#include <cstdio>
#include <vector>
#include <stack>
#define pb push_back
using namespace std;

const int nmx = 100005;

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

void afish(const int nod, const int tata){
    aux.clear();
    while(st.top() != nod){
        aux.pb(st.top());
        st.pop();
    }
    st.pop();
    aux.pb(nod);
    aux.pb(tata);
    r.pb(aux);
}

void parcurgere(const int nod, const int tata){
    minim[nod] = niv[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);
            parcurgere(*it,nod);
            minim[nod] = min(minim[*it],minim[nod]);
            if(minim[*it] >= niv[nod])
                afish(*it,nod);
        }
        else
            minim[nod] = min(minim[nod],niv[*it]);
    }
}

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

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

    for(int i = 1; i <= n; ++i)
    if(not niv[i]){
        st.push(i);
        parcurgere(i,0);
        st.pop();
    }

    printf("%d\n", r.size());
    for(size_t i = 0; i < r.size(); ++i){
        for(size_t j = 0; j < r[i].size(); ++j)
            printf("%d ", r[i][j]);
        printf("\n");
    }

    return 0;
}