#include <bits/stdc++.h>
#define NMAX 100010
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,id[NMAX],low[NMAX],bcc,i,j,x,y,timp,onstack[NMAX];
vector<int>v[NMAX],bc[NMAX];
stack<int>s;
void dfs(int node)
{
    id[node]=low[node]=++timp;
    s.push(node);
    onstack[node]=1;
    for(auto it:v[node])
    {
        if(id[it])
        {
            low[node]=min(low[node],low[it]);
            continue;
        }
        dfs(it);
        low[node]=min(low[node],low[it]);
        if(id[node]<=low[it])
        {
            bcc++;
            while(s.top()!=it)
            {
                bc[bcc].push_back(s.top());
                s.pop();
            }
            bc[bcc].push_back(it);
            s.pop();
            bc[bcc].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(id[i]==0)
            dfs(i);
    fout<<bcc<<'\n';
    for(i=1;i<=bcc;i++)
    {
        for(auto it:bc[i])
            fout<<it<<" ";
        fout<<'\n';
    }
    return 0;
}