#include <iostream>
#include<vector>
#include<fstream>
#include<deque>
using namespace std;
int n,m;
deque <pair <int, int> > ms;
vector<vector<int> > graph;
vector<bool> visited;
vector< vector<int> > rez;
void dfs(int vertex)
{
    if(vertex<0||vertex>n-1)
        return;
    vector<int> s;
    int element;
    unsigned int i;
    bool found;
    s.push_back(vertex);
    visited[vertex]=true;
    while(!s.empty())
    {
        element=s.back();
        found=false;
        for(i=0;i<graph[element].size()&&!found;i++)
        {
            if(!visited[graph[element][i]])
            {
                found=true;
            }
        }
        if(found)
        {
            i--;
            ms.push_back(make_pair(element,graph[element][i]));
            s.push_back(graph[element][i]);
            visited[graph[element][i]]=true;

        }
        else
        {
            s.pop_back();
        }
    }
}
int main()
{
    ifstream f("biconex.in");
    ofstream g("biconex.out");
    int nr=0;
    f>>n>>m;
    graph.resize(n);
    visited.resize(n,false);
    int x,y;
    for(int i=0;i<m;i++)
    {
        f>>x>>y;
        x--;
        y--;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    for(int i=0;i<visited.size()&&i<n;i++)
    {
        if(!visited[i])
        {
            dfs(i);
        }
    }
    int ok=0;
    for(int i=0;i<ms.size();i++)
    {
        for(int j=i+1;j<ms.size();j++)
        {
            bool found=false;
            for(int k=0;k<graph[ms[j].second].size()&&!found==true;k++)
            {
                if(graph[ms[j].second][k]==ms[i].first)
                    found=true;
            }
            if(found==true)
            {
                vector<int> row;
                for(int k=i;k<=j;k++)
                {
                    row.push_back(ms[k].first+1);
                }
                row.push_back(ms[j].second+1);
                rez.push_back(row);
                ok=1;
               // nr++;
                i=j;
                break;
            }
        }
        if(ok==0)
        {
            vector<int> row;
            row.push_back(ms[i].first+1);
            row.push_back(ms[i].second+1);
            rez.push_back(row);
            //nr++;
        }
        else
            ok=0;
    }
   // g<<nr<<"\n";
   g<<rez.size()<<"\n";
    for(int i=0;i<rez.size();i++)
    {
        for(int j=0;j<rez[i].size();j++)
            g<<rez[i][j]<<" ";
        g<<"\n";
    }
    f.close();
    g.close();
    return 0;
}