#include <bits/stdc++.h>

using namespace std;

ifstream f("biconex.in");
ofstream g("biconex.out");

int n,m,i,a,b,k,up[100010],niv[100010];
vector<int> c,v[100010];
vector<vector<int> > C;
bitset<100010> viz;
stack<int> St;

void dfs(int poz)
{
    viz[poz]=1;
    for(auto it:v[poz])
        if(!viz[it])
        {
            St.push(it);
            niv[it]=++k;
            up[it]=niv[it];
            dfs(it);
            if(up[it]==niv[poz])
            {
                c.resize(0);
                while(St.top()!=it)
                {
                    c.push_back(St.top());
                    St.pop();
                }
                c.push_back(it);St.pop();
                c.push_back(poz);
                C.push_back(c);
            }
        }
        else
            up[poz]=min(up[poz],niv[it]);
}

int main()
{
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for(i=1;i<=n;i++)
        if(!viz[i])
        {
            niv[i]=++k;
            up[i]=niv[i];
            dfs(i);
        }
    g<<C.size()<<'\n';
    for(auto it:C)
    {
        for(auto that:it)
            g<<that<<' ';
        g<<'\n';
    }
    return 0;
}