#include <fstream>
#include <vector>
#include <bitset>
#include <queue>
#include <algorithm>
#include <utility>
#include <string.h>
#include <set>
#include <stack>
#define add push_back
using namespace std;

ifstream cin("biconex.in");
ofstream cout("biconex.out");


const int MAXN = 100005;
const int oo = (1<<31)-1;

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

Graph G;
int N, M;
vector<int> LowLink(MAXN); ///Cel mai mic nivel care poate fi atins de descendentii sai printr-o singura muchi de intoarcere
vector<int> DfLevel(MAXN); ///Nivelul in parcurgerea Df;
vector< set<int> >BiconnectedComponent;
stack< pair<int,int> > Stack;

inline void Get_Min(int &a, int b){
    if(a>b)
        a=b;
}

void ExtractComponents(int X, int Y){
    set<int> Comp;
    int Tx, Ty;
    do{
        Tx = Stack.top().first;
        Ty = Stack.top().second;
        Stack.pop();
        Comp.insert(Tx);
        Comp.insert(Ty);
    }while( Tx != X || Ty != Y);
    BiconnectedComponent.push_back(Comp);
}

void ReadData(){
    cin >> N >> M;
    for(int i = 1 ; i <= M ; ++ i){
        int X, Y;
        cin >> X >> Y;
        G[X].add(Y);
        G[Y].add(X);
    }
}

void DFs(int Node, int Father, int ActLevel){
    DfLevel[Node] = LowLink[Node] = ActLevel;
    for(It it = G[Node].begin(), fin = G[Node].end(); it != fin ; ++ it)
        if(!DfLevel[*it]){
            Stack.push(make_pair(Node, *it)); /// Adaug muchia in Stiva
            DFs(*it, Node, ActLevel + 1);
            Get_Min(LowLink[Node], LowLink[*it]);
            if(LowLink[*it] >= DfLevel[Node])
                ExtractComponents(Node, *it);
        }
        else Get_Min(LowLink[Node], DfLevel[*it]);
}

void WriteData(){
    cout << BiconnectedComponent.size() << "\n";
    for(vector<set<int> > :: iterator it = BiconnectedComponent.begin() , fin = BiconnectedComponent.end() ; it != fin ; ++ it, cout << "\n")
        for(set<int> :: iterator i = it->begin() , j = it->end() ; i != j ; ++ i)
            cout << *i << " ";
}

int main(){
    ReadData();
    DFs(1, 0, 1);
    WriteData();
    cin.close();
    cout.close();
    return 0;
}