#include <cstdio>
#include <vector>
#include <stack>
using namespace std;

const int nmx = 100005;

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

void afish(const int parinte, const int nod){
    aux.clear();
    while(s.top() != nod){
        aux.push_back(s.top());
        s.pop();
    }
    s.pop();
    aux.push_back(nod);
    aux.push_back(parinte);
    r.push_back(aux);
}

void dfs(const int parinte, const int nod){
    niv[nod] = Min[nod] = niv[parinte] + 1;
    for(vector<int>::iterator it = g[nod].begin(); it != g[nod].end(); ++it){
        if(*it == parinte)
            continue;
        if(not niv[*it]){
            s.push(*it);
            dfs(nod,*it);
            Min[nod] = min(Min[nod], Min[*it]);
            if(Min[*it] >= niv[nod]){
                afish(nod,*it);
            }
        }
        else
            Min[nod] = min(Min[nod],niv[*it]);
    }
}

int main() {
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    scanf("%d %d", &n, &m);
    for(; m; --m) {
        int n1, n2;
        scanf("%d %d", &n1, &n2);
        g[n1].push_back(n2);
        g[n2].push_back(n1);
    }
    for(int i = 1; i <= n; ++i)
        if(not niv[i]) {
            s.push(0);
            dfs(0,i);
            s.pop();
        }
    size_t total = r.size();
    printf("%d\n", total);
    for(size_t i = 0; i < total; ++i){
        size_t nr = r[i].size();
        for(size_t j = 0; j < nr; ++j)
            printf("%d ", r[i][j]);
        printf("\n");
    }
    return 0;
}