#include<cstdio>
#include<vector>
#include<algorithm>
#include<cstring>
using namespace std;
vector<int> G[100005];
int n,m,i,x,y,timp,root,rootChildren,nrsol;
int low[100005],discover[100005];
bool articulation[100005];
struct latura
{
  int x,y;
} aux1;
vector<latura> st;
vector<int> sol[100005];

void dfs(int x,int parent)
{
    timp++;
    low[x]=discover[x]=timp;
    for(int i=0;i<G[x].size();i++)
    {
        if(G[x][i]==parent) continue;
        if(discover[G[x][i]])
        {
            low[x]=min(low[x],discover[G[x][i]]);
        }
        else
        {
            if(x==root) rootChildren++;
            aux1.x=x;
            aux1.y=G[x][i];
            st.push_back(aux1);
            dfs(G[x][i],x);
            if(low[G[x][i]]>=discover[x])
            {
                nrsol++;
                while(st.back().x!=x and st.back().y!=x)
                {
                    sol[nrsol].push_back(st.back().y);
                    st.pop_back();
                }
                sol[nrsol].push_back(st.back().y);
                sol[nrsol].push_back(st.back().x);
                if(!st.empty()) st.pop_back();
            }
            if(low[G[x][i]]>=low[x])
            {
                articulation[x]=true;
            }
            low[x]=min(low[x],low[G[x][i]]);
        }
    }
    //st.pop_back();
}
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    scanf("%d %d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d %d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
    {
        if(discover[i]==0)
        {
            root=i;
            rootChildren=0;
            dfs(i,-1);
            if(rootChildren>=2)
                articulation[i]=true;
        }
    }
    printf("%d\n",nrsol);
    for(int i=1;i<=nrsol;i++)
    {
        for(int j=0;j<sol[i].size();j++)
            printf("%d ",sol[i][j]);
        printf("\n");
    }
    return 0;
}