#include <bits/stdc++.h>

using namespace std;

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

int n,m,i,x,y,niv[100010],up[100010];
vector<int> v[100010];
vector<vector<int> > C;
stack<int> St;
bitset<100010> viz;

void dfs(int poz,int tata){
    viz[poz]=1;
    for(auto it:v[poz])
        if(it!=tata)
            if(!viz[it]){
                niv[it]=up[it]=niv[poz]+1;
                St.push(it);dfs(it,poz);
                up[poz]=min(up[poz],up[it]);
                if(up[it]>=niv[poz]){
                    vector<int> c;
                    while(St.top()!=it){
                        c.push_back(St.top());
                        St.pop();
                    }
                    c.push_back(St.top());
                    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>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(!viz[i])
            dfs(i,0);
    g<<C.size()<<'\n';
    for(auto it:C){
        for(auto that:it)
            g<<that<<' ';
        g<<'\n';
    }
    return 0;
}