#include<stdio.h>
#include<vector>
#include<stack>
#include<algorithm>
using namespace std;
FILE *f,*g;
const int N=100001;
vector< pair<int, int> > muchii;
vector<int> veci[N],varfuri,unic;
vector< vector<int> > comp;
stack< pair<int, int> > alledge;
int depth[100001],updepth[100001],n,m,nr;
bool seen[100001];

void makecomp(void){
    nr++;
    varfuri.clear();
    unic.clear();
    vector< pair<int,int > >::iterator edge;
    edge=muchii.begin();
    while(edge!=muchii.end()){
        varfuri.push_back(edge->first);
        varfuri.push_back(edge->second);
        edge++;
    }
    sort(varfuri.begin(),varfuri.end());
    comp.push_back(varfuri);
    
    vector<int>::iterator varf;
    varf=varfuri.begin();
    int curr=*varf;
    unic.push_back(curr);
    while(varf!=varfuri.end()){
        if (*varf!=curr){
            curr=*varf;
            unic.push_back(curr);
         }
        varf++;
    }
    comp.push_back(unic);
}


void dfs(int n){
    updepth[n]=depth[n];
    seen[n]=1;
    vector<int>::iterator it=veci[n].begin();
    while(it!=veci[n].end()){
        if (!seen[*it]){
           alledge.push(make_pair(n,*it));
           depth[*it]=depth[n]+1;
           printf("good%d",n);
           dfs(*it);
           updepth[n]=min(updepth[n],updepth[*it]);
           if (updepth[*it]>=depth[n]){
               muchii.clear();
               while (alledge.top()!=make_pair(n,*it)) {
                   muchii.push_back(alledge.top());
                   alledge.pop();
               }
               muchii.push_back(alledge.top());
               alledge.pop();
               makecomp(); 
              }
           }
        else if (depth[*it]<updepth[n]) updepth[n]=depth[*it];
        printf("good%d",n);
        it++;
        }
    }


void read(void){
    f=fopen("biconex.in","r");
    g=fopen("biconex.out","w");
    fscanf(f,"%d%d",&n,&m);
    int i,a,b;
    for(i=1;i<=m;i++){
        fscanf(f,"%d%d",&a,&b);
        veci[a].push_back(b);
        veci[b].push_back(a);
    }
}

int main(void){
read();
dfs(1);
vector< vector< int > >::iterator it;
vector<int>::iterator ti;
it=comp.begin();
while(it!=comp.end()){
    ti=(*it).begin();
    while(ti!=(*it).end()) {
        fprintf(g,"%d ",*ti);
        ti++;
    }
    fprintf(g,"\n");
    it++;
}
return 0;
}