#include <bits/stdc++.h>

using namespace std;

vector<pair<double,double> > xy;

int n;
double x,y;
int visited[2001];
vector<vector<pair<int, double> > > graph;
int a[2005][2];
vector<vector<int>> g;

vector<pair<int,int> > Van;

double length(double x1, double y1, double x2, double y2)
{
	return sqrt( (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2) );
}

int f(int idx, int from, bool put){
	if(a[idx][put]==-1){
		int sum_ = 0;
		if(put){
			for(auto i_:g[idx]){
				if(i_ != from)
					sum_ += f(i_,idx,0);
			}
		} else {
			for(auto i_:g[idx]){
				if(i_!=from){
				sum_ += max(f(i_,idx, 0), f(i_,idx,1));
				}
			}
		}
		a[idx][put] = sum_ + put;
	}
	return a[idx][put];
}

int main() {
	ios::sync_with_stdio(0);
	while(cin>>n)
	{
		memset(visited,0,sizeof(visited));
		for(int i=0;i<n;i++){
			cin>>x>>y;
			xy.push_back(make_pair(x,y));
			vector<pair<int,double> > vector1;
			graph.push_back(vector1);
		}

		for(int i=0;i<n;i++)
		{
			for(int j=0;j<n;j++)
			{
				if(i!=j)
				{
					double len = length(xy[i].first,xy[i].second,xy[j].first,xy[j].second);
					graph[i].push_back(make_pair(j,len));
				}
			}
		}

		priority_queue<pair<double,pair<int,int> > ,vector<pair<double,pair<int,int> > >, greater<pair<double, pair<int,int> > > > q;
		q.push(make_pair(0.0, make_pair(0,0)));

		while(!q.empty())
		{
			pair<double, pair<int,int> > top = q.top();
			q.pop();
			if(!visited[top.second.first])
			{
				if(top.second.second != 0 || top.second.first != 0)
				{
					Van.push_back(make_pair(top.second.second,top.second.first));
				}

				for(int i=0;i< graph[top.second.first].size() ; i++)
				{
					if(!visited[graph[top.second.first][i].first])
					{
						q.push(make_pair(graph[top.second.first][i].second, make_pair(graph[top.second.first][i].first, top.second.first)));
					}
				}
				visited[top.second.first] = 1;
			}

		}


		xy.clear();
		graph.clear();
		// sem pis kod

		g.clear();
		g.resize(n+1);

		for(auto& i_:Van){
			g[i_.first].push_back(i_.second);
			g[i_.second].push_back(i_.first);
		}

		memset(a,-1,sizeof(a));

		cout << max(f(0,-1,0),f(0,-1,1)) << endl;

		Van.clear();
	}

	return 0;
}