#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>

using namespace std;

int n;
int dfn[100005], low[100005];
vector <int> a[100005];
vector <vector <int> > sol;
stack <pair <int, int> > st;

void afisare(int x, int y)
{
    int X, Y;
    vector <int> aux;
    do
    {
        X = st.top().first; Y = st.top().second;
        st.pop();
        aux.push_back(X); aux.push_back(Y);
    } while(X != x && Y != y);
    sol.push_back(aux);
}

void Biconex(int nc, int pnc, int num)
{
    int x;
    vector<int>::iterator it;
    dfn[nc] = low[nc] = num;
    for(it = a[nc].begin(); it != a[nc].end(); ++it)
    {
        if(*it == pnc) continue;
        if(dfn[*it] == -1)
        {
            st.push(make_pair(nc, *it));
            Biconex(*it, nc, num+1);
            low[nc] = min(low[nc], low[*it]);
            if(low[*it] >= dfn[nc]) afisare(nc, *it);
        }
        else low[nc] = min(low[nc], dfn[*it]);
    }
}

int main()
{
    int m;
    ifstream fin("biconex.in");
    fin >> n >> m;
    for(int i = 1, x, y; i <= m; ++i)
    {
        fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    fin.close();

    for(int i = 1; i <= n; ++i) dfn[i] = -1;
    Biconex(1, 0, 0);

    ofstream fout("biconex.out");
    fout << sol.size() << '\n';
    for(int i = 0; i < sol.size(); ++i)
    {
        sort(sol[i].begin(), sol[i].end());
        sol[i].erase(unique(sol[i].begin(), sol[i].end()), sol[i].end());
        for(int j = 0; j < sol[i].size(); ++j) fout << sol[i][j] << " ";
        fout << '\n';
    }
    fout.close();
    return 0;
}