#include #include #include #include #include #include #include #include #include #include #include using namespace std; struct Point{ int x; int y; Point(){} Point(int x_, int y_):x(x_),y(y_){} }; int side(const Point& a1, const Point& a2, const Point& p){ return (a2.x - a1.x) * (p.y - a1.y) - (a2.y - a1.y) * (p.x - a1.x); } bool cross(const Point& a1, const Point& a2, const Point& b1, const Point& b2){ int s1 = side(a1, a2, b1) * side(a1, a2, b2); int s2 = side(b1, b2, a1) * side(b1, b2, a2); if(s1 <= 0 || s2 <= 0){ return true; } return false; } int main(){ int N; cin >> N; vector > line(N); vector cand(N*2); for(int i = 0; i < N; i++){ cin >> line[i].first.x; cin >> line[i].first.y; cin >> line[i].second.x; cin >> line[i].second.y; cand[i*2] = line[i].first; cand[i*2+1] = line[i].second; } int ans = 0; for(int i = 0; i < cand.size(); i++){ for(int j = 0; j < cand.size(); j++){ if(cand[i].x == cand[j].x && cand[i].y == cand[j].y) continue; int cnt = 0; for(int i = 0; i < N; i++){ if(cross(line[i].first, line[i].second, cand[i], cand[j])) cnt++; } ans = max(ans, cnt); } } cout << ans << endl; return 0; }