#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#define NMAX 100002
using namespace std;

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

vector<int>v[NMAX], afis[NMAX];
stack<pair<int, int> >st;
int tt[NMAX], d[NMAX];
int nr_componente=0;

int DFS(int x)
{
    int i, low, lowV, u;
    d[x]=d[tt[x]]+1;
    low=d[x];
    for(i=0; i<v[x].size(); i++)
    {
        u=v[x][i];
        if(u!=tt[x])
        {
            if(d[u]>0) low=min(low, d[u]);
            else
            {
                tt[u]=x;
                st.push({x, u});
                lowV=DFS(u);
                if(lowV>=d[x]) //am gasit un punct de articulatie
                {
                    nr_componente++;
                    while(st.top().first!=x || st.top().second!=u)
                    {
                        afis[nr_componente].push_back(st.top().second);
                        st.pop();
                    }afis[nr_componente].push_back(st.top().second); afis[nr_componente].push_back(st.top().first);
                    st.pop();
                }
                low=min(low, lowV);
            }
        }
    }
    return low;
}
int main()
{
    int n, m, i, j, x, y;
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    //tt[1]=0;
    DFS(1);
    fout<<nr_componente<<"\n";
    for(i=1; i<=nr_componente; i++)
    {
        for(j=afis[i].size()-1; j>=0; j--)
        {
            fout<<afis[i][j]<<' ';
        }
        fout<<"\n";
    }
}