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

using namespace std;

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

const int maxn = 100005;

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

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.insert(s);
}

inline void dfs(int node, int father) {
    dflevel[node] = lowlink[node] = dflevel[father] + 1;
    for(auto it : g[node]) {
        if(it == father)
            continue;
        if(!dflevel[it]) {
            st.push(make_pair(node, it));
            dfs(it, node);
            lowlink[node] = min(lowlink[node], lowlink[it]);
            if(lowlink[it] >= dflevel[node])
                extractbcc(node, it);
        }
        else
            lowlink[node] = min(lowlink[node], dflevel[it]);
    }
}

int main() {
    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(auto comp : bcc) {
        for(auto it : comp)
            fout << it << ' ';
        fout << '\n';
    }
}