Given a undirected graph with $N$ vertices and $M$ edges. $i$-th edge is $(a_ i, b_ i)$. This graph may not be simple.
Please decompose this graph into two-edge-connected components.
$N$ $M$
$a_ 0$ $b_ 0$
$a_ 1$ $b_ 1$
:
$a_ {M - 1}$ $b_ {M - 1}$
Print the number of two-edge-connected components $K$ in the first line.
Following $K$ lines, print as follows. $l$ is the number of vertices of two-edge-connected components and $v_ i$ is a vertex index.
$l$ $v_ 0$ $v_ 1$ ... $v_ {l-1}$
If there is multiple solutions, print any of them.
4 5 0 2 0 1 3 0 2 1 2 3
1 4 0 2 1 3
13 21 4 5 8 7 12 3 3 10 1 5 10 2 0 0 11 4 2 12 9 1 9 0 7 8 7 6 9 1 8 2 12 10 11 0 8 6 3 2 5 9 4 11
3 6 0 9 1 5 4 11 4 2 10 3 12 3 6 7 8
2 2 0 1 1 0
1 2 0 1
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