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; class Program { public void Solve() { int N = Reader.Int(); var A = new Point[N]; var B = new Point[N]; var candPos = new HashSet(); int ans = 0; for (int i = 0; i < N; i++) { var p = Reader.IntArray(4); A[i] = new Point(p[0], p[1]); B[i] = new Point(p[2], p[3]); candPos.Add(A[i]); candPos.Add(B[i]); } foreach (var S in candPos) foreach (var T in candPos) { long dx = T.X - S.X; long dy = T.Y - S.Y; var ss = new Point(S.X - dx * 10000, S.Y - dy * 10000); var tt = new Point(T.X + dx * 10000, T.Y + dy * 10000); int count = 0; for (int i = 0; i < N; i++) if (SegmentIntersect(ss, tt, A[i], B[i])) count++; ans = Math.Max(ans, count); } Console.WriteLine(ans); } bool SegmentIntersect(Point a1, Point a2, Point b1, Point b2) { long c1 = (a2 - a1).Det(b1 - a1); if (c1 == 0 && (a1 - b1).InnerProduct(a2 - b1) <= 0) return true; long c2 = (a2 - a1).Det(b2 - a1); if (c2 == 0 && (a1 - b2).InnerProduct(a2 - b2) <= 0) return true; long c3 = (b2 - b1).Det(a1 - b1); if (c3 == 0 && (b1 - a1).InnerProduct(b2 - a1) <= 0) return true; long c4 = (b2 - b1).Det(a2 - b1); if (c4 == 0 && (b1 - a2).InnerProduct(b2 - a2) <= 0) return true; return c1 * c2 < 0 && c3 * c4 < 0; } struct Point : IEquatable, IComparable { public long X, Y; public Point(long x, long y) { X = x; Y = y; } public static Point operator +(Point a, Point b) { return new Point(a.X + b.X, a.Y + b.Y); } public static Point operator -(Point a, Point b) { return new Point(a.X - b.X, a.Y - b.Y); } public long DistSquare(Point b) { return (X - b.X) * (X - b.X) + (Y - b.Y) * (Y - b.Y); } public double Dist(Point b) { return Math.Sqrt(DistSquare(b)); } public long InnerProduct(Point b) { return X * b.X + Y * b.Y; } public long Det(Point b) { return X * b.Y - Y * b.X; } public bool OnSegment(Point a, Point b) { return (a - this).Det(b - this) == 0 && (a - this).InnerProduct(b - this) <= 0; } public override int GetHashCode() { return (int)(X * 100000 + Y); } public bool Equals(Point b) { return X == b.X && Y == b.Y; } public int CompareTo(Point b) { return X != b.X ? Math.Sign(X - b.X) : Math.Sign(Y - b.Y); } public override string ToString() { return X + ", " + Y; } } } 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 => Line()).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; } }