#include <cstdio>
#include <vector>
#include <stack>

using namespace std;

const int nmx = 100002;

int n,m,niv[nmx],mi[nmx];
vector <int> g[nmx],r;
stack <int> st;
vector <vector<int> > sol;

void citire(){
    scanf("%d %d", &n, &m);
    int nod1,nod2;
    for(int i = 1; i <= m; ++i){
        scanf("%d %d", &nod1, &nod2);
        g[nod1].push_back(nod2);
        g[nod2].push_back(nod1);
    }
}

void adaugare_sol(int nod, int tata){
    r.clear();
    while(st.top() != nod){
        r.push_back(st.top());
        st.pop();
    }
    st.pop();
    r.push_back(nod);
    r.push_back(tata);
    sol.push_back(r);
}

void dfs(int nod, int tata){
    niv[nod] = mi[nod] = niv[tata] + 1;
    for(vector<int>::iterator it = g[nod].begin(); it != g[nod].end(); ++it){
        if (*it == tata)
            continue;
        if(not niv[*it]){
            st.push(*it);
            dfs(*it,nod);
            mi[nod] = min(mi[nod],mi[*it]);
            if(mi[*it] >= niv[nod])
                adaugare_sol(*it,nod);
        }
        else
            mi[nod] = min(mi[nod],niv[*it]);
    }
}

void afish(){
    printf("%d\n", sol.size());
    for(int i = 0; i < sol.size(); ++i){
        for(int j = 0; j < sol[i].size(); ++j)
            printf("%d ", sol[i][j]);
        printf("\n");
    }
}

int main(){
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);

    citire();

    for(int i = 1; i <= n; ++i){
        st.push(i);
        dfs(i,0);
        st.pop();
    }

    afish();

    return 0;
}