#include <fstream>
#include <stack>
#include <vector>
#include <algorithm>
const int NMAX=100005;

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

vector <int> v[NMAX], cb[NMAX];
int low[NMAX], in[NMAX];
stack <pair<int, int>> st;
int n, m, nrc;

void dfs(int, int);
void prnt(int, int);

int main()
{
    int a, b, i;
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1, 1);
    fout<<nrc<<'\n';
    for(i=1; i<=nrc; i++)
    {
        sort(cb[i].begin(), cb[i].end());
        cb[i].erase(unique(cb[i].begin(), cb[i].end()), cb[i].end());
        for(auto i:cb[i]) fout<<i<<' ';
        fout<<'\n';
    }
    return 0;
}

void dfs(int nod, int lvl)
{
    in[nod]=low[nod]=lvl;
    for(auto i:v[nod])
    {
        if(!in[i])
        {
            st.push({nod, i});
            dfs(i, lvl+1);
            low[nod]=min(low[nod], low[i]);
            if(low[i]>=in[nod]) prnt(nod, i);
        }
        else low[nod]=min(low[nod], in[i]);
    }
}

void prnt(int a, int b)
{
    nrc++;
    int aa, bb;
    do
    {
        aa=st.top().first;
        bb=st.top().second;
        cb[nrc].push_back(aa);
        cb[nrc].push_back(bb);
        st.pop();
    }while(aa!=a || bb!=b);
}