#include typedef long long ll; typedef unsigned long long ull; #define FOR(i,a,b) for(int (i)=(a);i<(b);i++) #define REP(i,n) FOR(i,0,n) #define RANGE(vec) (vec).begin(),(vec).end() using namespace std; template struct Pt { T x, y; Pt(T x0, T y0) : x(x0), y(y0) {} Pt() :x(0),y(0) {} const Pt operator+(const Pt &other) const { return Pt(x+other.x, y+other.y); } const Pt operator-(const Pt &other) const { return Pt(x-other.x, y-other.y); } Pt &operator+=(const Pt &other) { x += other.x; y += other.y; return *this; } Pt &operator-=(const Pt &other) { x -= other.x; y -= other.y; return *this; } Pt operator*(double r) const { return Pt(x*r, y*r); } bool operator<(const Pt &other) const { return (x < other.x)? true : ((x==other.x)? (y < other.y) : false); } bool operator<=(const Pt &other) const { return (*this == other)? true : (*this < other); } bool operator>(const Pt &other) const { return (other < *this); } bool operator>=(const Pt &other) const { return (other <= *this); } bool operator==(const Pt &other) const { return (x==other.x && y==other.y); } bool operator!=(const Pt &other) const { return !(operator==(other)); } double norm(void) const { return hypot(x, y); } // class method static double cross(const Pt &a, const Pt &b) { return ((double)a.y*b.x - (double)a.x*b.y); } static double dot(const Pt &a, const Pt &b) { return (double)a.x*b.x+(double)a.y*b.y; } static int ccw(const Pt &a, const Pt &b) { double area = cross(a, b); if (area > 0) return 1; // counter clockwise if (area < 0) return -1; // clockwise return 0; // on line } }; template Pt operator*(double r, const Pt &p) { return p*r; } template void make_unique(std::vector &vec) { std::sort(vec.begin(), vec.end()); vec.erase(unique(vec.begin(), vec.end()), vec.end()); } class GoThrough { public: void solve(void) { int N; cin>>N; typedef Pt Point; vector> line; vector points; REP(i,N) { Point p,q; cin>>p.x>>p.y>>q.x>>q.y; line.emplace_back(p,q); points.push_back(p); points.push_back(q); } make_unique(points); int n = points.size(); // 端点を通る直線を総当たりすればよい // O(N^3) // int ret = 1; // 少なくとも1つはそんざいする REP(i,n) FOR(j,i+1,n) { Point p,q; p = points[i]; q = points[j]; int cnt = 0; REP(k,N) { Point u,v; tie(u,v) = line[k]; if ( Point::ccw(p-q, u-q) * Point::ccw(p-q, v-q) <= 0 ) ++cnt; } ret = max(ret,cnt); } cout<solve(); delete obj; return 0; } #endif