#include<bits/stdc++.h>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
vector<int>v[100001];
vector<int>cbc[100001];
stack<int>stiva;
int tmin[100001],t[100001],timp,ncbc;
void adauga_cbc(int x,int y)
{
    ncbc++;
    while(stiva.top()!=y)
    {
        cbc[ncbc].push_back(stiva.top());
        stiva.pop();
    }
    cbc[ncbc].push_back(y);
    cbc[ncbc].push_back(x);
    stiva.pop();
}
void dfs(int x,int tata)
{
    tmin[x]=t[x]=++timp;
    stiva.push(x);
    for(auto q:v[x])
    {
        if(t[q]==0)
        {
            dfs(q,x);
            tmin[x]=min(tmin[x],tmin[q]);
            if(tmin[q]>=t[x])
            {
                adauga_cbc(x,q);
            }
        }
        else if(q!=tata)
        {
            tmin[x]=min(tmin[x],t[q]);
        }
    }
}

int main()
{
    int n,m;
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        fin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for(int i=1;i<=n;i++)
    {
        if(t[i]==0)
            dfs(i,0);
    }
    fout<<ncbc<<"\n";
    for(int i=1;i<=ncbc;i++)
    {
        for(auto q:cbc[i])
            fout<<q<<" ";
        fout<<"\n";
    }
    fin.close();
    fout.close();
    return 0;
}