#include <bits/stdc++.h>
#define Nmax 100005
using namespace std;
ifstream fin ("biconex.in");
ofstream fout ("biconex.out");

struct muchie
{
    int a, b;
};
stack <muchie> s;
vector <int> v[Nmax];
vector < vector <int> > c;
int l[Nmax], niv[Nmax], t[Nmax], i, j, n, m, nr, x, y;
void dfs(int x, int tata)
{
    int i;
    l[x]=niv[x];
    for(i=0; i<v[x].size(); i++)
    {
        if(niv[x]>niv[v[x][i]]&&v[x][i]!=tata)
            s.push({x, v[x][i]});

        if(niv[v[x][i]]==0)
        {
            niv[v[x][i]]=niv[x]+1;
            dfs(v[x][i], x);

            if(l[x]>l[v[x][i]])
                l[x]=l[v[x][i]];

            if(l[v[x][i]]>=niv[x])
            {
                nr++;
                vector <int> aux;
                muchie u;
                while(1)
                {
                    u=s.top();
                    s.pop();
                    aux.push_back(u.a);
                    aux.push_back(u.b);
                    if((u.a==x&&u.b==v[x][i])||(u.a==v[x][i]&&u.b==x))
                        break;
                }
                c.push_back(aux);
            }

        }
        else if(v[x][i]!=tata&&niv[v[x][i]]<l[x])
            l[x]=niv[v[x][i]];
    }
}
int main()
{
    fin >> n >> m;
    for(i=1; i<=m; i++)
    {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    niv[1]=1;
    dfs(1, 0);
    fout << nr << '\n';
    for(i=0;i<nr;i++)
    {
        sort(c[i].begin(), c[i].end());
        c[i].erase(unique(c[i].begin(), c[i].end()), c[i].end());
        for(j=0;j<c[i].size();j++)
            fout << c[i][j] << ' ';
        fout << '\n';
    }
    return 0;
}