TLE

#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 reseta(A) memset(A, 0, sizeof(A))

const int mod = 1e9 + 7;

using namespace std;

int v[1005][1005];
int n, m;
bool check[1005];

void reset()
{
    for(int i = 0; i <= n; i++)
        check[i] = true;
}

void dfs(int u)
{
    check[u] = false;
//  cout << u << " ";
    for(int i = 1; i <= n; i++)
    {
        if(v[u][i] && check[i])
        {
            dfs(i);
        }
    }
}

bool kt(int i, int j)
{
    reset();
    dfs(1);
    for(int k = 1; k <= n; k++)
    {
        if(check[k])
            return false;
    }
    return true;
}

void solve()
{
    cin >> n >> m;
    int x, y;
    for(int i = 0; i < m; i++)
    {
        cin >> x >> y;
        v[x][y] = v[y][x] = 1;
    }
    for(int i = 1; i < n; i++)
    {
        for(int j = i + 1; j <= n; j++)
        {
            if(v[i][j])
            {
                v[i][j] = v[j][i] = 0;
                if(!kt(i, j))
                    cout << i << " " << j << " ";
                v[i][j] = v[j][i] = 1;
            }
        }
    }
    cout << el;
}

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