#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <iterator>

#define pb push_back

using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

const int CMAX = 100015;
int n , m , x , y;
int low[CMAX] , niv[CMAX];
int comp = 0;
vector < int > v[CMAX];
vector < int > compot[CMAX];
stack < int > st;
bool viz[CMAX];

void citire()
{
    fin >> n >> m;
    for(int i=1;i<=m;i++)
    {
        fin >> x >> y;
        v[x].pb(y);
        v[y].pb(x);
    }
}

void afis_stiva()
{
    stack < int > itr;
    itr = st;
    cout << itr.size() << '\n';
    while(itr.size())
    {
        cout << itr.top() << " ";
        itr.pop();
    }
    cout << '\n';
}

void dfs(int nod,int tata)
{
    viz[nod] = 1;
    low[nod] = niv[nod];
    st.push(nod);
    for(int i=0;i<v[nod].size();i++)
    {
        int w = v[nod][i];
        if(w==tata)continue;

        if(viz[w])
        {
            low[nod] = min(low[nod],niv[w]);
            continue;
        }

        niv[w] = niv[nod] + 1;

        dfs(w,nod);

        low[nod] = min(low[nod],low[w]);

        if(niv[nod]<=low[w])
        {
            //afis_stiva();
            comp++;
            int u;
            do
            {
                u = st.top();
                st.pop();
                compot[comp].pb(u);
            }while(st.size()&&w!=u);
            compot[comp].pb(nod);
        }
    }
}

int main()
{
    citire();
    dfs(1,0);
    fout << comp << '\n';
    for(int i=1;i<=comp;i++)
    {
        for(int j=0;j<compot[i].size();j++)
        {
            fout << compot[i][j] << " ";
        }
        fout << '\n';
    }
    return 0;
}