Jecka is making a choose-your-own-adventure game. In this genre of video games, there are multiple scenes each with a choice between two different options that lead to different scenes, called choice scenes. There are also ending scenes: scenes that do not have any options. To make her life easier, Jecka represents each scene with a unique integer ID from ~1~ to ~N+M~.

Since Jecka wants to make sure her playerbase is entertained by the game, she needs to fulfill their requirements of the game. Specifically, they will only enjoy a game that has exactly ~M~ endings and ~N~ non-ending scenes. So, she looks to you to help her design such a game!

Jecka is an organized person, so she wants the IDs of the scenes to satisfy the following rules:

• Scene ~1~ must be the starting scene; that is, there may not be any choice scenes that lead to it
• Scenes ~1~ to ~N~ must be choice scenes
• Scenes ~N+1~ to ~N+M~ must be ending scenes

Additionally, all scenes must be reachable from scene ~1~ (for completeness!) and no choice scene can have itself as an option (that's boring!).

Can you help her craft a game that follows these requirements?

Constraints

~1 \leq N \leq 2 \times 10^5~

~2 \leq M \leq 2 \times 10^5~

Input Specification

The first line will contain two integers, ~N~ and ~M~, the number of choice scenes and ending scenes required, respectively.

Output Specification

Output ~N~ lines, each line ~l_i~ containing two integers denoting the ID of the scenes that can be reached from scene ~i~. If it is not possible to make a game that fulfills the audience's requirements, output -1. If there are multiple possible arrangements, output any.

Sample Input 1

1 4

Sample Output 1

-1

Explanation for Sample 1

It is not possible to create a game that has ~4~ endings but only ~1~ non-ending scene.

Sample Input 2

2 2

Sample Output 2

2 3
3 4

Explanation for Sample 2

The graph looks like this:

Scenes ~3~ and ~4~ are endings while ~1~ and ~2~ are choice scenes.