#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")
#include <bits/stdc++.h>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

const int N = 1e5 + 5;
int n, m, lvl[N], low[N];
vector<int> v[N];
bool viz[N];
stack<pair<int, int>> s;
vector<set<int>> componente;

void DFS1(int nod, int niv)
{
    viz[nod] = 1;
    lvl[nod] = niv;
    low[nod] = niv;
    for (int i : v[nod])
        if (!viz[i])
        {
            s.push({i, nod});
//                cout << i << ' ' << nod << '\n';
            DFS1(i, niv + 1);
            low[nod] = min(low[nod], low[i]);
            if (low[i] >= lvl[nod])
            {
                int a, b;
                set<int> comp;
                do
                {
                    a = s.top().first;
                    b = s.top().second;
                    comp.insert(a);
                    comp.insert(b);
//                    cout << a << ' ' << b << '\n';
                    s.pop();
                } while (a != i || b != nod);
//                cout << 'a';
                componente.push_back(comp);
            }
        }
        else
        {
            low[nod] = min(low[nod], lvl[i]);
        }
}

int main()
{
    fin >> n >> m;
    while (m--)
    {
        int a, b;
        fin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (int i = 1; i <= n; i++)
        low[i] = 1e9;
    DFS1(1, 0);
    fout << componente.size() << '\n';
    for (set<int> &s : componente)
    {
        for (int i : s)
            fout << i << ' ';
        fout << '\n';
    }
}