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

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

vector <int> v[100005];

int lvl[100005], low[100005], pas;

stack <int> st;

vector < vector <int> > elem;

vector <int> aux;

void dfs(int node, int dad)
{
    lvl[node] = low[node] = ++pas;

    st.push(node);

    for(int i = 0; i < v[node].size(); i++)
        if(v[node][i] != dad)
    {
        if(lvl[v[node][i]] != 0)
        {
            low[node] = min(low[node], lvl[v[node][i]]);
            continue;
        }

        dfs(v[node][i], node);

        low[node] = min(low[node], low[v[node][i]]);

        if(low[v[node][i]] >= lvl[node])
        {
            vector <int> aux;

            while(st.top() != node)
            {
                aux.push_back(st.top());
                st.pop();
            }

            aux.push_back(node);

            elem.push_back(aux);
        }
    }
}


int main()
{
    int N, M, Q;

    fin >> N >> M;

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

        fin >> x >> y;

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

    for(int i = 1; i <= N; i++)
        if(lvl[i] == 0)
            dfs(i, 0);

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

    for(int i = 0; i < elem.size(); i++)
    {
        for(int j = 0; j < elem[i].size(); j++)
            fout << elem[i][j] << " ";
        fout << '\n';
    }
    return 0;
}