#include <iostream>
#include <fstream>
#include <stack>
#include <vector>
using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

vector<vector<int>> ma;
stack<int> s;
vector<int> mini,desc;            ///low mini dfn desc
int tot,timp=1;
vector<vector<int>> ra;
vector<int> v;
void dfs(int nod)
{
    mini[nod]=timp;
    desc[nod]=timp;
    s.push(nod);
    ++timp;
    vector<int>::iterator el;
    for(el=ma[nod].begin();el!=ma[nod].end();++el)
    {
        if(desc[*el]==0)
        {
            dfs(*el);
            mini[nod]=min(mini[nod],mini[*el]);
            if(mini[*el]>=desc[nod])
            {
                int x;
                ++tot;
                v.push_back(nod);
                do{
                    x=s.top();
                    s.pop();
                    v.push_back(x);
                }while(x!=*el);
                ra.push_back(v);
                v.clear();
            }
        }
        else
            mini[nod]=min(mini[nod],desc[*el]);
    }
}

int main()
{
    int n,m,x,y;
    fin>>n>>m;
    ma.resize(n+1);
    mini.resize(n+1,0);
    desc.resize(n+1,0);
    for(int k=1;k<=m;k++)
    {
        fin>>x>>y;
        ma[x].push_back(y);
        ma[y].push_back(x);
    }
    dfs(1);
    vector<int>::iterator el;
    vector<vector<int>>::iterator k;
    fout<<tot<<'\n';
    for(k=ra.begin();k!=ra.end();k++)
    {
        for(el=k->begin();el!=k->end();el++)
            fout<<*el<<" ";
        fout<<'\n';
    }
    return 0;
}