#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n, m, k, niv[100005], low[100005], nr_fii;
int st[100005], top;
bool viz[100005];
vector<int> G[100005];
vector<int> componente[200005];
void Biconexitate(int x, int tata)
{
    int i;
    viz[x] = 1;
    niv[x] = low[x] = niv[tata] + 1;
    st[++top] = x;
    for(int e : G[x])
        if(e != tata)
        {
            if(viz[e] == 1)
                low[x] = min(low[x], niv[e]);
            else{
                Biconexitate(e, x);
                low[x] = min(low[x], low[e]);
                if(x == 1) nr_fii++;
                if(niv[x] <= low[e])
                {
                    k++;
                    do{
                        i = st[top--];
                        componente[k].push_back(i);
                    }while(i != e);
                    componente[k].push_back(x);
                }
            }
        }
}

int main()
{
    int i, j;
    fin >> n >> m;
    while(m)
    {
        fin >> i >> j;
        G[i].push_back(j);
        G[j].push_back(i);
        m--;
    }
    Biconexitate(1, 0);
    fout << k << "\n";
    while(k)
    {
        for(int e : componente[k])
            fout << e << " ";
        fout << "\n";
        k--;
    }
    fout.close();
    return 0;
}