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

$1\le N\le 2\times {10}^5$

$2\le M\le 2\times {10}^5$

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.