Cowardly Rooks

Description:

Input:

The first line contains a single integer $$$t$$$ ($$$1 \le t \le 2000$$$) — the number of testcases.

The first line of each testcase contains two integers $$$n$$$ and $$$m$$$ ($$$1 \le n, m \le 8$$$) — the size of the chessboard and the number of the rooks.

The $$$i$$$-th of the next $$$m$$$ lines contains two integers $$$x_i$$$ and $$$y_i$$$ ($$$1 \le x_i, y_i \le n$$$) — the position of the $$$i$$$-th rook: $$$x_i$$$ is the row and $$$y_i$$$ is the column.

No two rooks occupy the same cell. No two rooks attack each other.

Output:

For each testcase, print "YES" if it's possible to move exactly one rook into a different cell so that no two rooks still attack each other. Otherwise, print "NO".

Sample Input:

2
2 2
1 2
2 1
3 1
2 2

Sample Output:

NO
YES

Note:

In the first testcase, the rooks are in the opposite corners of a $$$2 \times 2$$$ board. Each of them has a move into a neighbouring corner, but moving there means getting attacked by another rook.

In the second testcase, there's a single rook in a middle of a $$$3 \times 3$$$ board. It has $$$4$$$ valid moves, and every move is fine because there's no other rook to attack it.