#include<stdio.h>
#include<algorithm>
#include<vector>
#define MAXV 100000
#define MAXE 200000

void dfs(int nod);

FILE*fin,*fout;

int lista[MAXV+1],next[MAXE+1],val[MAXE+1],k=0;
int st[MAXE+1],ult=-1;

std::pair<int,int> edge[MAXE+1];
std::vector<std::vector<int>> sol;
std::vector<int> partial_sol;
int level[MAXV+1],ind[MAXV+1];
int tata[MAXV+1];
int index=0;
int main()
{
    fin=fopen("biconex.in","r");
    fout=fopen("biconex.out","w");

    int V,E;


    fscanf(fin,"%d%d",&V,&E);

    for(int i=1; i<=E; i++)
    {
        int x,y;
        fscanf(fin,"%d%d",&x,&y);
        next[++k]=lista[y];
        val[k]=x;
        lista[y]=k;
        next[++k]=lista[x];
        val[k]=y;
        lista[x]=k;
    }
    dfs(1);
    fprintf(fout,"%d\n",sol.size());
    for(int i=0;i<sol.size();i++)
    {
        for(int j=0;j<sol[i].size();j++)
        {
            fprintf(fout,"%d ",sol[i][j]);
        }
        fprintf(fout,"\n");
    }
    fclose(fin);
    fclose(fout);
}

void dfs(int nod)
{
    ind[nod]=++index;
    level[nod]=index;
    int p=lista[nod];
    while(p!=0)
    {
        int vec=val[p];
        if(ind[vec]==0)
        {
            st[++ult]=p;
            tata[vec]=nod;
            dfs(vec);
            level[nod]=std::min(level[nod],level[vec]);
            if(ind[nod]<=level[vec])
            {
                partial_sol.clear();
                while(ult>0  && st[ult]!=p)
                {
                    partial_sol.push_back(val[st[ult]]);
                    //printf("%d ",val[st[ult]]);
                    ult--;
                }
                partial_sol.push_back(val[p]);
                //printf("%d ",val[p]);
                ult--;
                partial_sol.push_back(nod);
                //printf("%d\n",nod);
                sol.push_back(partial_sol);
            }

        }
        else if(tata[nod]!=vec)
        {
            level[nod]=std::min(level[nod],ind[vec]);
        }
        p=next[p];
    }

}