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

int main(){
	int n;
	cin >> n;
	
	pair<int, int> x[n];
	map<pair<int, int>, int> mp;
	for(int i = 0; i<n; i++){
		cin >> x[i].first >> x[i].second;
		
	}
	sort(x, x + n);
	for(int i = 0; i<n; i++){
		mp[x[i]] = i;
	}
	
	int last[n];
	fill(last, last + n, -1);
	set<pair<int, int> > s;
	int cur = 0;
	int ans = 0;
	int cnt;
	
	for(int j = 1; j<n; j++){
		cnt = 2;
		if(s.count({x[j].first - x[0].first, x[j].second - x[0].second})) continue;
		int dx = x[j].first - x[0].first;
		int dy = x[j].second - x[0].second;
		
		last[0] = cur;
		last[j] = cur;
		
		for(int k = 1; k<n; k++){
			if(mp.count(make_pair(x[k].first + dx, x[k].second + dy))){
				last[mp[{x[k].first + dx, x[k].second + dy}]] = cur;
				last[k] = cur;
			}
		}
		
		cnt = 0;
		for(int k = 1; k<n; k++){
			if(last[k] == cur) cnt++;
		}
		
		if(cnt == n - 1) ans+=2;
		cur++;
	}
	
	cout << ans << endl;
}