using System; using System.IO; using System.Linq; using System.Text; using System.Collections.Generic; using System.Diagnostics; //using System.Numerics; using Enu = System.Linq.Enumerable; public class Program { public void Solve() { int N = Reader.Int(); var segments = new Segment[N]; var candPos = new HashSet(); int ans = 0; for (int i = 0; i < N; i++) { var p = Reader.IntArray(4); segments[i] = new Segment(new Point(p[0], p[1]), new Point(p[2], p[3])); candPos.Add(segments[i].A); candPos.Add(segments[i].B); } foreach (var S in candPos) foreach (var T in candPos) if (S != T) { var line = new Line(S, T); int count = 0; foreach (var seg in segments) if (Intersect(line, seg)) count++; ans = Math.Max(ans, count); } Console.WriteLine(ans); } public bool Intersect(Line line, Segment seg) { return (line.B - line.A).Det(seg.A - line.A) * (line.B - line.A).Det(seg.B - line.A) <= 0; } public class Line { public Point A, B; public Point this[int i] { get { if (i == 0) return A; if (i == 1) return B; throw new ArgumentException(); } } public Line(Point a, Point b) { A = a; B = b; } public override string ToString() { return A + " - " + B; } } public class Segment { public Point A, B; public Point this[int i] { get { if (i == 0) return A; if (i == 1) return B; throw new ArgumentException(); } } public Segment(Point a, Point b) { A = a; B = b; } public override string ToString() { return A + " - " + B; } } public struct Point : IEquatable, IComparable { public static readonly double Eps = 1e-10; public double X, Y; public Point(double x, double y) { X = x; Y = y; } public static Point operator +(Point a, Point b) { return new Point(Add(a.X, b.X), Add(a.Y, b.Y)); } public static Point operator -(Point a, Point b) { return new Point(Add(a.X, -b.X), Add(a.Y, -b.Y)); } public static Point operator *(double d, Point p) { return new Point(p.X * d, p.Y * d); } public static Point operator *(Point p, double d) { return d * p; } public double Dot(Point b) { return Add(X * b.X, Y * b.Y); } public double Det(Point b) { return Add(X * b.Y, -Y * b.X); } public bool Equals(Point b) { return X == b.X && Y == b.Y; } public override bool Equals(object obj) { return Equals((Point)obj); } public static bool operator ==(Point a, Point b) { return a.Equals(b); } public static bool operator !=(Point a, Point b) { return !a.Equals(b); } public int CompareTo(Point b) { return X != b.X ? Math.Sign(X - b.X) : Math.Sign(Y - b.Y); } public override int GetHashCode() { return (int)(X * 100000 + Y); } public override string ToString() { return X + ", " + Y; } private static double Add(double a, double b) { if (Math.Abs(a + b) < Eps * (Math.Abs(a) + Math.Abs(b))) return 0; return a + b; } } } class Entry { static void Main() { new Program().Solve(); } } class Reader { private static TextReader reader = Console.In; private static readonly char[] separator = { ' ' }; private static readonly StringSplitOptions op = StringSplitOptions.RemoveEmptyEntries; private static string[] A = new string[0]; private static int i; private static void Init() { A = new string[0]; } public static void Set(TextReader r) { reader = r; Init(); } public static void Set(string file) { reader = new StreamReader(file); Init(); } public static bool HasNext() { return CheckNext(); } public static string String() { return Next(); } public static int Int() { return int.Parse(Next()); } public static long Long() { return long.Parse(Next()); } public static double Double() { return double.Parse(Next()); } public static int[] IntLine() { return Array.ConvertAll(Split(Line()), int.Parse); } public static int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); } public static int[][] IntTable(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); } public static string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Next()).ToArray(); } public static string Line() { return reader.ReadLine().Trim(); } private static string[] Split(string s) { return s.Split(separator, op); } private static string Next() { CheckNext(); return A[i++]; } private static bool CheckNext() { if (i < A.Length) return true; string line = reader.ReadLine(); if (line == null) return false; if (line == "") return CheckNext(); A = Split(line); i = 0; return true; } }