#include <iostream>
#include <fstream>
#include <set>
#include <stack>
#include <vector>
#include <algorithm>
#define MAX_N 100001
using namespace std;
vector<int> adj[MAX_N],nv,L;
vector< vector<int> > sol;
stack< pair<int,int> > st;
int n;
void read()
{
    int m,x,y;
    ifstream f("biconex.in");
    f>>n>>m;
    for(;m;m--)
    {
        f>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    f.close();
}
void cache_bc(const int x, const int y)
{
    vector<int> c;
    int tx,ty;
    do
    {
        tx=st.top().first;
        ty=st.top().second;
        st.pop();
        c.push_back(tx),c.push_back(ty);
    }while(tx!=x||ty!=y);
    sol.push_back(c);
}
void DF(const int n, const int tn, const int nb)
{
    vector<int>::iterator it;
    nv[n]=L[n]=nb;
    for(it=adj[n].begin();it!=adj[n].end();it++)
    {
        if(*it==tn)continue;
        if(nv[*it]==-1)
        {
            st.push(make_pair(n,*it));
            DF(*it,n,nb+1);
            L[n]=min(L[n],L[*it]);
            if(L[*it]>=nv[n])
                cache_bc(n,*it);
        }
        else L[n]=min(L[n],nv[*it]);
    }
}
void write()
{
    ofstream g("biconex.out");
    g<<sol.size()<<'\n';
    for(size_t 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(size_t j=0;j<sol[i].size();j++)
            g<<sol[i][j]<<" ";
        g<<'\n';
    }
    g.close();
}
int main()
{
    read();
    nv.resize(n+1),nv.assign(n+1,-1);
    L.resize(n+1);
    DF(1,0,0);
    write();
    return 0;
}