#include <fstream>
#include <vector>
#include <stack>
#include <bitset>
#include <set>

#define DIM 100010

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");


vector<int> L[DIM];
bitset<DIM> V;
stack<pair<int, int> > S;
set<int> R[DIM];
set<int>::iterator it;
int Low[DIM];

pair<int, int> p;
int n, m, i, j, x, y, cbc;

void dfs(int nod, int niv, int tata) {
    V[nod] = 1;
    Low[nod] = niv;

    for (int i=0;i<L[nod].size(); i++) {


        int fiu = L[nod][i];
        if (fiu == tata)
            continue;

        if (V[fiu] == 0) {
            S.push(make_pair(nod, fiu));
            dfs(fiu, niv+1, nod);
            Low[nod] = min(Low[nod], Low[fiu]);

            // tocmai m-am intors din fiul x al lui nod
            if (Low[fiu] >= niv) {
                // am componenta biconexa provocata de muchia nod,x
                // scot din stiva tot ce am pus dupa muchia nod,x inclusiv
                cbc ++;
                do {
                    p = S.top();
                    S.pop();
                    R[cbc].insert(p.first);
                    R[cbc].insert(p.second);
                } while (nod != p.first || fiu!=p.second);
            }

        } else
            Low[nod] = min(Low[nod], Low[fiu]);
    }
}


int main () {
    fin>>n>>m;
    for (i=1;i<=m;i++) {
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }

    for (i=1;i<=n;i++) {
        if (!V[i])
            dfs(i, 1, 0);
    }

    fout<<cbc<<"\n";
    for (i=1;i<=cbc;i++) {
        for (it = R[i].begin(); it!=R[i].end(); it++) {
            fout<<*it<<" ";
        }
        fout<<"\n";
    }
    return 0;
}