ACM94国际大学生编程竞赛东中心区试题-Descr iption



n the game of Jack Straws, a number of plastic or wooden "straws" are dumped on the table and players try to remove them one-by-one without disturbing the other straws. Here, we are only concerned with if various pairs of straws are connected by a path of touching straws. You will be given a list of the endpoints for some straws (as if they were dumped on a large piece of graph paper) and then will be asked if various pairs of straws are connected. Note that touching is connecting, but also two straws can be connected indirectly via other connected straws.



Input



A problem consists of multiple lines of input. The first line will be an integer n (1 < n < 13) giving the number of straws on the table. Each of the next n lines contain 4 positive integers, x1 , y1 , x2 and y2 , giving the coordinates, (x1　 y1 )　(x2　 y2 ) of the endpoints of a single straw. All coordinates will be less than 100. (Note that the straws will be of varying lengths.) The first stra