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

#define NMax 100005
#define x first
#define y second

using namespace std;

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

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)
    {
        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)
{
    vector <int> Component;
    int CX, CY;
    do
    {
        CX=Stack.top ().x;
        CY=Stack.top ().y;
        Stack.pop ();
        Component.push_back (CX);
        Component.push_back (CY);
    }
    while (CX!=X or CY!=Y);
    sort (Component.begin (), Component.end ());
    BC.push_back (Component);
}

void DFS (int X, int F, int L)
{
    Level[X]=MinLevel[X]=L;
    for (vector <int> :: iterator V=G[X].begin (); V!=G[X].end (); ++V)
    {
        if (*V==F)
        {
            continue;
        }
        if (Level[*V]==0)
        {
            Stack.push (make_pair (X, *V));
            DFS (*V, X, L+1);
            MinLevel[X]=Min (MinLevel[X], MinLevel[*V]);
            if (MinLevel[*V]>=Level[X])
            {
                DetBC (X, *V);
            }
        }
        else
        {
            MinLevel[X]=Min (MinLevel[X], MinLevel[*V]);
        }
    }
}

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