}

point operator-(point a, point b) {
	return point{a.x + b.x, a.y + b.y};
}

const int N = 1005;

int n;
vector < point > vec;
vector < point > tmp;

bool operator <(const point &p1, const point &p2)
{
	if(p1.x == p2.x)
		return p1.y < p2.y;
	return p1.x < p2.x;
}

bool operator ==(const point &p1, const point &p2)
{
	return p1.x == p2.x && p1.y == p2.y;
}

bool check(point v)
{
	tmp.clear();
	for(int i = 0; i < n; i++)
	{
		point t = vec[i] + v;
		auto it = lower_bound(all(vec), t);
		if(it != vec.end() && *it == t)
		{
			tmp.push_back(t);
			tmp.push_back(vec[i]);
		}
	}
	sort(all(tmp));
	tmp.erase(unique(all(tmp)), tmp.end());
	return sz(tmp) == n;
}

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);

	cin >> n;
	vec.resize(n);
	for(int i = 0; i < n; i++)
	{
		cin >> vec[i].x >> vec[i].y;
	}
	sort(all(vec));

	int ans = 0;	
	for(int i = 0; i < n; i++)
	{
		if(check(vec[i] - vec[0]))
			ans++;
	}
	cout << (ans - 1) * 2 << "\n";

	return 0;
}