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

using namespace std;

const int nmx = 100002;

int n,m,leval[nmx],ant[nmx];
vector <int> g[nmx],aux;
vector <vector<int> > ras;
stack <int> st;

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 pregatire_afish(int nod, int tata){
    aux.clear();
    while(st.top() != nod){
        aux.push_back(st.top());
        st.pop();
    }
    st.pop();
    aux.push_back(nod);
    aux.push_back(tata);
    ras.push_back(aux);
}

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

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

int main(){
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    citire();
    for(int i = 1; i <= n; ++i)
    if(not leval[i]){
        st.push(i);
        dfs(i,0);
        st.pop();
    }
    afish();
    return 0;
}