#include <fstream>
#include <vector>
#include <stack>
#include <bitset>

using namespace std;

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

// nma = nivel minim accesibil
int n, m, x, y, niv[100005], nma[100005], cB;
vector<int> G[100005], ans[100005];
bitset<100005> v;
stack<int> st;

void compBiconexe(int nod, int i) {
    if(niv[nod] <= nma[i]) {
        cB++;
        do {
            x = st.top();
            st.pop();
            ans[cB].push_back(x);
            
        } while(x != i);
        ans[cB].push_back(nod);
    }
}

void dfs(int nod, int tata) {
    v[nod] = true;
    niv[nod] = niv[tata] + 1;
    nma[nod] = niv[nod];
    /// stiva pt componentele biconexe
    st.push(nod);
    int desc = 0;
    for(auto i : G[nod]) {
        if(i != tata) {
            if(v[i]) {
                nma[nod] = min(nma[nod], niv[i]);
            } else {
                desc++;
                dfs(i, nod);
                nma[nod] = min(nma[nod], nma[i]);
                compBiconexe(nod, i);
            }
        }
    }
}

int main() {
    fin >> n >> m;
    for(int i = 1; i <= m; i++) {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    fin.close();
    for(int i = 1; i <= n; i++) {
        if(!v[i]) {
            dfs(i, 0);
        }
    }
    fout << cB << "\n";
    for(int i = 1; i <= cB; i++) {
        for(int it : ans[i]) {
            fout << it << " ";
        }
        fout << "\n";
    }
    return 0;
}