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题号：NC239447
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
Special Judge, 64bit IO Format: %lld

题目描述

Ranran has a set $s_v$ of $n$ vectors and an integer $d$ . He is bored at Sunday so he decides to invent a new problem for you.

You need to give a set $s_p$ of points, size of which is $m$ . You will pick up every point $(a_i, b_i)$ in $s_p$ and every vector $(x_j, y_j)$ in $s_v$ . The pair $(a_i,b_i,x_j,y_j)$ is called good if and only if the line $(a_i + tx_j, b_i + ty_j), t\in \mathbb{R}$ visits exactly $d$ points in $s_p$ . $s_p$ is good if and only if every pair satisfies the condition. You need to find out a good set of points.

Ranran thinks about it at a few sleepless nights thinking of Yangyang and solves it. Now he gives this problem to you. Can you solve it?

输入描述:

The first contains two integers  and .

Each of the next  lines contains two integers . 

Attention, it is not guarenteed that all vectors are pairwise different.

输出描述:

Output an integer  in the first line.

Each of the next  lines, output two integers .

You should guarantee that ,  are 32-bit signed integers and points are pairwise different.

示例1

输入

复制

1 1
1 0

输出

复制

1
0 0

说明

The conditions can be satisfied using only one point.