#include <bits/stdc++.h>

using namespace std;

#define f first
#define s second

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

int i,j,n,m,k,mini[100010],idx[100010],ans,x,y,a,b;
vector<int> G[100001],sol[100010];
stack< pair<int,int> > st;

void DF( int nod, int father )
{
    idx[ nod ] = mini[ nod ] = idx[ father ] + 1;
    for( auto it : G[ nod ] )
    {
        if( it != father )
        {
            if( !idx[ it ] )
            {
                st.push( {it,nod} );
                DF( it , nod );
                if( mini[ it ] >= idx[ nod ] )
                {
                    a = 0;
                    b = 0;
                    ++ans;
                    do
                    {
                        a = st.top().f;
                        b = st.top().s;
                        sol[ ans ].push_back( a );
                        st.pop();
                    }while( b != nod );
                    sol[ ans ].push_back( nod );
                }
            }
            mini[ nod ] = min( mini[ nod ] , mini[ it ] );
        }
    }
}

int main()
{

    fin>>n>>m;
    for( i = 1 ; i <= m ; i++ )
    {
        fin>>x>>y;
        G[ x ].push_back( y );
        G[ y ].push_back( x );
    }
    for( i = 1 ; i <= n ; i++ )
    {
        if( !idx[ i ] )
            DF( i , 0 );
    }
    fout<<ans<<'\n';
    for( i = 1 ; i <= ans ; i++ )
    {
        for( auto it : sol[ i ] )
            fout<<it<<' ';
        fout<<'\n';
    }

return 0;
}