#include <bits/stdc++.h>
#define SIZE 100005
using namespace std;

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

int n,m,k,vf,niv[SIZE],st[SIZE],up[SIZE];
// up[x] reprezinta cel mai de sus nod la care se poate ajunge din x
vector<int>a[SIZE],sol[SIZE];

void dfs_tree(int x)
{
    st[++vf]=x;
    up[x]=niv[x];
    for(auto u:a[x])
        if(niv[u]!=0)up[x]=min(up[x],niv[u]);
        else
        {
            niv[u]=niv[x]+1;
            dfs_tree(u);
            up[x]=min(up[x],up[u]);
            if(up[u]>=niv[x])
            {
                k++;
                while(st[vf]!=u)
                    sol[k].push_back(st[vf--]);
                sol[k].push_back(st[vf--]);
                sol[k].push_back(x);
            }
        }
}

int main()
{
    int i,x,y;
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(niv[i]==0)
    {
        niv[i]=1;
        dfs_tree(i);
    }
    g<<k<<'\n';
    for(i=1;i<=k;i++)
    {
        for(auto u:sol[i])g<<u<<' ';
        g<<'\n';
    }
}