#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>
using namespace std;

ifstream is("biconex.in");
ofstream os("biconex.out");

int n, m;
vector<vector<int>> g, cb;
vector<int> t, niv, nivm, comp;
stack<pair<int, int>> s;

void Read();
void Solve(int nod);
void Make(int x, int y);
void Write();

int main()
{
    Read();
    niv[1] = nivm[1] = 1;
    Solve(1);
    Write();
    is.close();
    os.close();
    return 0;
}

void Solve(int nod)
{
    for ( const auto& nodv : g[nod] )
    {
        if ( t[nod] == nodv )
            continue;
        if ( !niv[nodv] )
        {
            niv[nodv] = nivm[nodv] = niv[nod] + 1;
            t[nodv] = nod;
            s.push(make_pair(nod, nodv));
            Solve(nodv);
            nivm[nod] = min(nivm[nod], nivm[nodv]);
            if ( nivm[nodv] >= niv[nod] )
                Make(nod, nodv);
        }
        else
            nivm[nod] = min(nivm[nod], niv[nodv]);
    }
}

void Make(int x, int y)
{
    comp.clear();
    int xx, yy;
    do
    {
        comp.push_back(xx = s.top().first);
        comp.push_back(yy = s.top().second);
        s.pop();
    } while ( x != xx && y != yy );
    sort(comp.begin(), comp.end());
    comp.erase(unique(comp.begin(), comp.end()), comp.end());
    cb.push_back(comp);
}

void Write()
{
    os << cb.size() << "\n";
    for ( const auto& i : cb )
    {
        for ( const auto& j : i )
            os << j << " ";
        os << "\n";
    }
}

void Read()
{
    is >> n >> m;
    g.resize(n + 1);
    t.resize(n + 1);
    niv.resize(n + 1);
    nivm.resize(n + 1);
    int n1, n2;
    for ( int i = 1; i <= m; ++i )
    {
        is >> n1 >> n2;
        g[n1].push_back(n2);
        g[n2].push_back(n1);
    }
}