#include <bits/stdc++.h>
using namespace std;

const int NMAX = 1e5 + 1;

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

int N, M;
vector<vector<int>> graph(NMAX, vector<int>());


int low[NMAX], id[NMAX], timer = 0;
stack<int> stivaNoduri;

vector<vector<int>> bcs;


void DFS(int nod, int tata)
{
    id[nod] = low[nod] = ++timer;

    stivaNoduri.push(nod);

    for(auto& fiu : graph[nod])
    {
        if(fiu == tata) continue;

        if(id[fiu] != 0)
        {
            low[nod] = min(low[nod], id[fiu]);
        }
        else
        {
            DFS(fiu, nod);
            low[nod] = min(low[fiu], low[nod]);

            if(id[nod] <= low[fiu])
            {
                bcs.push_back(vector<int>());

                int varf;

                do
                {
                    varf = stivaNoduri.top();
                    bcs.back().push_back(varf);
                    stivaNoduri.pop();

                }while(varf != fiu);

                bcs.back().push_back(nod);
            }
        }
    }

}


int main()
{
    fin >> N >> M;

    for(int i = 1; i <= M; ++i)
    {
        int x, y;
        fin >> x >>y;

        graph[x].push_back(y);
        graph[y].push_back(x);
    }

    DFS(1, -1);

    fout << bcs.size() << '\n';

    for(vector<int>& bc : bcs)
    {
        for(int nod : bc)
        {
            fout << nod << ' ';
        }

        fout << '\n';
    }
}