#include <bits/stdc++.h>

using namespace std;

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

#define nmax 100005

stack<pair<int,int>> st;
vector<vector<int>> sol;
vector<int> g[nmax];
vector<int> bx;

int n, m;
int viz[nmax];
int h[nmax];
int nma[nmax];
int tx = 0, ty = 0;

void rez(int x, int y)
{
    int tx, ty;
    do
    {
        tx = st.top().first;
        ty = st.top().second;
        bx.push_back(tx);
        bx.push_back(ty);
        st.pop();
    }while(tx != x or ty != y);
    sol.push_back(bx);
}

void dfs(int nod, int tata, int nivel)
{
    viz[nod] = 1;
    h[nod] = nivel;
    nma[nod] = nivel;
    for(int i = 0; i < g[nod].size(); ++i)
    {
        int x = g[nod][i];
        if(!viz[x])
        {
            st.push({x, nod});
            dfs(x, nod, nivel + 1);
            nma[nod] = min(nma[nod], nma[x]);
            if(nma[x] >= h[nod])rez(x, nod);
        }
        else if(x != tata)nma[nod] = min(nma[nod], h[x]);
    }
}
int main()
{
    fin >> n >> m;
    int i, j, x, y;
    for(i = 1; i <= m; ++i)
    {
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1, 0, 1);
    fout << sol.size();
    fout << '\n';
    for(unsigned i = 0; i < sol.size(); ++i)
    {
        sort(sol[i].begin(), sol[i].end());
        fout << sol[i][0] << ' ';
        for(unsigned j = 1; j < sol[i].size(); ++j)if(sol[i][j] != sol[i][j - 1])fout << sol[i][j] << ' ';
        fout << '\n';
    }
    return 0;
}