#include <bits/stdc++.h>

using namespace std;

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

const int nmax = 100005;
int n, m;
vector <int> g[nmax];
int niv[nmax], low[nmax];
int viz[nmax];

inline void read()
{
    fin >> n >> m;
    while (m--)
    {
        int a, b;
        fin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
}

int cnt;
stack <int> st;
vector <int> sol[nmax];

inline void dfs(int nod)
{
    st.push(nod);
    viz[nod] = 1;
    low[nod] = niv[nod];
    for (unsigned int i = 0; i < g[nod].size(); i++)
    {
        int vecin = g[nod][i];
        if (viz[vecin])
        {
            low[nod] = min(low[nod], niv[vecin]);
            continue;
        }
        niv[vecin] = niv[nod] + 1;
        dfs(vecin);
        low[nod] = min(low[nod], low[vecin]);
        if (niv[nod] <= low[vecin]) //avem o comp
        {
            sol[++cnt].push_back(nod);
            int x;
            do
            {
                x = st.top();
                st.pop();
                sol[cnt].push_back(x);
            }while (x != vecin);
        }
    }
}

inline void solve()
{
    for (int i = 1; i <= n; i++)
        if (!viz[i])
            niv[i] = 1, dfs(i);
    fout << cnt << "\n";
    for (int i = 1; i <= cnt; i++)
    {
        for (int j : sol[i])
            fout << j << " ";
        fout << "\n";
    }
}

int main()
{
    read();
    solve();
    return 0;
}