**Time limit:**1.00 s**Memory limit:**512 MB

You are given a set of polygonal chains, and your task is to find out for each chain if it can be represented as a

*function*by rotating the figure. This means that no vertical line intersects the figure in two points.

**Input**

The first input line has an integer $t$: the number of polygonal chains. After this, each chain is described as follows:

The first line has an integer $n$: the number of points. After this, there are $n$ lines, each having two integers $x$ and $y$. No two consecutive points are the same, and no three consecutive points lie on the same line.

**Output**

For each polygonial chain, print

`YES`

if it can be represented as a function, and `NO`

otherwise.**Example**

Input:

`2`

4

0 0

2 1

3 -1

2 -2

4

0 0

2 1

3 -1

2 0

Output:

`YES`

NO

**Subtask 1 (45 points)**

- $1 \le t \le 100$

- $2 \le n \le 1000$

- $-100 \le x,y \le 100$

**Subtask 2 (55 points)**

- $1 \le t \le 100$

- $2 \le n \le 10^6$

- $\sum n \le 10^6$

- $-10^9 \le x,y \le 10^9$