#include<bits/stdc++.h>
using namespace std;
/*for ordered_set
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<pair<int,int>, null_type,less<pair<int,int>>, rb_tree_tag,tree_order_statistics_node_update>
*/
const long long INFll = (long long) 1e18 + 10;
const int INFii = (int) 1e9 + 10;
typedef long long ll;
typedef int ii;
typedef long double dbl;
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
#define maxn 550000
ii n, m, blk[maxn], lt[maxn];
vector<pair<ii,ii>> g[maxn], vlr;
vector<ii> vec, mark, nx;
void dfs(ii u) {
vec.pb(u);
while(g[u].size()) {
ii v = g[u].back().fr;
ii id = g[u].back().sc;
g[u].pop_back();
if(blk[id]) continue;
blk[id] = 1;
dfs(v);
break;
}
}
void solve() {
cin >> n >> m;
for(ii i = 1; i <= m; i++) {
ii u, v; cin >> u >> v;
g[u].pb(mp(v,i));
g[v].pb(mp(u,i));
}
for(ii j = 1; j <= n; j++) {
vec.clear();
mark.clear();
vlr.clear();
nx.clear();
dfs(j);
vector<ii> chlt; //anotar mudancas no lt pra desfazer
mark.resize(vec.size()+3,0);
nx.resize(vec.size()+3,0);
for(ii i = 1; i <= vec.size(); i++) {
ii x = vec[i-1];
// cout << x << " ";
if(lt[x] != 0) {
nx[lt[x]] = i;
vlr.pb(mp(lt[x],i-1));
lt[x] = 0;
}
else {
lt[x] = i;
chlt.pb(x);
}
}
for(auto X : vlr) {
ii l = X.fr;
ii r = X.sc;
// cout << l << " - " << r << endl;
vector<pair<ii,ii>> ans;
bool ok = true;
for(ii i = l; i <= r; i++) {
if(nx[i] == 0) {
ans.pb(mp(vec[i-1],i));
}
else {
if(nx[i] <= r) i = nx[i]-1;
else if(!mark[i]) ans.pb(mp(vec[i-1],i));
else ok = false;
}
}
if(!ok) continue;
// cout << ans.size() << " " << l << " " << r << endl;
for(auto x : ans) {
cout << x.fr << " ";
mark[x.sc] = 1;
}
cout << endl;
}
for(auto x : chlt) {
lt[x] = 0;
}
}
}
int main() {
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.in", "r", stdin);
//freopen("out.out", "w", stdout);
ii tt = 1;
// cin >> tt;
while(tt--) solve();
}
