#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <set>

using namespace std;

const int maxn = 100005;

int n, m, level[maxn], lowlink[maxn];
vector <int> g[maxn];
stack <pair<int, int> > st;
vector < set<int> > bcc;

inline void extractbcc(int x, int y) {
    int tx, ty;
    set <int> s;
    do {
        tx = st.top().first;
        ty = st.top().second;
        st.pop();
        s.insert(tx);
        s.insert(ty);
    } while(x != tx || y != ty);
    bcc.push_back(s);
}

inline void dfs(int node, int father) {
    level[node] = lowlink[node] = level[father] + 1;
    for(vector <int> :: iterator it = g[node].begin() ; it != g[node].end() ; ++ it) {
        if(*it == father)
            continue;
        if(!level[*it]) {
            st.push(make_pair(node, *it));
            dfs(*it, node);
            lowlink[node] = min(lowlink[node], lowlink[*it]);
            if(lowlink[*it] >= level[node])
                extractbcc(node, *it);
        }
        else
            lowlink[node] = min(lowlink[node], level[*it]);
    }
}

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

    fin >> n >> m;
    for(int i = 1 ; i <= m ; ++ i) {
        int x, y;
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1, 0);
    fout << bcc.size() << '\n';
    for(vector <set<int> > :: iterator it = bcc.begin() ; it != bcc.end() ;  ++ it, fout << '\n')
        for(set<int> :: iterator i = it->begin() ; i != it->end() ; ++ i)
            fout << *i << ' ';
}