#include <bits/stdc++.h>

#define int_pair std::pair <int, int>

#define MAXN 100005

int N, M, BCXSize;
std::vector <int> ADC[MAXN];
std::vector <int> BCX[MAXN];

inline void AddEdge(int X, int Y) {
    ADC[X].push_back(Y);
    ADC[Y].push_back(X);
}

int Time, Discovery[MAXN], Lowlink[MAXN];
std::stack <int_pair> S;
void DFS(int Vertex = 1) {
    Discovery[Vertex] = Lowlink[Vertex] = ++Time;

    for (auto Edge:ADC[Vertex]) {
        if (Discovery[Edge])
            Lowlink[Vertex] = std::min(Lowlink[Vertex], Discovery[Edge]);
        else {
            S.push({Vertex, Edge});
            DFS(Edge);

            Lowlink[Vertex] = std::min(Lowlink[Vertex], Lowlink[Edge]);
            if (Discovery[Vertex] <= Lowlink[Edge]) {
                ++ BCXSize;
                while (S.top().first != Vertex)
                    BCX[BCXSize].push_back(S.top().second),
                    S.pop();

                BCX[BCXSize].push_back(S.top().second);
                BCX[BCXSize].push_back(Vertex);
                S.pop();

                std::sort(BCX[BCXSize].begin(), BCX[BCXSize].end());
            }
        }
    }
}

std::ifstream In ("biconex.in");
std::ofstream Out("biconex.out");

void Citire() {
    In >> N >> M;
    for (int i=1, X, Y; i<=M; ++i)
        In >> X >> Y, AddEdge(X, Y);
}

void Rezolvare() {
    for (int i=1; i<=N; ++i)
        if (!Discovery[i])
            DFS(i);

    Out << BCXSize << '\n';
    for (int i=1; i<=BCXSize; ++i, Out << '\n')
        for (auto Node:BCX[i])
            Out << Node << ' ';
}

int main()
{
    Citire();
    Rezolvare();

    return 0;
}