#include <bits/stdc++.h>
#define Dim 100007
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int N,M,dfn[Dim],low[Dim],ans,a,b;
bool viz[Dim];

vector < int > V[Dim],A[Dim];
stack <int> S;

void DFS(int nod)
{
    viz[nod]=1;
    S.push(nod);
    for(unsigned int i=0;i<V[nod].size();i++)
    {
        int vecin=V[nod][i];
        if(!viz[vecin])
        {
        dfn[vecin]=low[vecin]=dfn[nod]+1;
        DFS(vecin);
        if(low[vecin]>=dfn[nod])
        {
            ans++;
            while(S.top()!=vecin)
            {
                A[ans].push_back(S.top());
                S.pop();
            }
            S.pop();
            A[ans].push_back(vecin);
            A[ans].push_back(nod);
        }
        low[nod]=min(low[nod],low[vecin]);
       }
       else low[nod]=min(low[nod],dfn[vecin]);
    }
}

int main()
{
    f>>N>>M;
    for(int i=1;i<=M;i++)
    {
        f>>a>>b;
        V[a].push_back(b);
        V[b].push_back(a);
    }
    for(int i=1;i<=N;i++)
    if(!viz[i]) DFS(i);
    g<<ans<<'\n';
    for(int i=1;i<=ans;i++)
    {
        for(unsigned j=0;j<A[i].size();j++) g<<A[i][j]<<" ";
        g<<'\n';
    }
    return 0;
}