#include <bits/stdc++.h>
#define NMAX 100010
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,low[NMAX],t[NMAX],i,k,viz[NMAX],x,y;
vector<int>v[NMAX],c[NMAX];
stack<int>s;
void dfs(int node,int parent=0)
{
    s.push(node);
    low[node]=t[node]=t[parent]+1;
    viz[node]=1;
    for(auto it:v[node])
        if(it!=parent)
        {
            if(viz[it])
            {
                low[node]=min(low[node],t[it]);
                continue;
            }
            dfs(it,node);
            low[node]=min(low[node],low[it]);
            if(t[node]<=low[it])
            {
                k++;
                while(s.top()!=it)
                {
                    c[k].push_back(s.top());
                    s.pop();
                }
                c[k].push_back(s.top()); ///it
                s.pop();
                c[k].push_back(node);
            }
        }
}
int main()
{
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(viz[i]==0)
            dfs(i);
    fout<<k<<'\n';
    for(i=1;i<=k;i++)
    {
        for(auto x:c[i])
            fout<<x<<" ";
        fout<<'\n';
    }
    return 0;
}