#P1198C. Matching vs Independent Set

    ID: 4321 Type: RemoteJudge 1000ms 256MiB Tried: 0 Accepted: 0 Difficulty: 7 Uploaded By: Tags>constructive algorithmsgraphsgreedysortings*2000

Matching vs Independent Set

Description

You are given a graph with 3n3 \cdot n vertices and mm edges. You are to find a matching of nn edges, or an independent set of nn vertices.

A set of edges is called a matching if no two edges share an endpoint.

A set of vertices is called an independent set if no two vertices are connected with an edge.

The first line contains a single integer T1T \ge 1 — the number of graphs you need to process. The description of TT graphs follows.

The first line of description of a single graph contains two integers nn and mm, where 3n3 \cdot n is the number of vertices, and mm is the number of edges in the graph (1n1051 \leq n \leq 10^{5}, 0m51050 \leq m \leq 5 \cdot 10^{5}).

Each of the next mm lines contains two integers viv_i and uiu_i (1vi,ui3n1 \leq v_i, u_i \leq 3 \cdot n), meaning that there is an edge between vertices viv_i and uiu_i.

It is guaranteed that there are no self-loops and no multiple edges in the graph.

It is guaranteed that the sum of all nn over all graphs in a single test does not exceed 10510^{5}, and the sum of all mm over all graphs in a single test does not exceed 51055 \cdot 10^{5}.

Print your answer for each of the TT graphs. Output your answer for a single graph in the following format.

If you found a matching of size nn, on the first line print "Matching" (without quotes), and on the second line print nn integers — the indices of the edges in the matching. The edges are numbered from 11 to mm in the input order.

If you found an independent set of size nn, on the first line print "IndSet" (without quotes), and on the second line print nn integers — the indices of the vertices in the independent set.

If there is no matching and no independent set of the specified size, print "Impossible" (without quotes).

You can print edges and vertices in any order.

If there are several solutions, print any. In particular, if there are both a matching of size nn, and an independent set of size nn, then you should print exactly one of such matchings or exactly one of such independent sets.

Input

The first line contains a single integer T1T \ge 1 — the number of graphs you need to process. The description of TT graphs follows.

The first line of description of a single graph contains two integers nn and mm, where 3n3 \cdot n is the number of vertices, and mm is the number of edges in the graph (1n1051 \leq n \leq 10^{5}, 0m51050 \leq m \leq 5 \cdot 10^{5}).

Each of the next mm lines contains two integers viv_i and uiu_i (1vi,ui3n1 \leq v_i, u_i \leq 3 \cdot n), meaning that there is an edge between vertices viv_i and uiu_i.

It is guaranteed that there are no self-loops and no multiple edges in the graph.

It is guaranteed that the sum of all nn over all graphs in a single test does not exceed 10510^{5}, and the sum of all mm over all graphs in a single test does not exceed 51055 \cdot 10^{5}.

Output

Print your answer for each of the TT graphs. Output your answer for a single graph in the following format.

If you found a matching of size nn, on the first line print "Matching" (without quotes), and on the second line print nn integers — the indices of the edges in the matching. The edges are numbered from 11 to mm in the input order.

If you found an independent set of size nn, on the first line print "IndSet" (without quotes), and on the second line print nn integers — the indices of the vertices in the independent set.

If there is no matching and no independent set of the specified size, print "Impossible" (without quotes).

You can print edges and vertices in any order.

If there are several solutions, print any. In particular, if there are both a matching of size nn, and an independent set of size nn, then you should print exactly one of such matchings or exactly one of such independent sets.

Sample Input 1

4
1 2
1 3
1 2
1 2
1 3
1 2
2 5
1 2
3 1
1 4
5 1
1 6
2 15
1 2
1 3
1 4
1 5
1 6
2 3
2 4
2 5
2 6
3 4
3 5
3 6
4 5
4 6
5 6

Sample Output 1

Matching
2
IndSet
1
IndSet
2 4
Matching
1 15

Note

The first two graphs are same, and there are both a matching of size 1 and an independent set of size 1. Any of these matchings and independent sets is a correct answer.

The third graph does not have a matching of size 2, however, there is an independent set of size 2. Moreover, there is an independent set of size 5: 2 3 4 5 6. However such answer is not correct, because you are asked to find an independent set (or matching) of size exactly nn.

The fourth graph does not have an independent set of size 2, but there is a matching of size 2.