#include <bits/stdc++.h>
#define MAX 100100
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
vector<int>g[MAX];
vector<int>nrc[MAX];
stack<int>s;
int nivel[MAX],nma[MAX];
bool uz[MAX];
void dfs(int node,int tata);
int n,m,nr;
void rd();
int main()
{
    int i,j;
    rd();
    dfs(1,0);
    fout<<nr<<endl;
    for(i=1; i<=n; i++)
    {
        for(j=0; j<nrc[i].size(); j++)
            fout<<nrc[i][j]<<' ';
        fout<<endl;
    }
    return 0;
}
void rd()
{
    int i,x,y;
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
}
void dfs(int node,int tata)
{
    int i;
    nivel[node]=nivel[tata]+1;
    nma[node]=nivel[node];
    uz[node]=1;
    s.push(node);
    for(i=0; i<g[node].size(); i++)
        if(g[node][i]!=tata)
        {
            if(uz[g[node][i]])
            {
                if(nivel[g[node][i]]<nma[node])
                    nma[node]=nivel[g[node][i]];
            }
            else
            {
                dfs(g[node][i],node);
                if(nma[g[node][i]]<nma[node])
                    nma[node]=nma[g[node][i]];
                if(nma[g[node][i]]>=nivel[node])
                {
                    nr++;
                    while(s.top()!=g[node][i])
                    {
                        nrc[nr].push_back(s.top());
                        s.pop();
                    }
                    s.pop();
                    nrc[nr].push_back(node);
                    nrc[nr].push_back(g[node][i]);
                }
            }
        }
}