#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>
using namespace std;
ifstream si("biconex.in");
ofstream so("biconex.out");
bitset<100005> viz;
vector<int> v[100005];
vector< vector<int> > comp;
vector< pair<int,int> > q;
int niv[100005],nmin[1000005];
void combin(int a,int b)
{
    vector<int> aux;
    int x,y;
    do
    {
        x=q.back().first;
        y=q.back().second;
        q.pop_back();
        aux.push_back(y);
    }
    while(a!=x||b!=y);
    aux.push_back(a);
    comp.push_back(aux);
}

void dfs(int nod,int lev)
{
    viz[nod]=1;
    niv[nod]=nmin[nod]=lev;
    vector<int>::iterator i;
    for(i=v[nod].begin();i!=v[nod].end();i++)
        if(!viz[*i])
        {
            q.push_back({nod,*i});
            dfs(*i,lev+1);
            nmin[nod]=min(nmin[nod],nmin[*i]);
            if(nmin[*i]>=niv[nod])
                combin(nod,*i);
        }
        else
            nmin[nod]=min(nmin[nod],niv[*i]);
}

int main()
{
    int n,m,x,y;
    si>>n>>m;
    int i;
    for(i=1;i<=m;++i)
    {
        si>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;++i)
        if(!viz[i])
            dfs(i,0);
    m=comp.size();
    so<<m<<'\n';
    int j;
    for(i=0;i<m;++i)
    {
        for(j=0;j<comp[i].size();++j)
            so<<comp[i][j]<<' ';
        so<<'\n';
    }
    return 0;
}