#include using namespace std; #define all(c) (c).begin(),(c).end() #define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--) #define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++) #define rep(i,n) REP(i,0,n) #define iter(c) __typeof((c).begin()) #define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++) #define mem(a) memset(a,0,sizeof(a)) #define pd(a) printf("%.10f\n",a) #define pb(a) push_back(a) #define in(a) insert(a) #define pi M_PI #define R cin>> #define F first #define S second #define C class #define ll long long #define ln cout<<'\n' #define _(_1,_2,_3,N,...)N #define pr(...) _(__VA_ARGS__,pr3,pr2,pr1)(__VA_ARGS__) templatevoid pr1(T a){cout<void pr2(T a,T2 b){cout<void pr3(T a,T2 b,T3 c){cout<void PR(T a,int n){rep(i,n){if(i)cout<<' ';cout<=0&&x=0&&y P; double cross(const P& a, const P& b) {return imag(conj(a)*b);} bool intersectLS(const vector

&l, const vector

&s) { return cross(l[1]-l[0],s[0]-l[0])*cross(l[1]-l[0],s[1]-l[0])> n; vector

l[n]; rep(i,n) { double x1,x2,y1,y2; cin >> x1 >> y1 >> x2 >> y2; l[i].pb(P(x1,y1)); l[i].pb(P(x2,y2)); } int ans=0; rep(i,n) { REP(j,i,n) { rep(k1,2) { rep(k2,2) { vector

a; a.pb(l[i][k1]); a.pb(l[j][k2]); int cnt=0; rep(x,n) { if(intersectLS(a,l[x])) cnt++; } ans=max(ans,cnt); } } } } pr(ans); } int main() { ios::sync_with_stdio(0);cin.tie(0); Main();return 0; }