#include <fstream>
#include <vector>
#include <stack>
using namespace std;
 
ifstream in("biconex.in"); ofstream out("biconex.out");
int n,m,nr=0;
 
vector <int> v[100001], low, lvl, v2[50001];
stack < pair <int,int> > s;
pair <int, int> l;
 
void read()
{
    int a,b;
    in >> n >> m;
    low.resize(n+2);
    lvl.resize(n+2);
    for (int i=1; i<=m; i++)
    {
        in >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (int i=0; i<=n; i++)
        lvl[i]=0;
}
 
int min(int a, int b)
{
    if (a<b)
        return a;
    else
        return b;
}
 
void dfs(int x, int px, int k)
{
    int y;
    lvl[x]=low[x]=k;
    for (int i=0; i<v[x].size(); i++)
    {
        y=v[x][i];
        if(y!=px)
        {
            if (lvl[y])
                low[x]=min(low[x],lvl[y]);
            else           
            {
                s.push(make_pair(x,y));
                dfs(y,x,k+1);
                low[x]=min(low[x],low[y]);
                if (low[y]>=lvl[x])
                {
                    nr++;
                    do
                    {
                        l=s.top();
                        s.pop();
                        v2[nr].push_back(l.second);
                    } while (l!=make_pair(x,y));
                    v2[nr].push_back(l.first);
                }
            }
        }      
    }
}
 
void write()
{
    out << nr << "\n";
    for (int i=1; i<=nr; i++)
    {
        for (int j=0; j<v2[i].size(); j++)
            out << v2[i][j] << " ";
        out << "\n";
    }
}
 
int main ()
{
    read();
    dfs(1,1,1);
    write();
}