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

using namespace std;

const char infile[] = "biconex.in";
const char outfile[] = "biconex.out";

ifstream cin(infile);
ofstream cout(outfile);

const int MAXN = 100005;
const int oo = 0x3f3f3f3f;

typedef vector<int> Graph[MAXN];
typedef vector<int> :: iterator It;

const inline int min(const int &a, const int &b) { if( a > b ) return b;   return a; }
const inline int max(const int &a, const int &b) { if( a < b ) return b;   return a; }
const inline void Get_min(int &a, const int b)    { if( a > b ) a = b; }
const inline void Get_max(int &a, const int b)    { if( a < b ) a = b; }

int DFlevel[MAXN], lowLink[MAXN], N, M, S, D;
stack < pair<int, int> > myStack;
vector < set<int> > biconnectedComponents;
Graph G;

inline void extractComponents(const int &Node, const int &Ancestor) {
    set <int> actCon;
    int x, y;
    do {
        x = myStack.top().first;
        y = myStack.top().second;
        myStack.pop();
        actCon.insert(x);
        actCon.insert(y);
    } while(x != Node || y != Ancestor);
    biconnectedComponents.push_back(actCon);
}

void DFs(const int &Node, const int &Father, const int &actLevel) {
    DFlevel[Node] = lowLink[Node] = actLevel;
    //cout << Da << '\n';
    for(It it = G[Node].begin(), fin = G[Node].end(); it != fin ; ++ it) {
        if(*it == Father)
            continue;
        if(!DFlevel[*it]) {
            myStack.push(make_pair(Node, *it));
            DFs(*it, Node, actLevel + 1);
            lowLink[Node] = min(lowLink[Node], lowLink[*it]);
            if(lowLink[*it] >= DFlevel[Node]) {
                extractComponents(Node, *it);
            }
        }
        else lowLink[Node] = min(lowLink[Node], DFlevel[*it]);
    }
}

int main() {
    //cin >> S >> D;
    cin >> N >> M;
    for(int i = 1 ; i <= M ; ++ i) {
        int x, y;
        cin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i = 1 ; i <= N ; ++ i)
        DFs(i, 0, 1);
    cout << biconnectedComponents.size() << '\n';
    for(vector <set <int> > :: iterator it = biconnectedComponents.begin(), fin = biconnectedComponents.end();
        it != fin ; ++ it, cout << '\n')
        for(set<int> :: iterator i = it->begin(), fi = it->end(); i != fi ; ++ i)
            cout << *i << ' ';
    cin.close();
    cout.close();
    return 0;
}