#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include <unistd.h>
#include <algorithm>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#include <string>

#define pb push_back
#define mp make_pair
#define ll long long
#define FOR(i, A, N) for(int (i) = (A); (i) < (N); (i)++)
#define REP(i, N) for(int (i) = 0; (i) < (N); (i)++)

using namespace std;

vector<int> nxt[111111];
int curr[6];
vector< vector<int> > res;

void find(int u, int num) {
    int x = 0;
    bool connects = false;
    REP(j, nxt[u].size()) {
        REP(k, num) if(curr[k] == nxt[u][j]) x++;
        if(nxt[u][j] == curr[0]) connects = true;
    }
    if((num < 5 && (x != 1)) || (num==5 && x != 2))
        return;
    if(num == 5 && connects == false)
        return;
    if(num == 5) {
        vector<int> cres;
        REP(k, 5) cres.pb(curr[k]);
        sort(cres.begin(), cres.end());
        res.pb(cres);
        return;
    }
    REP(j, nxt[u].size()) {
        int v = nxt[u][j];
        if(v > curr[0] && (num < 4 || v > curr[1])) {
            curr[num] = v;
            find(v, num+1);
        }
    }
}

int main() {
    int n,m;
    scanf("%d%d", &n, &m);
    REP(i, m) {
        int u,v;
        scanf("%d%d", &u, &v);
        nxt[u].pb(v);
        nxt[v].pb(u);
    }
    REP(i, n) REP(j, nxt[i].size()) {
        int v = nxt[i][j];
        if(v > i) {
            curr[0] = i; curr[1] = v;
            find(v, 2);
        }
    }
    sort(res.begin(), res.end());
    REP(i, res.size()) {
        REP(j, res[i].size()) {
            printf("%d", res[i][j]);
            if(j != res[i].size()-1) printf(" ");
        }
        printf("\n");
    }
    return 0;
}