#include <fstream>
#include <iostream>
#include <set>
#include <stack>
#include <vector>
#include <algorithm>
 
using namespace std;
 
#define MAXN  100001
 
int M,N;

vector<int> L[MAXN]; 
int LEVEL[MAXN+1];
int LOWER[MAXN+1];
 
vector <vector <int> > C;
 
stack<int> S;
  
void cache_bc(int node){
    vector <int> con; 
	int elem;
    do {
        elem = S.top();
        S.pop();
        con.push_back(elem);		
    }
    while(elem!=node);
    C.push_back(con);
}
 
void depth(int node, int prev, int level){
    vector <int>::iterator it;
 
    LEVEL[node]=level;
	LOWER[node]=level;

    for (it = L[node].begin(); it != L[node].end(); it++) {
        if (*it == prev)   
			continue ;
        if (LEVEL[*it] == -1) { // nod nevizitat
            S.push(*it);
            depth(*it, node, level + 1);
			if(LOWER[node] > LOWER[*it])
				LOWER[node] = LOWER[*it];
			if(LOWER[*it] >= LEVEL[node]){
                cache_bc(node);
				S.push(node);
			}
        }
		else{ // nod parinte
            if(LOWER[node] > LEVEL[*it])
				LOWER[node] = LEVEL[*it];
		}
    }
}

int main(void){
	freopen("biconex.in","r",stdin);
	freopen("biconex.out","w",stdout);

	scanf("%d %d",&N,&M);

	int x,y;
	for(int i=0;i<M;i++){
		scanf("%d %d",&x,&y);
		L[x].push_back(y);
		L[y].push_back(x);
	}

	for(int i=1;i<=N;i++)
		LEVEL[i]=-1;

	S.push(1);
	depth(1, 0, 0);

	printf("%d\n",C.size());
    for (int i = 0; i < C.size(); i++) {
        for (int j = 0; j < C[i].size(); j++)
            printf("%d ",C[i][j]);
		printf("\n");
    }

    return 0;
}