#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

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

const int MAX=1e5+5;
int n,m,a,b,tmp[MAX],lowtmp[MAX],part[MAX],viz[MAX],timp;
vector < int > v[MAX],sol1,sol2;
vector < pair < int, int > > mch;
vector < vector < int > > bicomp;

void DFS(int nod, int tata)
{
    bool ispart=0;
    int fii=0;
    tmp[nod]=lowtmp[nod]=++timp;
    for(auto vec : v[nod])
    {
        if(vec==tata)
            continue;
        if(!tmp[vec])
        {
            mch.push_back({nod,vec});
            DFS(vec,nod);
            lowtmp[nod]=min(lowtmp[nod],lowtmp[vec]);
            if(tmp[nod]<=lowtmp[vec])
            {
                vector < int > comp;
                do
                {
                    a=mch.back().first;
                    b=mch.back().second;
                    mch.pop_back();
                    comp.push_back(a);
                    comp.push_back(b);
                } while(a!=nod || b!=vec);
                sort(comp.begin(),comp.end());
                comp.erase(unique(comp.begin(),comp.end()),comp.end());
                bicomp.push_back(comp);
            }
        }
        else
            lowtmp[nod]=min(lowtmp[nod],tmp[vec]);
    }
}

int main()
{
    fin >> n  >> m;
    while(m--)
    {
        fin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    DFS(1,0);
    fout << bicomp.size() << '\n';
    for(auto comp : bicomp)
    {
        for(auto elem : comp)
            fout << elem << " ";
        fout << '\n';
    }
    return 0;
}