#include <fstream>
#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
const int NMAX=1e5+5;
int n, m, i, j, depth[NMAX], x, y, nma[NMAX], nrc;
vector <int> v[NMAX];
bool viz[NMAX];
vector <int> biconex[NMAX];
stack <int> st;
void dfs(int nod, int par)
{
    viz[nod]=1;
    depth[nod]=depth[par]+1;
    nma[nod]=depth[nod];
    st.push(nod);
    for(auto i: v[nod])
        if(i!=par)
        {
            if(viz[i])
                nma[nod]=min(nma[nod], depth[i]);
            else
            {
                dfs(i, nod);
                nma[nod]=min(nma[nod], nma[i]);
                if(depth[nod]<=nma[i])
                {
                    nrc++;
                    int x;
                    do
                    {
                        x=st.top();
                        st.pop();
                        biconex[nrc].push_back(x);
                    }
                    while(x!=i);

                    biconex[nrc].push_back(nod);
                }
            }
        }
}
int main()
{
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1, -1);
    fout<<nrc<<'\n';
    for(i=1; i<=nrc; i++)
    {
        for(auto j: biconex[i])
            fout<<j<<" ";
        fout<<'\n';
    }

    return 0;
}