#include <bits/stdc++.h>

const std :: string FILENAME = "biconex";

std :: ifstream in (FILENAME + ".in");

std :: ofstream out (FILENAME + ".out");

const int NMAX = 1e5 + 5;

int n;

int m;

int x;

int y;

int cnt;

int tin[NMAX];

int low[NMAX];

std :: vector <int> v[NMAX];

std :: bitset <NMAX> visited;

std :: stack <int> s;

std :: vector <int> comp;

std :: vector <std :: vector <int>> comps;

void dfs(int nod)
{
    tin[nod] = low[nod] = cnt ++;

    s.push(nod);

    for(int i : v[nod])
    {
        if(visited[i] == false)
        {
            visited[i] = true;

            dfs(i);

            low[nod] = std :: min(low[nod], low[i]);

            if(low[i] >= tin[nod])
            {
                comp.clear();

                while(s.top() != i)
                {
                    comp.push_back(s.top());

                    s.pop();
                }

                comp.push_back(s.top());

                s.pop();

                comp.push_back(nod);

                comps.push_back(comp);
            }
        }
        else
        {
            low[nod] = std :: min(low[nod], tin[i]);
        }
    }
}

int main()
{

    in >> n >> m;

    for(int i = 1; i <= m; i ++)
    {
        in >> x >> y;

        v[x].push_back(y);

        v[y].push_back(x);
    }

    dfs(1);

    out << comps.size() << '\n';

    for(int i = 0; i < comps.size(); i ++)
    {
        std :: sort(comps[i].begin(), comps[i].end());

        for(int j : comps[i])
        {
            out << j << " ";
        }

        out << '\n';
    }

    return 0;
}