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

#define Nmax 100005

using namespace std;
vector<int> G[Nmax],bix[Nmax];
bitset<Nmax> used;
stack<int> S;
int low[Nmax],nivel[Nmax],nrb;
int N,M;

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

void Get(int k)
{
    while(S.top() != k){
        bix[nrb].push_back(S.top());
        S.pop();
    }
    bix[nrb].push_back(k);
}

void Biconex(int k,int dad)
{
    used[k] = 1;
    nivel[k] = nivel[dad] + 1;
    low[k] = nivel[k];
    for(vector<int>::iterator it = G[k].begin();it != G[k].end(); ++it)
        if(!used[*it])
        {
            S.push(*it);
            Biconex(*it,k);
            low[k] = min(low[k],low[*it]);
            if(nivel[k] <= low[*it]){
                ++nrb;
                Get(k);
            }
        }
        else
            if(*it != dad && nivel[*it] < low[k])
                low[k] = nivel[*it];
}

void Solve()
{
    for(int i = 1; i <= N; ++i)
        if(!used[i])
        {
            S.push(i);
            Biconex(i,0);
            S.pop();
        }
}

void Print()
{
    printf("%d\n",nrb);
    for(int i = 1; i <= nrb; ++i)
    {
        for(vector<int>::iterator it = bix[i].begin(); it != bix[i].end(); ++it)
            printf("%d ",*it);
        printf("\n");
    }
}

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

    Read();
    Solve();
    Print();

    return 0;
}