1661. Treasure Hunt

输入格式

The input will consist of several cases.

The first line of the input contains the number of cases, and it’s followed by a blank line.

The first line of each case will be an integer $n$ ($0\le n\le 30$) specifying number of interior walls, followed by $n$ lines containing integer endpoints of each wall $x_1{y}_1{x}_2{y}_2$. The 4 enclosing walls of the pyramid have fixed endpoints at $(0,0)$, $(0,100)$, $(100,100)$ and $(100,0)$ and are not included in the list of walls. The interior walls always span from one exterior wall to another exterior wall and are arranged such that no more than two walls intersect at any point. You may assume that no two given walls coincide. After the listing of the interior walls there will be one final line containing the floating point coordinates of the treasure in the treasure room (guaranteed not to lie on a wall).

Different cases are separated by a blank line.

输出格式

For each case, print a single line listing the minimum number of doors which need to be created, in the format shown below. Print a blank line between cases.

1
7
20 0 37 100
40 0 76 100
85 0 0 75
100 90 0 90
0 71 100 61
0 14 100 38
100 47 47 100
54.5 55.4

Number of doors = 2