#include <bits/stdc++.h>

#define ll long long
#define el endl
#define umi unordered_map<int, int>
#define umll unordered_map<ll, ll>
#define all(vect) vect.begin(), vect.end()
#define reset(A) memset(A, 0, sizeof(A))

const int mod = 1e9 + 7;

using namespace std;

int v[1005][1005];
int a[1005][2];
int n, m;
vector<pair<int, int>> res;
int check[1005];
void dfs(int u)
{
    check[u] = 1;
//  cout << u << " ";
    for(int i = 1; i <= n; i++)
    {
        if(v[u][i] && check[i] == 0)
        {
            dfs(i);
        }
    }
}

void solve()
{
    cin >> n >> m;
    res.clear();
    reset(v);
    int x, y;
    for(int i = 0; i < m; i++)
    {
        cin >> x >> y;
        a[i][0] = x;
        a[i][1] = y;
        v[x][y] = 1;
        v[y][x] = 1;
    }
    for(int i = 0; i < m; i++)
    {
        reset(check);
        v[a[i][0]][a[i][1]] = 0;
        v[a[i][1]][a[i][0]] = 0;
//      cout << el << el;
        dfs(1);
//      cout << el << el;
        bool ok = true;
        for(int j = 1; j <= n; j++)
        {
            if(check[j] == 0)
            {
                ok = false;
                break;
            }

        }
        if(!ok)
        {
            cout << a[i][0] << " " << a[i][1] << " ";
        }
        v[a[i][0]][a[i][1]] = 1;
        v[a[i][1]][a[i][0]] = 1;
    }
//  for(int i = 0; i < res.size(); i++)
//  {
//      cout << res[i].first << " " << res[i].second << " ";
//  }
    cout << el;
}

int main()
{
    int t = 1;
    cin >> t;
//  cin.ignore();
    while(t--)
    {
        solve();
    }
    return 0;
}