#include<cstdio>#include<cstring>#include<algorithm>#include<cmath>using namespace std;const double eps=1e-10;int dcmp(double x){ if(fabs(x)<eps) return 0; return x<0?-1:1;}struct Point{ double x,y; Point(){} Point(double x,double y):x(x),y(y){}};typedef Point Vector;Vector operator+(Vector A,Vector B){ return Vector(A.x+B.x,A.y+B.y);}Vector operator-(Point A,Point B){ return Vector(A.x-B.x,A.y-B.y);}Vector operator*(Point A,double p){ return Vector(A.x*p, A.y*p);}Vector operator/(Point A,double p){ return Vector(A.x/p,A.y/p);}double Cross(Vector A,Vector B){ return A.x*B.y-A.y*B.x;}bool SegmentProperIntersection(Point a1,Point a2,Point b1,Point b2){ double c1=Cross(a2-a1,b1-a1),c2=Cross(a2-a1,b2-a1); double c3=Cross(b2-b1,a1-b1),c4=Cross(b2-b1,a2-b1); return dcmp(c1)*dcmp(c2)<0 && dcmp(c3)*dcmp(c4)<0;}const int maxn=2000+5;Point P[maxn],Q[maxn];int main(){ int n; while(scanf("%d",&n)==1) { for(int i=1;i<=n;++i) scanf("%lf%lf%lf%lf",&P[i].x,&P[i].y,&Q[i].x,&Q[i].y); bool ok=true; for(int i=1;i<=n;++i) for(int j=i+1;j<=n;++j) if(SegmentProperIntersection(P[i],Q[i],P[j],Q[j])) { ok=false; break; } printf("%sn",ok?"ok!":"burned!"); } return 0;}
