#include <iostream>
#include <bits/stdc++.h>

using namespace std;

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

const int N = 100005;
vector<int>a[N],componenta_biconexa;
vector<vector<int>>componente_biconexe;
stack<int> s;
int viz[N];
int n,m,nivel[N];

void citire()
{
    int x,y,i;
    in >> n >> m;
    for(i = 1 ; i <= m ; i++)
    {
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}

void dfs(int nod,int tata)
{
    int vecin;
    viz[nod] = 1;
    nivel[nod] = nivel[tata] + 1;
    viz[nod] = nivel[nod];
    s.push(nod);
    for(size_t i = 0 ; i < a[nod].size(); i++)
    {
        vecin = a[nod][i];
        if(vecin != tata)
        {
            if(nivel[vecin])
            {
                viz[nod] = min(viz[nod],nivel[vecin]);
            }
            else
            {
                dfs(vecin,nod);
                viz[nod] = min(viz[nod],viz[vecin]);
                if(nivel[nod] <= viz[vecin])
                {
                    componenta_biconexa.clear();
                    while(s.top() != vecin)
                    {
                        componenta_biconexa.push_back(s.top());
                        s.pop();
                    }
                    componenta_biconexa.push_back(s.top());
                    s.pop();
                    componenta_biconexa.push_back(nod);
                    componente_biconexe.push_back(componenta_biconexa);
                }

            }
        }
    }
}

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