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

const int NMAX = 100010;

int N, M, A, B, Level[NMAX], Low[NMAX];
vector<int> G[NMAX];
vector<vector<int> > BC;
stack<pair<int, int> > S;

void GetBC(int X, int Y)
{
    vector<int> CrtBC;
    pair<int, int> Now;
    do
    {
        Now = S.top();
        S.pop();
        CrtBC.push_back(Now.second);
    }while(Now.first != X && Now.second != Y);
    CrtBC.push_back(Now.first);
    BC.push_back(CrtBC);
}

void DFS(int Node, int Father = 0)
{
    Low[Node] = Level[Node];
    for(int i = 0; i < G[Node].size(); ++ i)
    {
        int Vec = G[Node][i];
        if(Vec == Father) continue;

        if(!Level[Vec])
        {
            Level[Vec] = Level[Node] + 1;
            S.push(make_pair(Node, Vec));
            DFS(Vec, Node);
            Low[Node] = min(Low[Node], Low[Vec]);
            if(Level[Node] <= Low[Vec])
                GetBC(Node, Vec);
        }else Low[Node] = min(Low[Node], Level[Vec]);
    }
}

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

    scanf("%i %i", &N, &M);
    for(int i = 1; i <= M; ++ i)
    {
        scanf("%i %i", &A, &B);
        G[A].push_back(B);
        G[B].push_back(A);
    }

    for(int i = 1; i <= N; ++ i) if(!Level[i]) Level[i] = 1, DFS(i);

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