using System; using System.Collections; using System.Collections.Generic; using System.Collections.Specialized; using System.Text; using System.Text.RegularExpressions; using System.Linq; using System.IO; class Program { static void Main() { new Magatro().Solve(); } } class Magatro { private int N; private int[] X, Y; bool[,] B = new bool[40050, 40050]; private int[] Lx, Ly; private void Scan() { N = int.Parse(Console.ReadLine()); X = new int[N]; Y = new int[N]; for (int i = 0; i < N; i++) { var line = Console.ReadLine().Split(' '); X[i] = int.Parse(line[0]) + 20020; Y[i] = int.Parse(line[1]) + 20020; } } private void CalcL() { var resultX = new List(); var resultY = new List(); for (int x = -20; x <= 20; x++) { for (int y = -20; y <= 20; y++) { if (Math.Sqrt(x * x + y * y) < 20) { resultX.Add(x); resultY.Add(y); } } } Lx = resultX.ToArray(); Ly = resultY.ToArray(); } private bool C(int n) { if (B[X[n], Y[n]]) return false; for (int i = 0; i < Lx.Length; i++) { B[X[n] + Lx[i], Y[n] + Ly[i]] = true; } return true; } public void Solve() { Scan(); CalcL(); int ans = 0; for (int i = 0; i < N; i++) { if (C(i)) { ans++; } } Console.WriteLine(ans); } }