#include <iostream>
#include <vector>
#include <set>
#include <array>
#include <algorithm>

using namespace std;

static int n;
static vector<set<int> > binds;
static array<int, 5> complex;
static vector<array<int, 5> > results;

void load()
{
    cin >> n;
    for(int i = 0; i < n; i++)
    {
        binds.push_back(set<int>());
    }

    int m, a, b;
    cin >> m;
    for(int i = 0; i < m; i++)
    {
        cin >> a >> b;
        binds[a].insert(b);
        binds[b].insert(a);
    }
}

void search(int phase, int node, int increments)
{
    for(int i : binds[node])
    {
        if(i < complex[0]) continue;

        int connections = 0;
        bool close = false;
        for(auto bind : binds[i])
        {
            for(int j = 0; j < phase; j++)
            {
                if(bind == complex[j]) connections++;
            }
            if(bind == complex[0]) close = true;
        }

        if((phase < 4 && connections != 1) || (phase == 4 && (connections != 2 || !close))) continue;

        if(increments < 2 || i < node)
        {
            complex[phase] = i;
            if(phase == 4)
            {
                results.push_back(complex);
                sort(results.back().begin(), results.back().end());
                continue;
            }

            search(phase + 1, i, (i < node) ? increments : increments + 1);
        }
    }
}
int main()
{
    ios::sync_with_stdio(false);
    load();

    for(int i = 0; i < n; i++)
    {
        for(auto k : binds[i])
        {
            if(k < i) continue;

            complex[0] = i;
            complex[1] = k;
            search(2, k, 1);

            sort(results.begin(), results.end());
            for(auto res : results)
            {
                for(int j = 0; j < 5; j++)
                {
                    cout << res[j] << " ";
                }
                cout << endl;
            }
            results.clear();
        }
    }

    return 0;
}