#include <bits/stdc++.h>
using namespace std;

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

const int N = 1e5 + 5;

int n, m;

vector <int> g[N];

bool articulatie[N];

int t_min[N], t_in[N];

int timer;

vector <vector <int>> cbc;
stack <int> stiva;

void adauga(int x, int y, vector <int> &v)
{
    while(stiva.top() != y)
    {
        v.push_back(stiva.top());
        stiva.pop();
    }
    v.push_back(y);
    stiva.pop();
    v.push_back(x);
}

void dfs(int node, int par)
{
    t_min[node] = t_in[node] = ++timer;
    stiva.push(node);
    int nr_fii = 0;
    for(auto fiu:g[node])
    {
        if(fiu == par)
            continue;
        if(t_in[fiu] == 0)
        {
            dfs(fiu, node);
            nr_fii++;
            t_min[node] = min(t_min[node], t_min[fiu]);
            if(t_min[fiu] >= t_in[node])
            {
                articulatie[node] = true;
                vector <int> c;
                adauga(node, fiu, c);
                cbc.push_back(c);
            }
        }
        else
        {
            t_min[node] = min(t_min[node], t_in[fiu]);
        }
    }
    if(par == 0 && nr_fii > 1)
    {
        articulatie[node] = true;
    }
}

int main()
{
    in >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        int x, y;
        in >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for(int i = 1; i <= n; i++)
    {
        if(t_in[i] == 0)
        {
            dfs(i, 0);
        }
    }
    out << cbc.size() << '\n';
    for(auto comp:cbc)
    {
        for(auto x:comp)
        {
            out << x << ' ';
        }
        out << '\n';
    }
    return 0;
}