#include <fstream>
#include <vector>
#define pb push_back
#define nMax 100005
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
vector<int> G[nMax], Sol[nMax], stck;
int n, m, Lev[nMax], Low[nMax], nrcbc;
void read()
{
    int a, b;
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        fin>>a>>b;
        G[a].pb(b);
        G[b].pb(a);
    }
}
void tarjan(int node, int tata)
{
    Lev[node]=Lev[tata]+1;
    Low[node]=Lev[node];
    stck.pb(node);
    for(vector<int>::iterator it=G[node].begin();it!=G[node].end();it++)
    {
        int fiu=*it;
        if(fiu==tata)
            continue;
        if(Lev[fiu]!=0)
            Low[node]=min(Low[node], Low[fiu]);
        else
        {
            tarjan(fiu, node);
            Low[node]=min(Low[node], Low[fiu]);
            if(Low[fiu]>=Lev[node])
            {
                int son;
                nrcbc++;
                Sol[nrcbc].pb(node);
                do
                {
                    son=stck.back();
                    Sol[nrcbc].pb(son);
                    stck.pop_back();
                }
                while(fiu!=son);
            }
        }
    }
}
void solve()
{
    for(int i=1;i<=n;i++)
        if(Lev[i]==0)
            tarjan(i, 0);
}
void write()
{
    fout<<nrcbc<<'\n';
    for(int i=1;i<=nrcbc;i++)
    {
        for(vector<int>::iterator it=Sol[i].begin();it!=Sol[i].end();it++)
            fout<<*it<<" ";
        fout<<'\n';
    }
}
int main()
{
    read();
    solve();
    write();
    return 0;
}