#include <iostream>
#include <vector>
#include <stack>
#include <algorithm>

#define NMax 100005

using namespace std;

vector <int> G[NMax];
vector < vector <int> > BC;
stack < pair <int, int> > Stack;
int N, Level[NMax], LowestL[NMax];

void Read ()
{
    freopen ("biconex.in", "r", stdin);
    int M;
    scanf ("%d %d", &N, &M);
    for (; M>0; --M)
    {
        int X, Y;
        scanf ("%d %d", &X, &Y);
        G[X].push_back (Y);
        G[Y].push_back (X);
    }
}

void Print ()
{
    freopen ("biconex.out", "w", stdout);
    printf ("%d\n", BC.size ());
    for (int i=0; i<BC.size (); ++i)
    {
        sort (BC[i].begin (), BC[i].end ());
        printf ("%d ", BC[i][0]);
        for (int j=1; j<BC[i].size (); ++j)
        {
            if (BC[i][j]!=BC[i][j-1])
            {
                printf ("%d ", BC[i][j]);
            }
        }
        printf ("\n");
    }
}

inline int Min (int a, int b)
{
    if (a<b)
    {
        return a;
    }
    return b;
}

void DetBC (int X, int Y)
{
    int x, y;
    vector <int> Component;
    do
    {
        x=Stack.top ().first;
        y=Stack.top ().second;
        Stack.pop ();
        Component.push_back (x);
        Component.push_back (y);
    }
    while (x!=X or y!=Y);
    BC.push_back (Component);
}

void DFS (int X, int Father, int L)
{
    Level[X]=LowestL[X]=L;
    for (unsigned i=0; i<G[X].size (); ++i)
    {
        int V=G[X][i];
        if (V==Father)
        {
            continue;
        }
        if (Level[V]==0)
        {
            Stack.push (make_pair (X, V));
            DFS (V, X, L+1);
            LowestL[X]=Min (LowestL[X], LowestL[V]);
            if (LowestL[V]>=Level[X])
            {
                DetBC (X, V);
            }
        }
        else
        {
            LowestL[X]=Min (LowestL[X], LowestL[V]);
        }
    }
}

int main()
{
    Read ();
    for (int i=1; i<=N; ++i)
    {
        if (Level[i]==0)
        {
            DFS (i, 0, 1);
        }
    }
    Print ();
    return 0;
}