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

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

vector<vector<int> > G;
stack<pair<int, int> > s;
vector<vector<int> > comp;
vector<int> c;
int niv[100001];
int Lmin[100001];
bool sel[100001];
int n, m, x1, x2;

void Df(int x, int t, int nv);
void Write();


int main()
{

    is >> n >> m;

    G.resize(n + 1);
    for(int i = 1; i <= m; ++i)
    {
        is >> x1 >> x2;
        G[x1].push_back(x2);
        G[x2].push_back(x1);

    }

    Df(1, 0, 0);
    Write();

    is.close();
    os.close();
    return 0;
}


void Df(int x, int t, int nv)
{
    Lmin[x] = nv;
    niv[x] = nv;
    sel[x] = true;
    for(const int& y: G[x])
    {
        if(y == t)
            continue;
        if(!sel[y])
        {
            s.push({x, y});
            Df(y, x, nv + 1);
            Lmin[x] = min(Lmin[x], Lmin[y]);
            if(Lmin[y] >= niv[x])
            {
                c.clear();
                while(true)
                {
                    x1 = s.top().first;
                    x2 = s.top().second;
                    s.pop();
                    c.push_back(x1);
                    c.push_back(x2);
                    if(x1 == x && x2 == y)
                        break;
                }
                comp.push_back(c);
            }
        }
        else
            Lmin[x] = min(Lmin[x], niv[y]);
    }

}


void Write()
{
    os << comp.size() << '\n';
    for(auto & c : comp)
    {
        sort(c.begin(), c.end());
        c.erase(unique(c.begin(), c.end()), c.end());
        for(auto & x : c)
            os << x << ' ';
        os << '\n';
    }

}