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

///#include <tryhardmode>
///#include <GODMODE::ON>

using namespace std;

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

const int NMAX=1e5+5;

stack<int>stiva;

vector<int>v[NMAX];
vector<int>cbc[NMAX];

int ti[NMAX];
int tm[NMAX];
int total;
int kon;

void dfs(int p,int tata)
{
    ti[p]=++kon;
    tm[p]=ti[p];
    stiva.push(p);
    for(auto i:v[p])
    {
        if(i!=tata)
        {
            if(!ti[i])
            {
                dfs(i,p);
                tm[p]=min(tm[p],tm[i]);
                if(tm[i]>=ti[p])
                {
                    total++;
                    while(stiva.top()!=i)
                    {
                        cbc[total].push_back(stiva.top());
                        stiva.pop();
                    }
                    cbc[total].push_back(stiva.top());
                    stiva.pop();
                    cbc[total].push_back(p);
                }
            }
            else
                tm[p]=min(tm[p],ti[i]);
        }
    }
}

int main()
{
    int n,m,i,j,x,y;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
    {
        if(!ti[i])
            dfs(i,0);
    }
    fout<<total<<"\n";
    for(i=1;i<=total;i++)
    {
        for(auto j:cbc[i])
            fout<<j<<" ";
        fout<<"\n";
    }
    return 0;
}