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#15209. 屏障

统计

在二维平面上有一个矩形房间。房间里有一些障碍物,每个障碍物都可以表示为一条没有厚度的线段。

请计算从房间中心可以看到的房间墙壁的总长度。保证房间的中心为 $(0, 0)$。

输入格式

第一行包含一个整数 $n$ ($1 \le n \le 1000$),表示障碍物的数量。

接下来 $n$ 行,每行包含四个整数 $x_1, y_1, x_2, y_2$ ($|x_1|, |y_1|, |x_2|, |y_2| \le 10000$),表示一个障碍物线段的起点和终点。

再接下来一行,包含四个整数 $l, r, u, d$ ($1 \le l, r, u, d \le 10000$),分别表示矩形房间的左、右、上、下边界与 $(0, 0)$ 的距离。

输出格式

输出一个实数,表示从 $(0, 0)$ 可以看到的房间墙壁的长度。

样例

输入样例 1

1
1 0 0 1
2 2 2 2

输出样例 1

12.00000000

说明

障碍物不会离 $(0, 0)$ 或墙壁太近。

当你的答案与标准答案的相对误差或绝对误差不超过 $10^{-4}$ 时,将被视为正确。

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