#include <bits/stdc++.h>
#define Nmax 100005
using namespace std;
ifstream fin ("biconex.in");
ofstream fout ("biconex.out");

vector <vector <int>> b;
vector <int> v[Nmax];
stack <int> s;
int niv[Nmax], mi[Nmax], t[Nmax], n, m, x, y;
void dfs(int x)
{
    mi[x]=niv[x];
    s.push(x);
    for(auto it:v[x])
        if(it!=t[x])
        {
            if(niv[it])
                mi[x]=min(mi[x],niv[it]);
            else
            {
                t[it]=x;
                niv[it]=niv[x]+1;
                dfs(it);
                mi[x]=min(mi[x], mi[it]);
            }
        }
    if(mi[x]>=niv[x]-1 && x!=1)
    {
        b.push_back(*new vector <int>);
        while(s.top()!=x)
        {
            b.back().push_back(s.top());
            s.pop();
        }
        b.back().push_back(s.top());
        s.pop();
        b.back().push_back(t[x]);
    }
}
int main()
{
    fin >> n >> m;
    for(int i=1;i<=m;i++)
    {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    niv[1]=1;
    dfs(1);
    fout << b.size() << '\n';
    for(int i=0;i<b.size();i++)
    {
        for(auto it:b[i])
            fout << it << ' ';
        fout << '\n';
    }
    return 0;
}