#include using namespace std; const double EPS = 1e-6; const double INF = 1e12; typedef complex P; namespace std { bool operator < (const P& a, const P& b) { return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b); } } double cross(const P& a, const P& b) { return imag(conj(a)*b); } double dot(const P& a, const P& b) { return real(conj(a)*b); } struct L : public vector

{ L(const P &a, const P &b) { push_back(a); push_back(b); } }; int ccw(P a, P b, P c) { b -= a; c -= a; if (cross(b, c) > 0) return +1; // counter clockwise if (cross(b, c) < 0) return -1; // clockwise if (dot(b, c) < 0) return +2; // c--a--b on line if (norm(b) < norm(c)) return -2; // a--b--c on line return 0; } typedef vector

G; struct C { P p; double r; C(const P &p, double r) : p(p), r(r) { } }; bool intersectLL(const L &l, const L &m) { return abs(cross(l[1]-l[0], m[1]-m[0])) > EPS || // non-parallel abs(cross(l[1]-l[0], m[0]-l[0])) < EPS; // same line } bool intersectLS(const L &l, const L &s) { return cross(l[1]-l[0], s[0]-l[0])* // s[0] is left of l cross(l[1]-l[0], s[1]-l[0]) < EPS; // s[1] is right of l } bool intersectSS(const L &s, const L &t) { return ccw(s[0],s[1],t[0])*ccw(s[0],s[1],t[1]) <= 0 && ccw(t[0],t[1],s[0])*ccw(t[0],t[1],s[1]) <= 0; } int main(void){ int n; cin >> n; vector lines; vector

pts; double a,b,c,d; for(int i=0;i> a >> b >> c >> d; P p1(a,b),p2(c,d); L l(p1,p2); pts.push_back(p1); pts.push_back(p2); lines.push_back(l); } int ret = 0; for(int i=0;i