#include <bits/stdc++.h>

using namespace std;

const int NMAX = 1e5;

vector <int> edges[NMAX + 1];
int timp[NMAX + 1];
int minTimp[NMAX + 1];
bool viz[NMAX + 1];
int t = 0;

stack <int> st;

vector <vector <int>> comps;

void dfs( int node, int p = 0 ) {
    timp[node] = minTimp[node] = ++t;
    viz[node] = true;

    st.push( node );
    for ( auto vec : edges[node] ) {
        if ( !viz[vec] ) {
            dfs( vec, node );
            minTimp[node] = min( minTimp[node], minTimp[vec] );

            if ( minTimp[vec] >= timp[node] ) {
                vector <int> comp;
                while ( st.top() != vec ) {
                    comp.push_back( st.top() );
                    st.pop();
                }
                comp.push_back( vec );
                st.pop();
                comp.push_back( node );
                comps.push_back( comp );
            }
        } else if ( vec != p ) {
            minTimp[node] = min( minTimp[node], timp[vec] );
        }
    }
}
int main() {
    ifstream fin( "biconex.in" );
    ofstream fout( "biconex.out" );
    int n, m;
    fin >> n >> m;
    for ( int i = 1, a, b; i <= m; i ++ ) {
        fin >> a >> b;
        edges[a].push_back( b );
        edges[b].push_back( a );
    }

    dfs( 1 );

    fout << comps.size() << '\n';
    for ( auto comp : comps ) {
        for ( auto node : comp ) fout << node << ' ';
        fout << '\n';
    }
    return 0;
}