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

#define x first
#define y second
#define NMAX 100007
#define FORIT(it, v) for(vector < pair < int, int > >::iterator it = (v).begin(); it != (v).end(); ++it)

using namespace std;

int Viz[NMAX], Critic[NMAX], Level[NMAX];
vector < pair < int, int > > Sol;
vector < vector < int > > Ans;
vector < int > v[NMAX];
stack < pair < int, int > > Edge;
int x, n, m;

vector < int > uni(vector < pair < int, int > > v) {
    vector < int > Val;
    for(int i = 0; i < v.size(); ++i){
        Val.push_back(v[i].x);
        Val.push_back(v[i].y);
    }
    sort(Val.begin(), Val.end());
    Val.resize(unique(Val.begin(), Val.end()) - Val.begin());
    return Val;
}

void dfs(int Nod){
    Viz[Nod] = 1;
    Critic[Nod] = Level[Nod];
    for(int i = 0, Fiu = v[Nod][0]; i < v[Nod].size(); ++i, Fiu = v[Nod][i])
        if(Viz[Fiu] == 0){
            Level[Fiu] = Level[Nod] + 1;
            Edge.push(make_pair(Nod, Fiu));
            dfs(Fiu);
            Critic[Nod] = min(Critic[Nod], Critic[Fiu]);
            if(Critic[Fiu] >= Level[Nod]){
                vector < pair < int, int > > Sol;
                while(Edge.top() != make_pair(Nod, Fiu)){
                    Sol.push_back(Edge.top());
                    Edge.pop();
                }
                Sol.push_back(Edge.top());
                Edge.pop();
                Ans.push_back(uni(Sol));
            }
        }
        else
            if(Level[Fiu] < Level[Nod] - 1)
                Critic[Nod] = min(Critic[Nod], Level[Fiu]);
}

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 A, B;
        scanf("%d %d", &A, &B);
        v[A].push_back(B);
        v[B].push_back(A);
    }
    dfs(1);
    printf("%d\n", Ans.size());
    for(int i = 0; i < Ans.size(); ++i){
        for(int j = 0; j < Ans[i].size(); ++j)
            printf("%d ", Ans[i][j]);
        printf("\n");
    }
    return 0;
}