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

#define DIM 1666013
#define Nmax 100005
#define next (++pointer == DIM) ? fread(buffer,1,DIM,stdin),pointer = 0 : 0

using namespace std;
char buffer[DIM];
int pointer = DIM - 1;

void scanf(int &A)
{
    A = 0;
    for(;'0'>buffer[pointer]||buffer[pointer]>'9';next);
    for(;'0'<=buffer[pointer]&&buffer[pointer]<='9';next)
        A = A * 10 + buffer[pointer] - 48;
}

int N,M,nb;
vector<int> G[Nmax];
vector<int> bcn[Nmax];
bitset<Nmax> used;
stack<int> S;
int nivel[Nmax];
int low[Nmax];

void afish(int k,int v)
{
    ++nb;
    while(!S.empty() && S.top() != v)
    {
        bcn[nb].push_back(S.top());
        S.pop();
    }
    bcn[nb].push_back(v);
    bcn[nb].push_back(k);
    S.pop();
}

void DFS(int k,int dad)
{
    used[k] = 1;
    nivel[k] = nivel[dad] + 1;
    low[k] = nivel[k];
    for(vector<int>::iterator it = G[k].begin(); it != G[k].end(); ++it)
        if(!used[*it])
        {
            S.push(*it);
            DFS(*it,k);
            low[k] = min(low[k],low[*it]);
            if(nivel[k] <= low[*it])
                afish(k,*it);
        }
        else
            if(*it != dad && nivel[*it] < low[k])
                low[k] = nivel[*it];
}

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

    scanf(N),scanf(M);
    for(int i = 1; i <= M; ++i){
        int a,b;
        scanf(a),scanf(b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
    for(int i = 1; i <= N; ++i)
        if(!used[i])
        {
            S.push(i);
            DFS(i,0);
            S.pop();
        }
    printf("%d\n",nb);
    for(int i = 1; i <= nb; ++i)
    {
        for(vector<int>::reverse_iterator it = bcn[i].rbegin(); it != bcn[i].rend(); ++it)
            printf("%d ",*it);
        printf("\n");
    }

    return 0;
}