#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>
#define maxN 100005

using namespace std;

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

int n, m, t, low[maxN], timp[maxN], parent[maxN], art[maxN];
vector <int> G[maxN];
vector <vector <int> > C;
stack <pair <int, int> > st;

void add (int x, int y) {
    vector <int> comp;
    int tx = 0, ty = 0;
    while (tx != x or ty != y) {
        tx = st.top().first , ty = st.top().second;
        st.pop();
        comp.push_back(tx), comp.push_back(ty);
    }
    C.push_back(comp);
}

void dfs (int nod) {
    int childs = 0;
    low[nod] = timp[nod] = ++t;
    int size = G[nod].size();
    for (int i = 0; i < size; ++i) {
        int u = G[nod][i];
        if (timp[u] == 0) {
            childs++;
            parent[u] = nod;
            st.push({nod, u});
            dfs(u);
            low[nod] = min(low[nod], low[u]);

            /*if (parent[nod] == 0 and childs > 1) {
                art[nod]++;
                add(nod, u);
            }*/
            if (low[u] >= timp[nod]) {
                art[nod]++;
                add(nod, u);
            }
        }
        else {
            low[nod] = min(low[nod], timp[u]);
        }
    }
}

int main () {
    fin >> n >> m;
    int x, y;
    for (int i = 1; i <= m; ++i) {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1);
    /*for (int i = 1; i <= n; ++i) {
        if (art[i])
            fout << i << " ";
    }*/
    fout << C.size() << '\n';
    int size = C.size();
    for (int i = 0; i < size; ++i) {
        sort(C[i].begin(), C[i].end());
        C[i].erase(unique(C[i].begin(), C[i].end()), C[i].end());
        int size1 = C[i].size();
        for (int j = 0; j < size1; ++j) {
            fout << C[i][j] << " ";
        }
        fout << '\n';
    }
}