#include <fstream>
#include <vector>
#include <deque>

using namespace std;

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

const int NMAX = 100005;

int N, M;
vector <int> Ad[NMAX];

deque <int> S;

int disc[NMAX];
int low[NMAX];
int t;
int nr_comp;

vector <int> Comp[NMAX];

void Read()
{
    fin >> N >> M;

    int x, y;

    for( int i = 1; i <= M; ++i )
    {
        fin >> x >> y;

        Ad[x].push_back( y );
        Ad[y].push_back( x );
    }

    fin.close();
}

void Dfs( int nod, int parent )
{
    disc[nod] = low[nod] = ++t;

    int w;

    for( int i = 0; i < Ad[nod].size(); ++i )
    {
        w = Ad[nod][i];

        if( w == parent ) continue;

        if( disc[w] ) low[nod] = min( low[nod], disc[w] );
        else
        {
            S.push_back( w );

            Dfs( w, nod );

            low[nod] = min( low[nod], low[w] );

            if( low[w] >= disc[nod] )
            {
                ++nr_comp;

                S.push_back( nod );

                while( !S.empty() && S.back() != w )
                {
                    Comp[nr_comp].push_back( S.back() );
                    S.pop_back();
                }

                if( !S.empty() )
                {
                    Comp[nr_comp].push_back( S.back() );
                    S.pop_back();
                }
            }
        }
    }
}

void Do()
{
    Dfs( 1, 0 );

    fout << nr_comp << '\n';

    for( int i = 1; i <= nr_comp; ++i )
    {
        for( int j = 0; j < Comp[i].size(); ++j )
            fout << Comp[i][j] << ' ';

        fout << '\n';
    }

}

int main()
{
    Read();
    Do();

    return 0;
}