#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
typedef pair<int,int> pii;
int n,m,parent,niv[200005],nivmin[200005];
vector<int> muchii[200005];
vector<vector<int>> sol;
vector<pii> st;
bool use[200005];
void getans(int x,int y)
{
    vector<int> v;
    while(true)
    {
        int a=st.back().first;
        int b=st.back().second;
        v.push_back(a);
        v.push_back(b);
        st.pop_back();
        if((a==x&&b==y)||(a==y&&b==x))
            break;
    }
    sol.push_back(v);
}
void dfs(int nod,int parent)
{
    use[nod]=1;
    for(auto i:muchii[nod])
    {
        if(i==parent)
            continue;
        if(!use[i])
        {
            st.push_back({nod,i});
            niv[i]=niv[nod]+1;
            nivmin[i]=niv[i];
            dfs(i,nod);
            nivmin[nod]=min(nivmin[nod],nivmin[i]);
            if(nivmin[i]>=niv[nod])
                getans(nod,i);
        }
        else
        {
            nivmin[nod]=min(nivmin[nod],niv[i]);
            /*if(nivmin[i]>=niv[nod])
                getans(nod,i);*/
        }
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    fin.tie(0);
    fout.tie(0);
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        fin>>a>>b;
        muchii[a].push_back(b);
        muchii[b].push_back(a);
    }
    dfs(1,0);
    fout<<sol.size()<<'\n';
    for(auto i:sol)
    {
        sort(i.begin(),i.end());
        i.erase(unique(i.begin(),i.end()),i.end());
        for(auto j:i)
            fout<<j<<" ";
        fout<<'\n';
    }
    return 0;
}