#include <bits/stdc++.h>

using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n, m, i, j, x, y, niv[100002], mi[100002];
vector<int> gr[100002];
bool fr[100002];

stack<int> st;

vector<vector<int>> rasp;

static inline void Dfs(int nod, int tata = 0) {
    fr[nod] = true;

    st.push(nod);

    niv[nod] = mi[nod] = niv[tata] + 1;
    for(int urm : gr[nod]) {
        if(urm != tata) {
            if(fr[urm]) mi[nod] = min(mi[nod], niv[urm]);
            else {
                Dfs(urm, nod);

                mi[nod] = min(mi[nod], mi[urm]);

                if(niv[nod] <= mi[urm]) {
                    rasp.push_back({});

                    while(st.top() != urm) {
                        rasp.back().push_back(st.top());
                        st.pop();
                    }
                    st.pop();
                    rasp.back().push_back(urm);
                    rasp.back().push_back(nod);
                }
            }
        }
    }
}

int main() {
    fin >> n >> m;
    for(i = 1; i <= m; i++) {
        fin >> x >> y;
        gr[x].push_back(y);
        gr[y].push_back(x);
    }

    for(i = 1; i <= n; i++) {
        if(!fr[i]) Dfs(i);
    }

    fout << rasp.size() << "\n";
    for(vector<int>& vCur : rasp) {
        for(int cur : vCur) fout << cur << " ";
        fout << "\n";
    }

    return 0;
}