/** Biconnected components, implementation time 15 minutes*/
#include <cstdio>
#include <algorithm>
#include <vector>
#include <stack>
#include <bitset>

#define Nmax 100005

using namespace std;
typedef pair<int,int> edge;

int N,M,nrb;
vector<int> G[Nmax],Bix[Nmax];
stack<edge> S;
bitset<Nmax> used,articulation;

int level[Nmax],upperMost[Nmax];


void Read()
{
    int a,b;
    scanf("%d%d",&N,&M);
    for(int i = 1; i <= M; ++i)
    {
        scanf("%d%d",&a,&b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
}

void output(int k)
{
    ++nrb;
    ///printf("Found biconnected component:\n");
    edge e;
    while(1)
    {
        e = S.top();
        S.pop();
        Bix[nrb].push_back(e.second);
        ///printf("%d %d\n",e.first,e.second);
        if(e.first == k)
            break;
    }
    Bix[nrb].push_back(k);
}

void DFS(int k,int dad)
{
    used[k] = true;
    level[k] = level[dad] + 1;
    upperMost[k] = level[k];
    for(auto it : G[k])
        if(!used[it])
        {
            S.push({k,it});
            DFS(it,k);
            upperMost[k] = min(upperMost[k],upperMost[it]);
            if(upperMost[it] >= level[k]) /// we can't reach any higher than k from it subtree
            {
                articulation[k] = true;
                output(k);
            }
        }
        else
            if(it != dad && level[it] < upperMost[k]) /// back edge which reaches higher than the current root.
                upperMost[k] = level[it];
}

void Output()
{
    printf("%d\n",nrb);
    for(int i = 1; i <= nrb; ++i)
    {
        for(auto it : Bix[i])
            printf("%d ",it);
        printf("\n");
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);

    Read();
    for(int i = 1; i <= N; ++i)
        if(!used[i])
            DFS(i,0);
    Output();
    return 0;
}