[USACO 2008 Feb S]Game of Lines
题号:NC24957
时间限制:C/C++/Rust/Pascal 1秒,其他语言2秒
空间限制:C/C++/Rust/Pascal 32 M,其他语言64 M
64bit IO Format: %lld

题目描述

Farmer John has challenged Bessie to the following game: FJ has a board with dots marked at N (2 ≤ N ≤ 200) distinct lattice points. Dot i has the integer coordinates Xi and Yi (-1,000 ≤ Xi ≤ 1,000; -1,000 ≤ Yi ≤ 1,000).
Bessie can score a point in the game by picking two of the dots and drawing a straight line between them; however, she is not allowed to draw a line if she has already drawn another line that is parallel to that line. Bessie would like to know her chances of winning, so she has asked you to help find the maximum score she can obtain.

输入描述:

* Line 1: A single integer: N
* Lines 2..N+1: Line i+1 describes lattice point i with two space-separated integers: Xi and Yi.

输出描述:

* Line 1: A single integer representing the maximal number of lines Bessie can draw, no two of which are parallel.
示例1

输入

复制
4
-1 1
-2 0
0 0
1 1

输出

复制
4

说明

Bessie can draw lines of the following four slopes: -1, 0, 1/3, and 1.