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

const int NMAX = 100005;

int n, m;
vector<int> la[NMAX];

int bcc_cnt = 0;
set<int> bcc[NMAX];

int disc[NMAX];
int low[NMAX];
int parent[NMAX];
int t = 1;

stack<pair<int, int>> stiva;

void dfs(int nod)
{
    disc[nod] = low[nod] = t++;
    for (auto &c: la[nod])
    {
        if (c == parent[nod])
            continue;
        if (!disc[c])
        {
            parent[c] = nod;
            stiva.push(make_pair(nod, c));
            dfs(c);
            low[nod] = min(low[nod], low[c]);

            if (disc[nod] <= low[c])
            {
                ++bcc_cnt;
                while (stiva.top() != make_pair(nod, c))
                {
                    bcc[bcc_cnt].insert(stiva.top().first);
                    bcc[bcc_cnt].insert(stiva.top().second);
                    stiva.pop();
                }
                bcc[bcc_cnt].insert(stiva.top().first);
                bcc[bcc_cnt].insert(stiva.top().second);
                stiva.pop();
            }
        }
        else if (disc[c] < disc[nod])
        {
            stiva.push(make_pair(nod, c));
            low[nod] = min(low[nod], disc[c]);
        }
    }
}

int main()
{
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);

    cin >> n >> m;
    for (int i = 1; i <= m; ++i)
    {
        int u, v;
        cin >> u >> v;
        la[u].push_back(v);
        la[v].push_back(u);
    }
    dfs(1);
    cout << bcc_cnt << '\n';
    for (int i = 1; i <= bcc_cnt; ++i)
    {
        for (auto &x : bcc[i])
            cout << x << ' ';
        cout << '\n';
    }
}