#include <fstream>
#include <cstring>
#include <algorithm>
#include <stack>
#include <vector>
#include <utility>
#include <set>

#define mp make_pair
#define pb push_back
#define f first
#define s second
#define DIM 100009

using namespace std;
ofstream out("biconex.out");

int n , m  , nr;

int dfn[DIM] , low[DIM];

vector < int > G[DIM];
typedef vector < int >::iterator IT;

set < int  >C[DIM];
typedef set < int >::iterator JT;

stack < pair < int , int > >S;


void read();
void biconex( int x , int y );
void dfs( int , int  , int );
void wrs();


int main()
{

    read();
    dfs(1,0,0);
    wrs();

    return 0;

}

void read()
{

    ifstream in("biconex.in");

    in >> n >> m;

    for( int x , y ; m ; --m )
    {

        in >> x >> y;

        G[x].pb(y);
        G[y].pb(x);

    }

    for( int i=1 ; i<=n ; i++)
        dfn[i] = -1;

}

void dfs( int start , int tata , int number )
{

    dfn[start] = low[ start] = number;

    for( IT i = G[start].begin() ; i!=G[start].end() ; ++i )
    {

        if( *i == tata )
            continue;

        if( dfn[*i] == - 1 )
        {

            S.push( mp ( start , *i ));
            dfs(*i,start,number+1);

            low[start] = min ( low[start] , low[*i] );

            if( low[*i] >= dfn[start] )
                biconex(start,*i);

        }
        else
            low[start] = min ( low[start] , dfn[*i] );


    }

}

void biconex( int x , int y )
{

    ++nr;
    int ii , jj;

    do
    {

        ii = S.top().f;
        jj = S.top().s;

        S.pop();
        C[nr].insert(ii);
        C[nr].insert(jj);

    }
    while( ii != x || jj != y );

}

void wrs()
{

    out << nr << '\n';

    for( int i = 1 ; i <= nr; ++i )
    {

        for( JT j = C[i].begin() ; j!=C[i].end(); ++j)
            out << *j << " ";

        out << '\n';

    }


}