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

#define Nmax 100005

using namespace std;

int low[Nmax], nivel[Nmax], n, m;
stack<int> S;
vector<int> sol[Nmax];
vector<int> L[Nmax];
int nr;

void citire()
{
    scanf("%d %d",&n, &m);
    for (int i=1; i<=m; i++)
    {
        int x,y;
        scanf("%d %d",&x, &y);
        L[y].push_back(x);
        L[x].push_back(y);
    }
}

void adaugaComponentaBiconexa(int nod, int vecin)
{
    ++nr;
    while(S.top() != vecin)
    {
        sol[nr].push_back(S.top());
        S.pop();
    }
    sol[nr].push_back(nod);
    sol[nr].push_back(vecin);
    S.pop();
}

void df(int nod, int tata)
{
    nivel[nod] = nivel[tata] + 1;
    low[nod] = nivel[nod];
    for (int i=0; i<L[nod].size(); i++)
    {
        int vecin = L[nod][i];
        if (vecin == tata)
            continue;
        if (!nivel[vecin])
        {
            S.push(vecin);
            df(vecin, nod);
            low[nod] = min(low[nod], low[vecin]);
            if (low[vecin] >= nivel[nod])
                adaugaComponentaBiconexa(nod, vecin);
        }
        else
            low[nod] = min(low[nod], nivel[vecin]);

    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    citire();
    for(int i=1; i<=n; i++)
        if (!nivel[i])
        {
            S.push(i);
            df(i, 0);
            S.pop();
        }

    printf("%d\n",nr);
    for (int i=1; i<=nr; i++)
    {
        for (int j=0; j<sol[i].size(); j++)
            printf("%d ",sol[i][j]);
        printf("\n");
    }

    return 0;
}