class Fence
  {
    public Point p1;
    public Point p2;
 
    Fence(Point a, Point b)
      { p1 = a; p2 = b; }

    public static boolean cross(Fence f, Point a, Point b)
      {
	return( (CCW(f.p1,f.p2,a)*CCW(f.p1,f.p2,b)<=0) &&
	        (CCW(a,b,f.p1)*CCW(a,b,f.p2)<=0));
      }

    static int CCW(Point p0, Point p1, Point p2)
      {
        double dx1, dx2, dy1, dy2;

        dx1 = p1.x - p0.x; dy1 = p1.y - p0.y;
        dx2 = p2.x - p0.x; dy2 = p2.y - p0.y;
        if (dx1*dy2 > dy1*dx2) return 1;
        if (dx1*dy2 < dy1*dx2) return -1;
        if ((dx1*dx2 < 0) || (dy1*dy2 < 0)) return -1;
        if ((dx1*dx1+dy1*dy1) < (dx2*dx2+dy2*dy2)) return 1;
        return 0;
      }
  }