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

#define Nmax 100050
#define DIM 1000005

using namespace std;
int N,M,nrb;
bitset<Nmax>used;
vector<int> G[Nmax],bix[Nmax];
stack<int> S;
int nivel[Nmax];
int low[Nmax];

char buff[DIM];
int pz = DIM-1;
void scan(int &A)
{
    A = 0;
    while('0'> buff[pz] || buff[pz] > '9')
        if(++pz == DIM) fread(buff,1,DIM,stdin),pz = 0;
    while('0' <= buff[pz] && buff[pz] <= '9')
    {
        A = A * 10 + buff[pz] - 48;
        if(++pz == DIM)
            fread(buff,1,DIM,stdin),pz = 0;
    }
}

void read()
{
    scan(N);scan(M);
    int a,b;
    for(int i = 1; i <= M; ++i)
    {
        scan(a),scan(b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
}

void afish(int k,int v)
{
    ++nrb;
    while(S.top()!= v)
    {
        bix[nrb].push_back(S.top());
        S.pop();
    }
    bix[nrb].push_back(k);
    bix[nrb].push_back(v);
    S.pop();
}

void DFS(int k,int tata)
{
    used[k] = 1;
    nivel[k] = nivel[tata] + 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 /// muchie de intoarcere
            if(*it != tata && nivel[*it] < low[k])
                low[k] = nivel[*it];
}

void print()
{
    printf("%d\n",nrb);
    for(int i = 1; i <= nrb; ++i)
    {
        for(vector<int>::iterator it = bix[i].begin(); it != bix[i].end(); ++it)
            printf("%d ",*it);
        printf("\n");
    }
}

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

    read();
    for(int i = 1; i <= N; ++i)
        if(!used[i])
        {
            S.push(i);
            DFS(i,0);
            S.pop();
        }
    print();

    return 0;
}