using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Tiil = System.Tuple<int, int, long>;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	
	public void Solve(){
		
		List<Tiil> L = new List<Tiil>();
		for(int i=0;i<N;i++){
			for(int j=i+1;j<N;j++){
				L.Add(new Tiil(i, j, (X[i] - X[j]) * (X[i] - X[j]) + (Y[i] - Y[j]) * (Y[i] - Y[j])));
			}
		}
		
		L.Sort((p, q) => p.Item3.CompareTo(q.Item3));
		
		int cnt = 0;
		bool[] disappear = new bool[N];
		foreach(var p in L){
			if(disappear[p.Item1] || disappear[p.Item2]) continue;
			if(p.Item1 != 0 && p.Item2 != 0){
				disappear[p.Item1] = true;
				disappear[p.Item2] = true;
				continue;
			}
			if(p.Item1 == 0 && p.Item2 != 0){
				disappear[p.Item2] = true;
				cnt++;
				continue;
			}
			if(p.Item1 != 0 && p.Item2 == 0){
				disappear[p.Item1] = true;
				cnt++;
				continue;
			}
		}
		
		Console.WriteLine(cnt);
		
		
	}
	int N;
	long[] X,Y;
	public Sol(){
		N = ri();
		X = new long[N];
		Y = new long[N];
		for(int i=0;i<N;i++){
			var d = ria();
			X[i] = d[0]; Y[i] = d[1];
		}
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(char sep=' '){return Console.ReadLine().Split(sep);}
	static int[] ria(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>int.Parse(e));}
	static long[] rla(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>long.Parse(e));}
	static double[] rda(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>double.Parse(e));}
}