#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
const int N=1e5+1;
vector<int> v[N];
int nivel[N],nma[N];
stack<int> stiv;
int root;
int k=0;
vector<int> comp[N];
void dfs(int nod,int tata)
{
    int nod2;
    nma[nod]=nivel[nod]=nivel[tata]+1;
    stiv.push(nod);
    for(int i=0;i<v[nod].size();i++)
    {
        nod2=v[nod][i];
        if(nod2!=tata)
        {
            if(nivel[nod2])///am trecut prin el deja
                nma[nod]=min(nma[nod],nivel[nod2]);
            else
            {
                dfs(nod2,nod);
                nma[nod]=min(nma[nod],nma[nod2]);
                //if(nivel[nod]<=nma[nod2] && nod!=root) -> nod critic
                //if(nivel[nod]<nma[nod2]) -> (nod,nod2) -> punte
                if(nivel[nod]<=nma[nod2])
                {
                    k++;
                    while(stiv.top()!=nod2)
                    {
                        comp[k].push_back(stiv.top());
                        stiv.pop();
                    }
                    comp[k].push_back(nod2);
                    stiv.pop();
                    comp[k].push_back(nod);
                }
            }
        }
    }
}
int main()
{
    int n,m,i,x,y,j;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(!nivel[i]){
            root=i;
            dfs(i,0);
        }
    fout<<k<<'\n';
    for(i=1;i<=k;i++)
    {
        for(j=0;j<comp[i].size();j++)
            fout<<comp[i][j]<<" ";
        fout<<'\n';
    }
    return 0;
}