Codeforces Round 509 (Div. 2)
F
Ray in the tube
Codeforces
2500
原题
← E→
翻译中…

You are given a tube which is reflective inside represented as two non-coinciding, but parallel to $Ox$ lines. Each line has some special integer points — positions of sensors on sides of the tube.

翻译中…

You are going to emit a laser ray in the tube. To do so, you have to choose two integer points $A$ and $B$ on the first and the second line respectively (coordinates can be negative): the point $A$ is responsible for the position of the laser, and the point $B$ — for the direction of the laser ray. The laser ray is a ray starting at $A$ and directed at $B$ which will reflect from the sides of the tube (it doesn't matter if there are any sensors at a reflection point or not). A sensor will only register the ray if the ray hits exactly at the position of the sensor.

翻译中…

image Examples of laser rays. Note that image contains two examples. The $3$ sensors (denoted by black bold points on the tube sides) will register the blue ray but only $2$ will register the red.

翻译中…

Calculate the maximum number of sensors which can register your ray if you choose points $A$ and $B$ on the first and the second lines respectively.

翻译中…

Input

翻译中…

The first line contains two integers $n$ and $y_1$ ($1 \le n \le 10^5$, $0 \le y_1 \le 10^9$) — number of sensors on the first line and its $y$ coordinate.

翻译中…

The second line contains $n$ integers $a_1, a_2, \ldots, a_n$ ($0 \le a_i \le 10^9$) — $x$ coordinates of the sensors on the first line in the ascending order.

翻译中…

The third line contains two integers $m$ and $y_2$ ($1 \le m \le 10^5$, $y_1 \lt y_2 \le 10^9$) — number of sensors on the second line and its $y$ coordinate.

翻译中…

The fourth line contains $m$ integers $b_1, b_2, \ldots, b_m$ ($0 \le b_i \le 10^9$) — $x$ coordinates of the sensors on the second line in the ascending order.

翻译中…

Output

翻译中…

Print the only integer — the maximum number of sensors which can register the ray.

翻译中…

Note

翻译中…

One of the solutions illustrated on the image by pair $A_2$ and $B_2$.

翻译中…

样例

Input #1
3 1
1 5 6
1 3
3
Output #1
3
InputCopy OutputCopy
题目信息
题号
1041F
时间限制
2 s
内存限制
256 MB
标签
数据结构
分治
动态规划
数学

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。