#include <bits/stdc++.h>
using namespace std;
int n,m,i,j,x,y,nr,k,st[200010],low[100010],niv[100010];
vector<int>v[100010],ans[100010];
bool ap[100010];
void dsf/*da...e intentionat...*/(int nod,int tata)
{
    ap[nod]=true;
    niv[nod]=niv[tata]+1;
    low[nod]=niv[nod];

    for(int i=0; i<v[nod].size(); ++i)
        if(ap[v[nod][i]]&&v[nod][i]!=tata)low[nod]=min(low[nod],niv[v[nod][i]]);
        else if(!ap[v[nod][i]])
        {
            st[++k]=v[nod][i];
            dsf(v[nod][i],nod);
            low[nod]=min(low[nod],low[v[nod][i]]);
            if (low[v[nod][i]]>=niv[nod])
            {
                ++nr;
                while(st[k]!=v[nod][i])ans[nr].push_back(st[k--]);
                --k;
                ans[nr].push_back(nod);
                ans[nr].push_back(v[nod][i]);
            }
        }
}
int main()
{
    ifstream f ("biconex.in");
    ofstream g ("biconex.out");
    f>>n>>m;
    for(i=1; i<=m; ++i)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    st[++k]=1;
    dsf(1,0);
    g<<nr<<'\n';
    for(i=1; i<=nr; ++i)
    {
        for(j=0; j<ans[i].size(); ++j)
            g<<ans[i][j]<<" ";
        g<<'\n';
    }
    return 0;
}