#include <bits/stdc++.h>

using namespace std;

const int NMAX = 100000;

bool viz[NMAX + 1];
vector <int> edges[NMAX + 1];
int min_timp[NMAX + 1];
int timp[NMAX + 1], t = 0;
stack <int> st;

void dfs( int node, int p, vector <vector<int>>& comps ) {
    min_timp[node] = timp[node] = ++t;
    viz[node] = true;
    st.push( node );
    for ( auto vec : edges[node] ) {
        if ( !viz[vec] ) {
            dfs( vec, node, comps );
            min_timp[node] = min( min_timp[node], min_timp[vec] );
            if ( min_timp[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 && timp[vec] < min_timp[node] ) {
            min_timp[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 );
    }
    vector <vector<int>> comps;

    for ( int i = 1; i <= n; i ++ ) {
        if ( !viz[i] ) {
            dfs( i, 0, comps );
        }
    }
    fout << comps.size() << '\n';
    for ( auto comp : comps ) {
        for ( auto node : comp ) {
            fout << node << ' ';
        }
        fout << '\n';
    }
    return 0;
}